Morbilidad de las fracturas vertebrales osteoporóticas durante el aislamiento social en la pandemia COVID-19 / Osteoporotic vertebral fractures morbidity during social isolation on COVID-19 pandemic

Introducción: la pandemia por COVID-19 afectó negativamente los sistemas de salud. Las fracturas vertebrales osteoporóticas y el aislamiento social se relacionan con mayor morbimortalidad. Objetivos: caracterizar la morbilidad de las fracturas vertebrales osteoporóticas y evaluar una posible relación entre morbilidad y nivel de aislamiento social se-cundario al estado de pandemia. Material y métodos: estudio observacional, analítico y transversal. Resultados: se incluyeron en el estudio 45 adultos. La fractura fue mayorita-riamente lumbar con una evolución superior de 3 meses. El 35% presentaba seguimiento, el 48% había recibido tratamiento para osteoporosis y el 48% presentaba fracturas previas documentadas. El 46% refirió falta de accesibilidad al sistema. Se evaluó el aisla-miento social con la escala sociofamiliar de Gijón, que evidenció una situación buena en el 75% y un deterioro social intermedio/severo en el 24%. El Índice de Oswestry mostró una discapacidad mínima/moderada en el 66% y severa o mayor en el 33%. Se evaluó el dolor por la Escala análoga visual (VAS) y se obtuvo un VAS mayor de 5 en el 57%. Al comparar el grupo de situación sociofamiliar buena con el de deterioro social intermedio/severo se observó una diferencia en multipli-cidad de fracturas (p 0,030), hipovitaminosis D (p 0,045) y falta de accesibilidad (p 0,029). En discapacidad y dolor no hubo diferencias. Conclusión: el grupo con mayor aislamiento presentó una enfermedad más severa en términos de multiplicidad de fracturas e hipovitaminosis D; esto podría indicar una asociación entre aislamiento social secundario al estado de pandemia y morbilidad por las fracturas vertebrales. (AU)

Introduction: the COVID-19 pandemic had a negative impact on healthcare systems. Osteoporotic vertebral fractures and social isolation have a significant morbidity in our setting. Objectives: to characterize the morbidity of osteoporotic vertebral fractures and evaluate a potential relationship between morbidity and the level of social isolation secondary to the pandemic. Material and methods: observational, analytical and cross-sectional study. Results: forty-five adults were included. Fractures were mostly lumbar with a history of over 3 months. Thirty-five percent (35%) had been followed-up, 48% had been treated for osteoporosis and 48% had previous documented fractures. Forty-six percent (46%) reported lack of accessibility to healthcare. Social isolation was measured using Gijón ́s social-familial evaluation scale, which showed a good situation in 75% of cases and an intermediate/severe social deterioration in 24%. According to the Oswestry index, disability was minimal/moderate in 66% of cases and severe or worse in 33%. Pain was assessed using the Visual Analogue Scale (VAS), with a score greater than 5 recorded in 57% of patients. When comparing the group with a good social-familial situation vs. the group with intermediate/severe social deterioration, differences were found in multiplicity of fractures (p 0.030), hypovitaminosis D (p 0.045) and lack of accessibility (p 0.029). No differences were found in disability and pain. Conclusion: the group with higher levels of isolation exhibited more severe disease in terms of multiplicity of fractures and hypovitaminosis D, which might suggest an association between social isolation secondary to the pandemic and morbidity due to vertebral fractures. (AU)

Vitamina D y embarazo: una experiencia piloto / Vitamin D and pregnancy: a pilot experience

La insuficiencia de vitamina D (VD) en el embarazo se relaciona con una mayor incidencia de cesáreas, preeclampsia y partos prematuros. Objetivo: evaluar si el grado de insuficiencia de VD se asocia a mayor número de cesáreas y evaluar la correlación entre la 25 hidroxivitamina D (25OHD) materna y en sangre del cordón del recién nacido. Las mujeres (n=127) se dividieron según sus niveles de 25OHD (ng/mL):G1:<20 (deficiencia), G2:20-30 (insuficiencia), G3:>30 (suficiencia). Se registraron edad; edad gestacional (EG); índice de masa corporal (IMC); tensión arterial sistólica y diastólica; tipo de parto y la estación del año en que se tomó la muestra. Se determinaron calcemia (ng/mL); 25OHD; parathormona intacta (pg/mL); fosfatasa alcalina ósea (UI/L) y crosslaps (pg/mL). La edad media fue de 26±6 años y la EG de 35,8±2,7 semanas, sin diferencias entre grupos. El porcentaje de cesáreas fue mayor en G1 que en G2 y G3 (31,3%, 21,4% y 25%, respectivamente; p<0,05). El mayor porcentaje de muestras se tomó en primavera (p<0,05). No se observaron diferencias en las demás variables maternas estudiadas. La 25OHD materna correlacionó positivamente con los valores de la sangre de cordón de sus respectivos recién nacidos (r= 0,67; p<0,0001). Independientemente de la época del año y del IMC, se observó que un porcentaje significativo de las mujeres embarazadas estudiadas tenía niveles de 25OHD inferiores a 30 ng/mL. Conclusión: evidenciamos que la deficiencia de VD materna se asoció al número de cesáreas. Asimismo, los niveles séricos de 25OHD en sangre de cordón umbilical correlacionaron significativamente con los maternos. (AU)

Vitamin D (VD) insufficiency in pregnancy is associated with a higher incidence of cesarean section, preeclampsia, and preterm delivery. Objective: to evaluate if the degree of VD insufficiency is associated with the incidence of cesarean section and to determine the correlation between maternal and newborn cord blood 25-hydroxy VS (25OHD). Women (n=127) were divided according to their 25OHD levels (ng/mL): G1:<20 (deficiency), G2:20-30 (insufficiency), G3:>30 (sufficiency). Age; gestational age (GA); body mass index (BMI); systolic and diastolic blood pressure (mmHg); type of delivery and the season of the year in which the sample was taken were recorded. Calcemia (ng/mL); 25OHD; intact parathormone (pg/mL); bone alkaline phosphatase (IU/L) and Crosslaps (pg/mL) levels were determined. Mean age was 26±6 years and GA was 35.8±2.7 weeks with no differences among groups. The % of cesarean sections was higher in G1 than in G2 and G3 (31.3%, 21.4% and 25%; p<0.05). The highest % of samples were taken in spring (p<0.05). No differences were observed in the other maternal variables studied. Maternal serum 25OHD levels correlated positively with those of cord blood from their respective newborns (r=0.67; p<0.0001). Regardless the season of the year and BMI, a high % of the studied pregnant women presented 25OHD levels lower than 30 ng/ml. Conclusion: we found that maternal VD deficiency is associated with the number of cesarean sections. In addition, 25OHD levels in the newborn significantly correlate with maternal serum levels. (AU)

Asociación entre bajos niveles de vitamina D y deterioro cognitivo en personas mayores chilenas: Resultados de la Encuesta Nacional de Salud 2016-2017 / Association between low vitamin D levels and cognitive impairment in Chilean older adults: findings of the National Health Survey 2016-2017

INTRODUCTION: Recent studies have shown that low vitamin D levels constitute a potential risk factor for the development of cognitive impairment. The present study aimed to investigate the association between vitamin D levels and the suspicion of cognitive impairment in Chilean older adults. MATERIAL AND METHOD: We performed a cross-sectional study, including 1,287 participants ≥ 65 years (56.8% were women, age range 65 to 97 years) from the Chilean National Health Survey. Cognitive impairment was assessed using the Mini Mental State Examination (MMSE). Participants were classified into three groups according to their vitamin D levels (> 29 ng/ml sufficient, 12-29 ng/ml deficit, and < 12 ng/ml severe deficit). The association between vitamin D levels and cognitive impairment was explored using logistic regression analysis, adjusted for confounding factors. RESULTS: The prevalence of vitamin D deficit and vitamin D severe deficit was 37.7% and 21.0%, respectively. Compared to older adults with sufficient levels of vitamin D, those with severe deficits had a 94% (OR: 1.94 [95% IC: 1.27; 1.66], p = 0.002) higher odds of cognitive impairment (unadjusted model). Adjusting according to sociodemographic factors, lifestyle, adiposity, sunlight exposure, and multimorbidity slightly attenuated the association to 61% (OR: 1.61 [95%IC: 1.03; 2.19], p = 0.046), but remain significant. CONCLUSION: A severe deficit of vitamin D was associated with higher odds of cognitive impairment in Chilean older adults independent of major confounding factors. Future studies are needed to provide causal evidence between vitamin D and the suspicion of cognitive impairment.

Vitamin D is associated with a low quality of life: a primary care study

Introduction: Some studies have described impairment in quality of life of vitamin-deficient subjects. However, little is known about this association in primary care. This study aimed to evaluate the association between vitamin D deficiency and quality of life in postmenopausal women attending primary care in the municipality of Santa Maria ­ Brazil. Methods: A cross-sectional study was carried out with postmenopausal women over 55 years of age, accompanied in primary care, from March to August 2014. These women were randomly selected among the participants of a cohort study in the municipality of Santa Maria ­ Brazil. Data were collected through a standardized questionnaire, quality of life was assessed using the Short Form-36 Health Survey (SF-36), and 25-hydroxyvitamin D were measured using the ALPCO® ELISA method. Results: Of the total of 78 studied women, 11.54% had vitamin D deficiency. Women with vitamin D deficiency had a poorer quality of life assessed by SF-36. In the regression analysis, both vitamin D deficiency and falls were independently associated with a lower physical component of the SF-36. Conclusion: Vitamin D deficiency is associated with poorer quality of life in the studied postmenopausal women.

Functionality and 25-hydroxyvitamin D levels in institutionalized older adults / Funcionalidade e níveis de 25-hidroxivitamina D em idosos institucionalizados

OBJECTIVES: To evaluate the frequency of hypovitaminosis D among older adults and its association with the level of functionality. METHODS: This cross-sectional observational study of older adults residing in a non-profit long-term care facility assessed functionality with the Katz Index of Independence in Activities of Daily Living. Vitamin D levels were classified as: deficient (< 20 ng/mL), insufficient (21-29 ng/mL), or normal (≥ 30 ng/mL). We used the chi-square test and Student's t-test to compare dichotomous and continuous variables, respectively. Analysis of variance with Tukey's post hoc test was used to assess differences between groups. RESULTS: The sample consisted of 63 individuals whose mean age was 81 (61-113) years: 36 (55.4%) women and 27 (44.6%) men. The mean vitamin D level was 18.6 ng/mL, being < 30 ng/mL in 84.1%. The level was normal in 10 (15.9%), insufficient in 17 (27%), and deficient in 36 (57.1%). Vitamin D deficiency was present in 76.5% of those with total functional dependence (Katz = 5-6). CONCLUSIONS: We observed a high frequency of hypovitaminosis D, especially vitamin D deficiency, which was very common among those with significant functional dependence.

OBJETIVOS: Avaliar a frequência de hipovitaminose D em idosos de uma instituição filantrópica de longa permanência e sua associação com grau de funcionalidade. METODOLOGIA: Estudo transversal, observacional e analítico de idosos de uma instituição filantrópica de longa permanência. A funcionalidade foi avaliada pela Escala de Katz. Os níveis de vitamina D foram classificados em: deficiência (valores menores que 20 ng/mL); insuficiência (valores entre 21 - 29 ng/mL) e normais (valores igual ou superior a 30 ng/mL). Empregamos teste qui-quadrado e t de student, para compararmos variáveis dicotômicas e contínuas, respectivamente; e análise de variância (ANOVA) com teste post hoc de Tukey, para avaliarmos as diferenças entre os grupos. RESULTADOS: Sessenta e três indivíduos foram analisados com média de idade de 81 anos (61 - 113), sendo 36 (55,4%) mulheres e 27 (44,6%) homens. A média de vitamina D foi 18,6 ng/mL, 84,1% com níveis menores que 30 ng/mL; dez apresentaram níveis normais (15,9%), 17 com insuficiência (27%) e 36 com deficiência (57,1%); ainda, 76,5% dos portadores de dependência funcional total (Katz = 5 - 6) apresentam deficiência de vitamina D. CONCLUSÕES: Observamos uma alta frequência de hipovitaminose D, especialmente deficiência, muito frequentes naqueles com dependência funcional importante

The importance of optimal 25-hydroxyvitamin D levels in the glycemic control of older adults with type 2 Diabetes Mellitus: Data from the study on aging and longevity EELO

INTRODUCTION: Optimal serum levels of vitamin D are of great importance, especially in populations with comorbidities such as Diabetes Mellitus (DM). OBJECTIVE: The study evaluated the relationship between hypovitaminosis D and glycemic control in older adults with type 2 DM. METHODS: Cross-sectional and prospective study, part of the EELO project (Study on Aging and Longevity), conducted in Southern Brazil. Glycated hemoglobin (diabetes ≥6.5%) and serum levels of vitamin D (25(OH)D) were evaluated. Hypovitaminosis D was determined using cutoff points <20 and <30 ng/mL). Multivariate logistic regression was used to assess the risk of having uncontrolled DM. RESULTS: Of the 120 older adults included in the study, aged between 60 and 87 years, 74.2% were women, 66.7% used hypoglycemic medications and 75.8% exhibited uncontrolled diabetes. An inverse correlation was observed between the levels of 25(OH) D and glycated hemoglobin (rS=-0.19, p=0.037), suggesting that low levels of vitamin D are associated with poor glycemic control in diabetic individuals. The prevalence of hypovitaminosis D when using the cutoff points of <20 and <30 ng/mL were 34.2% and 75.0%, respectively. The odds ratio (OR) analysis showed that individuals with 25(OH)D<20ng/mL have almost 4 times more risk of having uncontrolled DM (OR:3.94; CI95%:1.25-12.46, p=0.02) when compared to the older adults with sufficient levels of vitamin D. CONCLUSION: The results indicate that the optimal serum levels currently recommended for 25(OH)D should preferably be 30 ng/mL or higher to contribute to better glycemic control in older adults with type 2 DM.

INTRODUÇÃO: Os níveis séricos ideais de vitamina D são de grande importância, especialmente na população com comorbidades como o Diabetes Mellitus (DM). OBJETIVO: O estudo avaliou a relação entre hipovitaminose D e controle glicêmico em idosos com DM tipo 2. MÉTODOS: Estudo transversal e prospectivo, parte do projeto EELO (Estudo sobre Envelhecimento e Longevidade), no Sul do Brasil. A hemoglobina glicada (diabetes ≥6,5%) e os níveis séricos de vitamina D (25(OH)D) foram avaliados. Hipovitaminose D foi determinada usando ponto de corte <20 e <30 ng/mL. Regressão logística multivariada foi utilizada para avaliar o risco de ter DM descompensado. RESULTADOS: Dos 120 idosos incluídos no estudo, idade entre 60 a 87 anos, 74,2% eram mulheres, 66,7% faziam uso de medicamentos hipoglicemiantes e 75,8% apresentavam diabetes descompensada. Uma correlação inversa foi observada entre os níveis de 25(OH)D e hemoglobina glicada (rS=-0,19; p=0.037), sugerindo que baixos níveis de vitamina D está associado a um pior controle glicêmico em diabéticos. A prevalência de hipovitaminose D quando se utiliza ponto de corte <20 e <30 ng/mL foi de 34,2% e 75,0%, respectivamente. A análise Odds ratio (OR) mostrou que indivíduos com 25(OH)D<20 ng/mL tem quase 4 vezes mais risco de ter DM descompensado (OR:3,94; IC95%:1,25­12,46; p=0,02) quando comparado aos idosos com níveis suficientes de vitamina D. CONCLUSÃO: Os resultados indicam que os níveis sérios ideais atualmente recomendados para 25(OH)D maior ou igual a 30 ng/ml contribuem para o melhor controle glicêmico na população idosa com DM tipo 2.

Low serum levels of vitamin D significantly increase the risk of death in older adults with hip fractures: a prospective cohort / Baixos níveis séricos de vitamina D aumentam significativamente o risco de morte em idosos com fraturas de quadril: coorte prospectiva

ABSTRACT Objective: to evaluate the relationship between 25(OH)D3 levels and fatal outcome in patients over 60 years of age undergoing surgical repair of hip fractures. Methods: prospective cohort of patients undergoing surgical repair of hip fractures. At admission, 25(OH)D3 levels were measured, among other parameters. Patients were followed for at least 1 year, and incident mortality was recorded. Results: 209 patients were included in the study, with a mean age of 79.5 ± 7.6 years among survivors and 80.7 ± 8.2 years among those who died in the first postoperative year (p=0.346). The 25(OH)D3 levels of survivors were significantly higher than those of patients who died (p=0.003). After adjusting for confounding variables, 25(OH)D3 levels below 12.5ng/mL were significant risk factors regardless of mortality (adjusted OR: 7.6; 95% CI: 2.35 to 24.56). Conclusions: our data show that serum 25(OH)D3 levels below 12.5ng/mL significantly and independently increased the risk of mortality in the first year after surgical repair of low-energy hip fracture in patients over 60 years of age in the geographic region where this study was conducted. Low albumin also showed a significant association with mortality in these patients. All other factors had no significant associations.

RESUMO Objetivo: avaliar a relação entre os níveis de 25(OH)D3 e o desfecho fatal em pacientes acima de 60 anos submetidos a correção cirúrgica de fratura de quadril. Métodos: coorte prospectiva de pacientes submetidos a correção cirúrgica de fraturas de quadril. À admissão, foram medidos os níveis de 25(OH)D3, entre outros parâmetros. Os pacientes foram acompanhados por, pelo menos, um ano e a mortalidade foi registrada. Resultados: foram incluídos 209 pacientes no estudo, com média de idade de 79,5 ± 7,6 anos entre os sobreviventes e 80,7 ± 8,2 anos entre os que morreram no primeiro ano de pós-operatório (p=0,346). Os níveis de 25(OH)D3 dos sobreviventes foram significativamente maiores do que os dos pacientes que morreram (p=0,003). Após o ajuste para variáveis de confusão, níveis de 25(OH)D3 abaixo de 12,5ng/mL foram fator de risco significativo, independentemente da mortalidade (OR ajustado 7,6; IC 95% 2,35 24,56). Conclusões: níveis séricos de 25(OH)D3 abaixo de 12,5ng/mL aumentaram significativa e independentemente o risco de morte no primeiro ano após o reparo cirúrgico de fratura de quadril de baixa energia em pacientes com mais de 60 anos de idade na região geográfica onde este estudo foi realizado. A albumina baixa também teve associação significativa com a mortalidade nesses pacientes. Todos os outros fatores não tiveram associações significativas.

Insuficiência de vitamina D e fatores associados: um estudo com idosos assistidos por serviços de atenção básica à saúde / Vitamin D insufficiency and factors associated: a study with older adults people from primary health care network

Resumo O objetivo deste artigo é analisar a insuficiência de vitamina D e fatores associados em idosos assistidos na atenção primária à saúde. Trata-se de um estudo transversal que avaliou 533 idosos (≥ 60 anos) em três cidades do estado de São Paulo, Brasil. Foi avaliada a 25-hidroxivitamina D (25 OH D) sérica por quimioluminescência. Os fatores avaliados foram condições sociodemográficas (sexo, faixa etária, etnia, escolaridade, renda, estado civil), de saúde (doenças referidas), composição corporal (IMC, circunferência da cintura), estilo de vida (atividade física e tabagismo) e exposição solar (finalidade, duração, frequência e horário de exposição, partes expostas, uso de protetor solar, tipo de pele). A prevalência de insuficiência foi de 64,5%, com associação para sexo feminino, etnia não brancos/não declarados, baixo peso, circunferência da cintura elevada (risco para DCV) e inatividade física. Houve associação negativa para exposição solar habitual de mãos, braços e pernas, durante atividade de lazer, deslocamentos diários e atividade física e entre as 9h e 15h. Os achados mostram a relevância de fatores como sexo, etnia, composição corporal, atividade física e hábitos de exposição solar na alta prevalência de níveis inadequados de vitamina D em idosos.

Abstract This article aims to analyze vitamin D insufficiency and factors associated among older adults using primary health care services. This is a cross-sectional study that evaluated 533 older adults individuals (≥ 60 years old) in three cities in the state of São Paulo, Brazil. Serum level of 25-hydroxyvitamin D (25-OHD) was evaluated by chemiluminescence. The factors evaluated were sociodemographic information (sex, age group, ethnicity, education, income, marital status), health conditions (reported diseases), body composition (BMI, waist circumference), lifestyle (physical activity and smoking), and sun exposure (purpose, duration, frequency, time of exposure, exposed body parts, use of sunscreen, skin type). The prevalence of vitamin D insufficiency was 64.5%, presenting association with female participants, non-white/unreported ethnicity, low weight, high waist circumference (risk for CVD - cardiovascular disease), and physical inactivity. Negative association was observed with habitual sun exposure of hands, arms and legs, during leisure activities, daily commuting and physical activity, and between 9 am and 3 pm. The findings show the relevance of factors such as sex, ethnicity, body composition, physical activity, and sun exposure habits in the high prevalence of inadequate levels of vitamin D among older adults.

Vitamin D and bone health in adults: a systematic review and meta-analysis / Vitamina D e saúde óssea em adultos: uma revisão sistemática e metanálise

Abstract Low bone health is associated with vitamin D deficiency in older individuals; however, this association is not well established in adults. The aim of the study was to analyze the association between serum concentrations of 25-hydroxyvitamin D and bone health in adults by systematic review and meta-analysis. The search was carried out in the LILACS, PubMed, Scopus, Web of Science, ScienceDirect databases from March 2017 to October 2018 with adult individuals (20-59 years). Bone health was evaluation performed through dual X-ray absorptiometry and serum concentrations of 25(OH)D. The random effect model was used to analyze data from bone mineral content and bone mineral. Random effects models were used and the sources of heterogeneity were explored by means of meta-regression. Thirty-five articles were selected. There was positive correlation between vitamin D and bone health in most of the evaluated sites. Correlation was observed in the analysis of subgroups for lumbar spine among men. When stratified, the studies presented high heterogeneity, which was explained by the sample size, mean serum vitamin D levels and risk of bias. Vitamin D is positively correlated to bone health in adult individuals.

Resumo A baixa saúde óssea está associada à deficiência de vitamina D em indivíduos mais velhos; no entanto, isso não está bem estabelecido em adultos. O estudo objetivou-se analisar a associação entre concentrações séricas de 25-hidroxivitamina D e baixa saúde óssea em adultos por revisão sistemática e metanálise. A pesquisa foi realizada nas bases LILACS, PubMed, Scopus, Web of Science, ScienceDirect de março de 2017 a outubro de 2018 com indivíduos adultos (20-59 anos). A avaliação da saúde óssea foi realizada através da absorciometria dupla de raios X e concentrações séricas de 25(OH)D. O modelo de efeito aleatório foi utilizado para analisar dados do conteúdo mineral ósseo e densidade mineral óssea. Modelos de efeitos aleatórios foram utilizados e a heterogeneidade foi explorada por meio de meta-regressão. Trinta e cinco artigos foram selecionados. Houve correlação positiva entre a vitamina D e a saúde óssea na maioria dos locais avaliados. Observou-se correlação na análise de subgrupos da coluna lombar entre homens. Quando estratificados, os estudos apresentaram alta heterogeneidade, explicada pelo tamanho da amostra, pelos níveis séricos médios da vitamina e pelo risco de viés. A vitamina D está positivamente correlacionada com a saúde óssea em indivíduos adultos.

Racial differences in the relationship between high-normal 25-hydroxy vitamin d and parathyroid hormone levels in early stage chronic kidney disease / Diferenças raciais na relação entre níveis normais-elevados de 25-hidroxivitamina d e hormônio da paratireóide na doença renal crônica em estágio inicial

ABSTRACT Aim: Current guidelines do not address between-person variability in markers of bone and mineral metabolism across subgroups of patients, nor delineate treatment strategies based upon such factors. Methods: A cross sectional study was carried out to analyze data from 20,494 United States Veterans and verify the variability of Vitamin D (25(OH)D) and parathyroid hormone (PTH) levels across race and stage of chronic kidney disease. Results: PTH levels were higher in Black Americans (BA) than White Americans (WA) at all levels of 25(OH)D and across eGFR strata. There was a progressive decline in PTH levels from the lowest (25(OH)D < 20) to highest quartile (25(OH)D >=40) in both BA (134.4 v 90 pg/mL, respectively) and WA (112.5 v 71.62 pg/mL) (p<0.001 for all comparisons). Conclusion: In this analysis, higher than normal 25(OH)D levels were well tolerated and associated with lower parathyroid hormone values in both blacks and whites. Black Americans had higher PTH values at every level of eGFR and 25(OH)D levels suggesting a single PTH target is not appropriate.

RESUMO Objetivo: as diretrizes atuais não abordam a variabilidade entre as pessoas nos marcadores do metabolismo ósseo e mineral em subgrupos de pacientes, nem traçam estratégias de tratamento com base em tais fatores. Métodos: realizamos um estudo transversal para analisar dados de 20.494 veteranos de guerra dos Estados Unidos e verificar a variabilidade nos níveis de vitamina D (25 (OH) D) e hormônio da paratireóide (PTH) entre a raça e o estágio da doença renal crônica. Resultados: os níveis de PTH foram maiores em americanos negros (AN) do que em americanos brancos (AB) em todos os níveis de 25 (OH) D e em todos os estratos de TFGe. Houve um declínio progressivo nos níveis de PTH do quartil mais baixo (25 (OH) D <20) para o quartil mais alto (25 (OH) D> = 40) em AN (134,4 v 90 pg/mL, respectivamente) e AB (112,5 v 71,62 pg/mL) (p <0,001 para todas as comparações). Conclusão: Nesta análise, níveis de 25 (OH) D acima do normal foram bem tolerados e associados a valores mais baixos do hormônio da paratireóide em negros e brancos. Os americanos negros tinham valores de PTH mais altos em todos os níveis de TFGe e 25 (OH) D, sugerindo que uma única meta de PTH não é apropriado.

Deficiência de vitamina d e mortalidade cardiovascular na doença renal crônica: revisão integrativa / Deficiencia de vitamina d y mortalidad cardiovascular en la enfermedad renal crónica: revisión integradora / Vitamin d deficiency and cardiovascular mortality in chronic kidney disease: integrative review

RESUMO Objetivo: analisar os estudos científicos desenvolvidos sobre a deficiência de vitamina D e a mortalidade por causa cardiovascular nas pessoas com doença renal crônica. Método: Trata-se de uma revisão integrativa da literatura a partir das bases de dados LILACS, Pub Med, Medline e na biblioteca eletrônica SciELO, utilizando os descritores deficiência de vitamina D, mortalidade cardiovascular e doença renal crônica, sendo selecionados 14 artigos para análise. Resultados: A partir da análise dos artigos selecionados, foi possível identificar que a deficiência de vitamina D e a mortalidade cardiovascular são condições muito frequentes em renais crônicos e, por isso, discutem-se hipóteses de que a correção desta deficiência pode exercer efeitos benéficos sobre a doença e mortalidade cardiovascular nessa população. Conclusão: Há uma intrínseca relação entre a carência de vitamina D e a mortalidade cardiovascular. Entretanto, ainda é discutível se a suplementação de vitamina D reduz a mortalidade cardiovascular nos doentes renais crônicos. Tal hipótese precisa ser testada em ensaios clínicos, ensejando a necessidade de se desenvolver mais pesquisas sobre o tema.

RESUMEN Objetivo: analizar los estudios científicos desarrollados sobre la deficiencia de vitamina D y la mortalidad por causa cardiovascular en las personas con enfermedad renal crónica. Método: se trata de una revisión integradora de la literatura a partir de las bases de datos LILACS, PubMed, Medline yen la biblioteca electrónica SciELO, utilizando los descriptores deficiencia de vitamina D; mortalidad cardiovascular y enfermedad renal crónica, siendo seleccionados 14 artículos para el análisis. Resultados: a partir del análisis de los artículos seleccionados, fue posible identificar que la deficiencia de vitamina D y la mortalidad cardiovascular son condiciones muy frecuentes en enfermos renales crónicos y, por ello, se discuten hipótesis de que la corrección de esta deficiencia puede ejercer efectos benéficos sobre la enfermedad y mortalidad cardiovascular en esta población. Conclusión: hay una intrínseca relación entre la carencia de vitamina D y la mortalidad cardiovascular. Sin embargo, aúnes discutible si la suplementación de vitamina D reduce la mortalidad cardiovascular en los enfermos renales crónicos. Tal hipótesis necesita ser probada en ensayos clínicos, fomentando la necesidad de desarrollarse más investigaciones sobre el tema.

ABSTRACT Objective: To analyze scientific studies that have addressed vitamin D deficiency and cardiovascular mortality in people with chronic kidney disease. Method: This is an integrative literature review conducted through the LILACS, PubMed and Medline databases, and through the SciELO electronic library, using the 'vitamin D deficiency', 'cardiovascular mortality' and 'chronic kidney disease' descriptors, with 14 articles being selected for analysis. Results: By analyzing the selected articles, it was possible to identify that vitamin D deficiency and cardiovascular mortality are very common conditions in chronic renal patients and, for this reason, there are hypotheses that correcting this deficiency may have beneficial effects on the disease and cardiovascular mortality in this population. Conclusion: There is an intrinsic relationship between vitamin D deficiency and cardiovascular mortality. However, it is still debatable whether vitamin D supplementation reduces cardiovascular mortality in chronic renal patients. Such hypothesis needs to be tested in clinical trials, which gives cause for the need to develop further research on the theme.

El rol de la suplementación con vitamina D en la infección por COVID-19 / The role of vitamin D supplementation on COVID-19 infection

La Vitamina D es un micronutriente esencial que obtenemos a partir de la síntesis dérmica tras la radiación solar ultravioleta. Diferentes estudios han evidenciado que la vitamina D tiene diversos efectos a nivel del sistema inmune, y cumple un rol esencial en la respuesta ante infecciones virales respiratorias. A partir de un caso clínico real, en contexto de la actual pandemia de COVID-19, revisamos la evidencia disponible y encontramos que no existen pruebas que respaldan la suplementación con vitamina D para prevenir la infección o los desenlaces adversos de esta enfermedad. (AU)

Vitamin D is an essential micronutrient that we obtain from dermal synthesis following solar ultraviolet radiation. Different studies have shown that vitamin D has various effects on the immune system and plays an essential role in the response to respiratory viral infections. Based on a real clinical case, in the context of the current COVID-19 pandemic, we reviewed the available evidence and found that there is no proof to support vitamin D supplementation to prevent the infection or the adverse outcomes of this disease. (AU)

Asociación entre los niveles séricos de vitamina D y marcadores inflamatorios en pacientes en hemodiálisis / Association between vitamin D serum levels and inflammatory markers in patients on hemodialysis

Resumen Introducción: La relación entre 25-OH-vitamina D y el sistema inmune en pacientes con enfermedad renal crónica es objeto de atención. Objetivos: Evaluar la prevalencia de la deficiencia de vitamina D en pacientes en hemodiálisis e investigar la asociación entre la vitamina D y proteína C reactiva ultrasensible (PCRus), índice neutrófilo/linfocito (INL) e índice plaqueta/linfocito (IPL). Método: Estudio transversal de 80 pacientes en hemodiálisis, divididos en dos grupos: un nivel sérico de 25-OH-vitamina D < 20 ng/mL se consideró como deficiencia de vitamina D y ≥ 20 ng/mL, como normal. Con el análisis de correlación de Spearman se definió la relación entre los parámetros. Resultados: 40 % de los pacientes presentó deficiencia de vitamina D. Hubo diferencias significativas entre los grupos en PCRus (p = 0.047), INL (p = 0.039), IPL (p = 0.042) y tratamiento con análogos de vitamina D (p = 0.022). La vitamina D tuvo una correlación negativa significativa con PCRus (p = 0.026), INL (p = 0.013) e IPL (p = 0.022). Conclusiones: La deficiencia de vitamina D fue de 40 %. Los niveles de PCRus, INL e IPL fueron significativamente más altos ante deficiencia de vitamina D. Se encontró correlación inversa significativa entre vitamina D y PCRus, INL e IPL.

Abstract Introduction: The relationship between 25-OH-vitamin D and the immune system in patients with chronic kidney disease is a subject of attention. Objectives: To assess the prevalence of vitamin D deficiency in patients on hemodialysis and to investigate the association between vitamin D, ultra-sensitive C-reactive protein (US-CRP), neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR). Method: Cross-sectional study of 80 patients on hemodialysis, divided into two groups: a serum 25-OH-vitamin D level < 20 ng/mL was considered to be vitamin D deficiency and a serum level ≥ 20 ng/mL was regarded as normal. The relationship between the parameters was defined with Spearman's correlation analysis. Results: 40 % of the patients had vitamin D deficiency. There were significant differences between groups in US-CRP (p = 0.047), NLR (p = 0.039), PLR (p = 0.042) and treatment with vitamin D analogues (p = 0.022). Vitamin D had a significant negative correlation with US-CRP (p = 0.026), NLR (p = 0.013) and PLR (p = 0.022). Conclusions: The prevalence of vitamin D deficiency was 40 %. The values of US-CRP, NLR and PLR were significantly higher in the presence of vitamin D deficiency. A significant inverse correlation was found between vitamin D levels and US-CRP, NLR and PLR.

Vitamin D deficiency is not associated with increased oxidative stress in chronic kidney disease pre-dialysis patients / A deficiência de vitamina D não está associada ao aumento do estresse oxidativo em pacientes renais crônicos em pré-diálise

Abstract Introduction: The progressive decline in 25-hydroxyvitamin D [25(OH)D] in chronic kidney disease (CKD) limits the kidney ability of synthesizing the vitamin. Vitamin D deficiency as defined by KDIGO (25(OH)D <20 ng/mL) is prevalent in CKD patients and associated to oxidative stress (OS). We studied a possible association between vitamin D deficiency and OS in pre-dialysis patients. Methods: A cross-sectional study with 206 CKD patients was carried out. Laboratory tests for 25(OH)D, 1,25(OH)2D, inflammatory markers, and OS were added to routine tests including creatinine, albumin, calcium, phosphorus, alkaline phosphatase, iPTH, glucose, hemoglobin, uric acid, total cholesterol, LDL, HDL, and triglycerides. Results: Vitamin D deficiency was present in 55 CKD patients and normal vitamin D levels were seen in 149 patients. There was a significant association between vitamin D and estimated glomerular filtration rate (eGRF). Homocysteine levels were best predicted by eGRF, sex, and age; high sensitivity C-reactive protein (hsCRP) by staging and BMI; nitric oxide metabolites (NOx) were increased in late disease; leptin was influenced by BMI and higher in women than man; and adiponectin levels were higher in women. Conclusions: OS biomarkers were not correlated with vitamin D deficiency but increased NOx were seen in stages 4-5 CKD patients. Even though a relatively large number of CKD patients was included and a broad number of OS and inflammatory biomarkers were used in this studied we failed to find an association between vitamin D levels and eGRF. More studies are needed to evaluate the influence of vitamin D status in OS in pre-dialysis CKD patients.

Resumo Introdução: A queda da 25-hidroxivitamina D [25 (OH) D] na doença renal crônica (DRC) limita a capacidade renal de sintetizar a vitamina. A deficiência de vitamina D, (25(OH)D<20 ng/mL), é prevalente em pacientes com DRC e associada ao estresse oxidativo (EO). Avaliamos possível associação entre a deficiência de vitamina D e EO em pacientes pré-dialíticos. Métodos: estudo transversal com 206 pacientes com DRC. Exames para 25(OH)D, 1,25(OH)2D, marcadores inflamatórios e EO foram adicionados àqueles de rotina, incluindo creatinina, albumina, cálcio, fósforo, fosfatase alcalina, iPTH, glicose, hemoglobina, ácido úrico, colesterol total , LDL, HDL e triglicerídeos. Resultados: 55 pacientes com DRC tinham deficiência de vitamina D e os 149 tinham níveis normais da vitamina. Houve uma associação significativa entre a vitamina D e a taxa estimada de filtração glomerular (TFGe). Os níveis de homocisteína foram melhor previstos pela TFGe, gênero e idade; proteína C reativa de alta sensibilidade (hsCRP) por estadiamento e IMC; os metabólitos de óxido nítrico (NOx) aumentaram na doença tardia; a leptina foi influenciada pelo IMC, e mais alta em mulheres, assim como os níveis de adiponectina. Conclusões: biomarcadores do EO não correlacionaram com a deficiência de vitamina D, mas houve aumento de NOx nos estágios 4-5 da DRC. Apesar dos grandes números de pacientes com DRC, de biomarcadores inflamatórios e EO usados neste estudo, não houve associação entre os níveis de vitamina D e a TFGe. Mais estudos são necessários para avaliar a influência do status da vitamina D no EO em pacientes com DRC em pré-diálise.

Estudo caso-controle sobre o status da vitamina D em crianças e adolescentes com esofagite eosinofílica / Case-control study on vitamin d status in children and adolescents with eosinophilic esophagitis

ABSTRACT BACKGROUND: Vitamin D is an essential fat-soluble steroid hormone and vitamin D deficiency is a global public health problem especially among children and adolescents. Factors such as the low intake of vitamin D-rich food sources, poor absorption and less exposure to the sun influence this outcome. Vitamin D has an anti-inflammatory effect in the body by promoting regulatory T cell differentiation as well as recovering T helper 17 cell response and secretion of anti-inflammatory cytokines. Eosinophilic esophagitis (EoE) is a chronic disease, histologically characterized by predominantly eosinophilic inflammation. The most common therapeutic approaches are allergen-eliminating diets, such as excluding cow's milk, egg, soy, wheat, peanuts and seafood, or more specific dietary restrictions. OBJECTIVE: To verify the serum levels of vitamin D in children and adolescents with eosinophilic esophagitis on a restricted food diet and to analyze their association with nutritional status, consumption of different food sources, exposure to the sun and skin color. METHODS: Case-control study conducted in the city of Campinas-SP, Brazil, in which included patients were aged 2 to 18 years old, and those diagnosed with eosinophilic esophagitis was referred to as the case group (n=15), meanwhile a control group (n=17) was also formed. Epidemiological data, nutritional status, data on vitamin D intake (24-hour recall - performed only by EoE patients - and self-reported intake of vitamin D food sources: milk and dairy products, canned tuna and sardines, Bull's liver, chicken eggs - applied in both groups), and daily time of sun exposure (≥30 min or ≤30 min) were recorded. The samples were collected for serum levels of 25-hydroxy-vitamin D, where sufficiency levels >30 ng/mL were considered, insufficiency 21 to 30 ng/mL, deficiency <20 ng/mL. RESULTS: There was a higher frequency of vitamin D insufficiency/ deficiency in the Eosinophilic Esophagitis group (P=0.035), even with longer sun exposure (P= 0.035). Skin color was not associated with lower levels of vitamin D in both groups studied. No difference was found in nutritional status between the groups. CONCLUSION: The present study demonstrated a higher frequency of inadequate/ deficient levels of vitamin D in children and adolescents with EoE on a restricted diet. When necessary, serum levels should be investigated and correct exposure to the sun should be encouraged, with special attention to the recommended guidelines, time spent in the sun and the appropriate clothing for correct absorption. Since exposure for more than 30 minutes in the sun does not appear to have provided a protective effect in the EoE group, even in a region with high levels of solar radiation. There was a significant difference only in the consumption of cow's milk between the case and control groups, demonstrating the low adherence to the restriction diet by the case group. No association was found between serum 25 hydroxyvitamin D levels and nutritional status. Moreover, no association regarding the adequate or inadequate status of 25 hydroxyvitamin D and the consumption vitamin D-rich foods was identified. Multicentered studies with a larger number of cases should be performed to assess serum 25 hydroxyvitamin D levels and associated factors in pediatric patients with EoE.

RESUMO CONTEXTO: A vitamina D é um hormônio esteroide solúvel em gordura essencial e sua deficiência é um problema global de saúde pública, especialmente entre crianças e adolescentes. Fatores como baixa ingestão de fontes alimentares ricas em vitamina D, baixa absorção e menor exposição ao sol influenciam esse resultado. A vitamina D tem um efeito anti-inflamatório no organismo, promovendo a diferenciação regulatória das células T e recuperando a resposta das células T auxiliares 17 e a secreção de citocinas anti-inflamatórias. A esofagite eosinofílica (EoE) é uma doença crônica, caracterizada histologicamente por inflamação predominantemente eosinofílica. As abordagens terapêuticas mais comuns são as dietas eliminadoras de alérgenos, como a exclusão de leite de vaca, ovo, soja, trigo, amendoim e frutos do mar ou restrições alimentares mais específicas. OBJETIVO: Verificar os níveis séricos de vitamina D em crianças e adolescentes com EoE em dieta restrita e, analisar sua associação com estado nutricional, consumo de fonte alimentar, exposição ao sol e cor da pele. MÉTODOS: Estudo caso-controle realizado na cidade de Campinas-SP, Brasil, no qual foram incluídos pacientes com idades entre 2 e 18 anos; aqueles com diagnóstico de EoE foram referidos como grupo de casos (n=15); um grupo controle (n=17) também foi formado. Dados epidemiológicos, estado nutricional, dados sobre a ingestão de vitamina D (recordatório de 24 horas - realizado apenas por pacientes com EoE e ingestão autorreferida de fontes alimentares de vitamina D: leite e derivados, atum e sardinha enlatada, fígado de boi, ovos de galinha - aplicados em ambos os grupos) e o tempo diário de exposição ao sol (≥30 min ou ≤30 min) foi registrado. As amostras foram coletadas para níveis séricos de 25-hidroxi-vitamina D, onde foram considerados níveis de suficiência >30 ng/mL, insuficiência 21 a 30 ng/mL, deficiência <20 ng/mL. RESULTADOS: Houve maior frequência de insuficiência / deficiência de vitamina D no grupo EoE (P=0,035), mesmo com maior exposição ao sol (P=0,035). A cor da pele não foi associada a níveis mais baixos de vitamina D nos dois grupos estudados. Não foi encontrada diferença no estado nutricional entre os grupos. CONCLUSÃO: O presente estudo demonstrou maior frequência de níveis inadequados / deficientes de vitamina D em crianças e adolescentes com EEo em dieta restrita. Quando necessário, os níveis séricos devem ser investigados e a exposição correta ao sol deve ser incentivada, com atenção especial às diretrizes recomendadas, tempo gasto ao sol e roupas adequadas para a absorção correta. Já a exposição por mais de 30 minutos ao sol não parece ter proporcionado um efeito protetor no grupo EoE, mesmo em uma região com altos níveis de radiação solar. Houve diferença significativa apenas no consumo de leite de vaca entre os grupos caso e controle, demonstrando a baixa adesão à dieta de restrição pelo grupo caso. Não foi encontrada associação entre os níveis séricos de hidroxivitamina D 25 e o estado nutricional. Além disso, não foi identificada associação quanto ao status adequado ou inadequado da 25 hidroxivitamina D e ao consumo de alimentos ricos em vitamina D. Estudos multicêntricos com número maior de casos devem ser realizados para avaliar os níveis séricos de hidroxivitamina D 25 e fatores associados em pacientes pediátricos com EEo.

Relación entre Nivel de 25 (OH) D Vitaminas y Deterioro Cognitivo en Enfermedad renal Crónica (ERC) en pacientes en diálisis y sin diálisis mediante el uso de la prueba B / Relationship between Level of 25 (OH) D Vitamins and Cognitive Impairment in Chronic Kidney Disease (CKD) in Dialysis and NonDialysis Patients Using Trial Making Test B

Deficiency in vitamin D and cognitive dysfunction commonly are associated together in patients suffering from chronic kidney disease (CKD) in both dialysis and non-dialysis patients, vitamin D develop new protective regulatory roles in the functions of CNS. Combination of low levels of vitamin D and CKD can be enrolled for devastating and lead to sever cognitive dysfunction. Patients with CKD mostly associated with Hypovitaminosisand moreover common in elderly patients and related with cognitive decline, one of the hypotheses that CKD patients commonly have a low level of vitamin D and have potential experience in accelerated cognitive decline which rarely link on this topic. Most of CKD patients particularly sensitive for developing in the deficiency of vitamin D. Reduce vitamin D intake, male absorption in compromised GIT patients, loosing of vitamin D binding protein with urine, and α-hydroxylase enzyme reduction in the kidney all are the risk factors included in the causes of 25(OH) D vitamin decrease production. Aim of study: assess cognitive function by using one validated score: trial making test B in patients with CKD in both dialysis and non-dialysis. Patients and methods: a total of 54 patients with CKD and 57 patients with ESRD on hemodialysis enrolled in this study, where CKD defined as GFR < 60 ml/min by MDRD study. Exclusion criteria include CVA, deaf and blind, and low education patients. Cognitive functions assessment done for patients who are on hemodialysis and non- dialysis by using trial B testing, this second assess spatial scanning concentration and executive function by time measuring that needed to connect the series of numbered that are sequentially and littered circles. Catastrophic shorter time completion with a maximum of 300 second indicates better performance. 25 (OH) D vitamins has assessed from each patients using direct immunoassay method, with assay at 4-110 ng/ml. Results: for patients on hemodialysis 27 (39.7%) has deficient 25(OH) D vitamin status 25 (36.7%) insufficient,20 (29.4%) had sufficient vitamin D levels, significant low level in patients on hemodialysis in comparison to those with non-hemodialysis. Trial making test B score was significantly lower in dialysis patients, significant correlation between cognitive function assessment (trial making test B) and low vitamin D level. Conclusions: the prevalence of deficiency in vitamin D in CKD especially hemodialysis patients associated with cognitive decline.

Vitamin D Toxicity / Toxicidade da Vitamina D

Abstract Fortification of food products with vitamin D was central to the eradication of rickets in the early parts of the 20th century in the United States. In the subsequent almost 100 years since, accumulating evidence has linked vitamin D deficiency to a variety of outcomes, and this has paralleled greater public interest and awareness of the health benefits of vitamin D. Supplements containing vitamin D are now widely available in both industrialized and developing countries, and many are in the form of unregulated formulations sold to the public with little guidance for safe administration. Together, this has contributed to a transition whereby a dramatic global increase in cases of vitamin D toxicity has been reported. Clinicians are now faced with the challenge of managing this condition that can present on a spectrum from asymptomatic to acute life-threatening complications. This article considers contemporary data on vitamin D toxicity, and diagnostic and management strategies relevant to clinical practice.

Resumo A suplementação de produtos alimentares com vitamina D foi fundamental para a erradicação do raquitismo no início do século XX nos Estados Unidos. Nos quase 100 anos subsequentes, o acúmulo de evidências vinculou a deficiência de vitamina D a uma variedade de desfechos, e isso tem levantado grande interesse público e conscientização dos benefícios à saúde da vitamina D. Os suplementos que contêm vitamina D estão agora amplamente disponíveis tanto nos países desenvolvidos quanto naqueles em desenvolvimento, e muitos estão na forma de formulações não regulamentadas, vendidas ao público com poucas orientações para uma administração segura. Juntos, isso contribuiu para uma transição na qual um aumento global dramático nos casos de toxicidade da vitamina D tem sido relatado. Médicos agora enfrentam o desafio de tratar essa condição que pode apresentar um espectro de complicações assintomáticas a agudas, com risco de vida. Este artigo considera dados atualizados sobre a toxicidade da vitamina D e estratégias de diagnóstico e manejo relevantes para a prática clínica.

Chronic kidney disease is a main confounding factor for 25-vitamin D measurement / A doença renal crônica é um importante fator de confusão para a dosagem de 25-hidroxivitamina D

Abstract Background: Current guidelines recommend assessment of 25-vitamin D status in patients with chronic kidney disease (CKD). Although significant differences among assays have been described, the impact of CKD on this variability has never been tested. Methods: We tested the variability between two 25-vitamin D assays in patients with CKD (eGFR < 60 mL/min/1.73m2) who had consecutive 25-vitamin D measurements in 2015 (Assay 1 - Diasorin LIASON 25 TOTAL - D assay®) and 2016 (Assay 2 - Beckman Coulter Unicel Xl 800®). The cohort consisted of 791 adult patients (122 with normal renal function and 669 with CKD - 33, 30, and 37% in stages 3, 4, and 5 on dialysis, respectively). Results: Levels of 25-vitamin D were lower and the prevalence of hypovitaminosis D using assay 1 was higher than using assay 2 in patients with CKD, regardless of similar levels of calcium, phosphate, and parathyroid hormone. As kidney function decreased, the percentage of disagreement between the assays increased. Conclusion: There is a noteworthy variability between assays in patients with CKD such that the diagnosis of hypovitaminosis D is modified. The mechanism behind this result is still unclear and might be due to a possible interference in the analytical process. However, the clinical significance is unquestionable, as the supplementation of vitamin D can be erroneously prescribed to these patients.

Resumo Antecedentes: As diretrizes atuais recomendam a avaliação do estado da 25-hidroxivitamina D em pacientes com doença renal crônica (DRC). Embora significativas diferenças entre os ensaios tenham sido descritas, o impacto da nesta variabilidade DRC nunca foi testado. Métodos: Testamos a variabilidade entre dois ensaios de 25-hidroxivitamina D em pacientes com DRC (TFGe < 60 mL/min/1,73 m2) que realizaram medidas consecutivas de 25-hidroxivitamina D em 2015 (Ensaio 1 - Diasorin LIASON 25 TOTAL - D assay® ) e 2016 (Ensaio 2 - Beckman Coulter Unicel Xl 800®). A coorte consistiu de 791 pacientes adultos (122 com função renal normal e 669 com DRC - 33, 30 e 37% nos estágios 3, 4 e 5 em diálise, respectivamente). Resultados: Os níveis de 25-hidroxivitamina D foram menores e a prevalência de hipovitaminose D foi maior utilizando o ensaio 1 do que com o ensaio 2 em pacientes com DRC, independentemente dos níveis similares de cálcio, fosfato e paratormônio. Quando a função renal diminuiu, a porcentagem de discordância entre os ensaios aumentou. Conclusão: Existe uma notável variabilidade entre os ensaios em pacientes com DRC, de modo a modificar o diagnóstico de hipovitaminose D. O mecanismo por trás desse resultado ainda não está claro e pode ser devido a uma possível interferência no processo analítico. Entretanto, o significado clínico é inquestionável, pois a suplementação de vitamina D pode ser erroneamente prescrita a esses pacientes.