Global Prevalence and Severity of Retinopathy of Prematurity over the Last Four Decades (1985-2021): A Systematic Review and Meta-Analysis.

BACKGROUND: Retinopathy of prematurity (ROP) is a vasoproliferative disease of the retina that occurs in premature infants. The prevalence of ROP reported so far is inconsistent. AIM: To conduct a systematic review to describe the trend of ROP prevalence between 1985 and 2021, and to determine the influence of countries' economic conditions on ROP prevalence. METHODS: We searched PubMed, Embase, and Google Scholar for studies published between January 1985 and December 2021 using the following MeSH terms: "retinopathy of prematurity", "ROP", "incidence", and "prevalence". Two independent reviewers examined the articles to select studies that met the selection criteria and performed data extraction and study quality assessment. For the meta-analysis, the pooled prevalence was calculated using a random-effects model and R software. RESULTS: Of 5,250 titles and abstracts, 139 original studies met the inclusion criteria; a total of 121,618 premature infants were included in these studies. The pooled prevalence of ROP was 31.9% (95% confidence interval [CI] 29.0-34.8) and that of severe ROP was 7.5% (6.5-8.7). In general, no significant differences in prevalence were found over the four decades; however, we found a higher prevalence in premature infants ≤28 weeks of gestational age. In addition, the highest ROP prevalence was found in lower-middle-income countries with high mortality rates. In contrast, the highest severe ROP prevalence was found in high-income countries. CONCLUSION: ROP remains a common cause of morbidity in premature infants worldwide. Therefore, it seems necessary to maintain early identification strategies for patients at higher risk, particularly in low- and middle-income countries.

Vitamin D levels in the pre- and post-COVID-19 pandemic periods in pediatric patients with chronic kidney disease.

Introduction: Vitamin D (VD) deficiency is common in children with chronic kidney disease (CKD) because of multiple factors. During the coronavirus disease 2019 (COVID-19) pandemic, it increased because of medicine shortage and no enough medical service for patients with non-COVID-19 diseases. Objective: To analyze the effects of the COVID-19 pandemic-related lockdown on the serum levels and status of 25-hydroxyvitamin D3 (25-[OH]D) in children with CKD. Materials and methods: This retrospective study included patients (6-18 years old) who were diagnosed with CKD stage 2-5 and routinely measured for serum VD levels between May 2019 and December 2022. Serum 25-(OH)D levels were measured before, during, and after the pandemic (2019, 2020-2021, and 2022, respectively). The daily dose of cholecalciferol supplementation and the readjustment (if required) were recorded. Results: This study included 171 patients (median age: 12 years). Before the pandemic, the median serum VD level was 25.0 ng/mL (19.3% VD deficiency). Then, VD supplementation was adjusted to 400-1,200 UI daily in 98.8% (n = 169) of patients. During the pandemic, the median VD level decreased to 22.5 ng/mL (43.3% VD deficiency). Hence, the supplementation was readjusted, and after the pandemic, the level was 28.7 ng/mL (18.7% VD deficiency), indicating a statistically significant increase in serum VD levels from the prepandemic period (p = 0.007). Conclusion: Decreased serum VD levels and increased VD deficiency frequency were observed in patients with CKD during the COVID-19 but improved after readjustment of supplementation.

[Aswer to "Comment on article "Bibliometric analysis of scientific publications on COVID-19 elaborated by staff of the Instituto Mexicano del Seguro Social""]. / Respuesta a "Comentario al artículo "Análisis bibliométrico de las publicaciones científicas sobre COVID-19 realizadas por personal IMSS"".

We thank the group headed by Jorge Valencia Alonso for taking the time to review in detail and prepare the letter about our article entitled: " Bibliometric analysis of scientific publications on COVID-19 elaborated by staff of the Instituto Mexicano del Seguro Social", which has recently been published in the Medical Journal of the Mexican Social Security Institute. Based on your observations and comments, we allow ourselves to make the following clarifications following the same sequence of your letter to the Editor.

Agradecemos al grupo encabezado por Jorge Valencia Alonso por tomarse el tiempo para revisar con detalle y elaborar la carta sobre nuestro artículo titulado: "Análisis bibliométrico de las publicaciones científicas sobre COVID-19 por personal del IMSS", que recientemente se ha publicado en la Revista Médica del Instituto Mexicano del Seguro Social. De acuerdo con sus observaciones y comentarios, nos permitimos realizar las siguientes aclaraciones siguiendo la misma secuencia de su carta al Editor.

Characteristics and outcomes of multisystem inflammatory syndrome in children: A multicenter, retrospective, observational cohort study in Mexico.

Introduction: Multisystem inflammatory syndrome in children associated with coronavirus disease 2019 (MIS-C), a novel hyperinflammatory condition secondary to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, is associated with severe outcomes such as coronary artery aneurysm and death. Methods: This multicenter, retrospective, observational cohort study including eight centers in Mexico, aimed to describe the clinical characteristics and outcomes of patients with MIS-C. Patient data were evaluated using latent class analysis (LCA) to categorize patients into three phenotypes: toxic shock syndrome-like (TSSL)-MIS-C, Kawasaki disease-like (KDL)-MIS-C, and nonspecific MIS-C (NS-MIS-C). Risk factors for adverse outcomes were estimated using multilevel mixed-effects logistic regression. Results: The study included 239 patients with MIS-C, including 61 (26%), 70 (29%), and 108 (45%) patients in the TSSL-MIS-C, KDL-MIS-C, and NS-MIS-C groups, respectively. Fifty-four percent of the patients were admitted to the intensive care unit, and 42%, 78%, and 41% received intravenous immunoglobulin, systemic glucocorticoids, and anticoagulants, respectively. Coronary artery dilatation and aneurysms were found in 5.7% and 13.2% of the patients in whom coronary artery diameter was measured, respectively. Any cause in-hospital mortality was 5.4%. Hospitalization after ten days of symptoms was associated with coronary artery abnormalities (odds ratio [OR] 1.6, 95% confidence interval [CI] 1.2-2.0). Age ≥10 years (OR: 5.6, 95% CI: 1.4-2.04), severe underlying condition (OR: 9.3, 95% CI: 2.8-31.0), platelet count <150,000 /mm3 (OR: 4.2, 95% CI: 1.2-14.7), international normalized ratio >1.2 (OR: 3.8, 95% CI: 1.05-13.9), and serum ferritin concentration >1,500 mg/dl at admission (OR: 52, 95% CI: 5.9-463) were risk factors for death. Discussion: Mortality in patients with MIS-C was higher than reported in other series, probably because of a high rate of cases with serious underlying diseases.

Correlación del ácido úrico con el grosor de la íntima media de la carótida en adolescentes con obesidad / Correlation of uric acid with carotid intima media thickness in obese adolescents

Introducción: la obesidad en la población pediátrica es un problema de salud pública. Se ha demostrado la correlación del ácido úrico y el grosor de la íntima media de la carótida en adultos. Objetivo: identificar la correlación del ácido úrico y el grosor de la íntima media de la carótida en adolescentes con obesidad. Material y métodos: se realizó un estudio observacional, transversal. Se incluyeron pacientes de diez a 16 años con diagnóstico de obesidad. Se determinó ácido úrico, perfil de lípidos y grosor de la íntima media carotidea. En el análisis estadístico, se correlacionó el grosor de la íntima media carotídea con los niveles de ácido úrico a través del coeficiente de correlación de Spearman. Resultados: se incluyeron 169 adolescentes con una mediana para la edad de 13 años, sin predominio de sexo. Se identificó una correlación positiva del ácido úrico con el grosor de la íntima media carotídea (r = 0,242, p = 0,001). Al estratificarse de acuerdo con el sexo, no hubo correlación en las mujeres (r = -0,187, p = 0,074), mientras que en los hombres aumentó (r = 0,36, p = 0,001) y por estadio puberal, los adolescentes varones púberes tuvieron una correlación positiva (p = 0,384, p = 0,002). Conclusión: se identificó una correlación positiva débil entre el grosor de la íntima de la carótida y el ácido úrico en adolescentes con obesidad. (AU)

Introduction: obesity in the pediatric population is a public health problem. The correlation of uric acid and carotid intima media thickness in adults has been demonstrated.Objective: to identify the correlation of uric acid and carotid intima media thickness in adolescents with obesity.Material and methods: an observational, cross-sectional study was carried out. Patients aged ten to 16 years with a diagnosis of obesity were included. Uric acid, lipid profile and carotid intima media thickness were determined. In relation to the statistical analysis, carotid intima media thickness was correlated with uric acid levels through Spearman's correlation coefficient. Results: one hundred and sixty-nine adolescents were included with a median age of 13 years, without predominance of sex. A positive correlation of uric acid with carotid intima media thickness was identified (r = 0.242, p = 0.001). When stratified according to sex, there was no correlation in women (r = -0.187, p = 0.074), while in men it increased (r = 0.36, p = 0.001) and by pubertal stage, pubertal male adolescents had a positive correlation (p = 0.384, p = 0.002).Conclusion: a weak positive correlation was identified between carotid intimal thickness and uric acid in obese adolescents. (AU)

[Correlation of uric acid with carotid intima media thickness in obese adolescents]. / Correlación del ácido úrico con el grosor de la íntima media de la carótida en adolescentes con obesidad.

Introduction: Introduction: obesity in the pediatric population is a public health problem. The correlation of uric acid and carotid intima media thickness in adults has been demonstrated. Objective: to identify the correlation of uric acid and carotid intima media thickness in adolescents with obesity. Material and methods: an observational, cross-sectional study was carried out. Patients aged ten to 16 years with a diagnosis of obesity were included. Uric acid, lipid profile and carotid intima media thickness were determined. In relation to the statistical analysis, carotid intima media thickness was correlated with uric acid levels through Spearman's correlation coefficient. Results: one hundred and sixty-nine adolescents were included with a median age of 13 years, without predominance of sex. A positive correlation of uric acid with carotid intima media thickness was identified (r = 0.242, p = 0.001). When stratified according to sex, there was no correlation in women (r = -0.187, p = 0.074), while in men it increased (r = 0.36, p = 0.001) and by pubertal stage, pubertal male adolescents had a positive correlation (p = 0.384, p = 0.002). Conclusion: a weak positive correlation was identified between carotid intimal thickness and uric acid in obese adolescents.

Introducción: Introducción: la obesidad en la población pediátrica es un problema de salud pública. Se ha demostrado la correlación del ácido úrico y el grosor de la íntima media de la carótida en adultos. Objetivo: identificar la correlación del ácido úrico y el grosor de la íntima media de la carótida en adolescentes con obesidad. Material y métodos: se realizó un estudio observacional, transversal. Se incluyeron pacientes de diez a 16 años con diagnóstico de obesidad. Se determinó ácido úrico, perfil de lípidos y grosor de la íntima media carotidea. En el análisis estadístico, se correlacionó el grosor de la íntima media carotídea con los niveles de ácido úrico a través del coeficiente de correlación de Spearman. Resultados: se incluyeron 169 adolescentes con una mediana para la edad de 13 años, sin predominio de sexo. Se identificó una correlación positiva del ácido úrico con el grosor de la íntima media carotídea (r = 0,242, p = 0,001). Al estratificarse de acuerdo con el sexo, no hubo correlación en las mujeres (r = -0,187, p = 0,074), mientras que en los hombres aumentó (r = 0,36, p = 0,001) y por estadio puberal, los adolescentes varones púberes tuvieron una correlación positiva (p = 0,384, p = 0,002). Conclusión: se identificó una correlación positiva débil entre el grosor de la íntima de la carótida y el ácido úrico en adolescentes con obesidad.

Adipokines as predictive factor of cardiac function in pediatric patients with chronic kidney disease.

Background: Adipokines are associated with cardiovascular disease; in chronic kidney disease (CKD) patients adipokines could be useful prognostic factors. Objectives: To explore whether leptin and adiponectin in kidney replacement therapy (KRT) children could have a role on their cardiac function, in the long-term. Design: Prospective cohort study was performed with pediatric KRT patients, aged 8 to 17 years who were undergoing hemodialysis or peritoneal dialysis. At enrollment, lipid profile, adipokines (leptin, leptin receptor, free leptin, and adiponectin), anthropometric measurements and cardiological evaluation were determined. At two-year follow-up, a new cardiological evaluation was performed. Statistical analysis: Quantitative data are presented as median and interquartile range (IQR). Mann-Whitney U test and Chi-squared were used for the between-group comparison. Multivariate analyzes were performed to determine the association of adipokines levels with ventricular ejection fraction (LEVF). Results: We included 56 patients, with a median age of 12.5 years. In the first cardiological evaluation, median LVEF was 70.0% (IQR 61%, 76%), 20 patients (35.7%) had some cardiovascular condition, and 10 (17.8%) altered LVEF. At 24-month follow-up, the median LVEF was 70.5% (IQR 65.1%, 77%), while the delta-LVEF values was 3% (IQR -6.5%, 7%). Delta-LVEF were correlated with baseline adipokines serum levels, and the only positive correlation found was with free leptin (r=0.303, p=0.025). In multivariate analysis, levels of free leptin (Coef. 0.12, p<0.036) and leptin (coef. 1.72, p=0.049), as well as baseline LVEF (Coef. -0.65, p<0.001) were associated with delta-LVEF. Conclusions: Free leptin, leptin and LVEF at the beginning of follow-up were associated with the LVEF decrease at the 24-month follow-up in KRT children.

Leptin/adiponectin ratio as a prognostic factor for increased weight gain in girls with central precocious puberty.

Objective: To determine if the leptin, adiponectin, and leptin/adiponectin ratio (LAR) can predict weight gain at the end of GnRH analogs (GnRHa) treatment in girls with central precocious puberty (CPP). Material and methods: Study design: prospective cohort. Serum levels of leptin and adiponectin were determined at diagnosis of CPP. Anthropometry was performed at diagnosis of CPP and every six-months, until treatment with GnRHa was discontinued and they presented menarche. Patients were divided according to BMI<94 and BMI>95 percentile at diagnosis of CPP. The outcome was the increased in weight gain (e.g., from normal weight to overweight) at the end of follow-up. Statistical analysis: repeated measures ANOVA test and Student's t-test were used to compare groups. Logistic regression analysis was used to evaluate the association of leptin and adiponectin levels, as well as LAR values with increased weight gain. Results: Fifty-six CPP patients were studied, 18 had BMI >95 percentile and 38 BMI <94 percentile. Of the 18 patients who initially had BMI >95th, two patients went from obesity to overweight, while among the 38 patients who started with BMI <94th, 21 (55.2%) increased their weight gain at the end of follow-up. This last group had higher leptin levels (8.99 ± 0.6 vs 6.14 ± 0.8, p=0.005) and higher LAR values compared to those who remained in the same weight (1.3 ± 0.5 vs 0.96 ± 0.56, p=0.01). In the logistic regression analysis, it was found that higher leptin levels and higher LAR values were associated with increased weight gain (RR 1.31, 95%CI 1.03-1.66, RR 4.86, 95%CI 1.10-21.51, respectively), regardless of birth weight, pubertal stage, age, and bone/chronological age ratio. Conclusions: In patients with CPP, leptin levels and higher LAR values appear to be associated with significantly greater weight gain during GhRHa treatment, particularly in girls starting with BMI < 94 percentile.

The leptin/adiponectin ratio as prognostic marker for dyslipidemia during 1 year of follow-up in pediatric patients receiving kidney replacement therapy.

Introduction: Background: leptin and adiponectin are associated with cardiovascular disease in chronic kidney disease (CKD) patients and could be useful prognostic factors. Objectives. to explore the usefulness of the leptin/adiponectin ratio (LAR) to predict the presence or worsening of dyslipidemia during 1 year of follow-up in children receiving kidney replacement therapy (KRT). Material and methods: a prospective cohort study was performed. Pediatric KRT patients aged between 8 and 17 years who were undergoing hemodialysis or peritoneal dialysis were included. At enrollment, the lipid profile, adiponectin and leptin levels, and somatometric measurements, including body fat percentage, were determined. At the one-year follow-up, the lipid profile was reassessed. Results: of the 70 patients included, the median age was 13 years, and there was no sex predominance (52.8 % males). At the end of follow-up, the patients were divided into three groups: those without dyslipidemia (WOD), those who developed or experienced worsening of their dyslipidemia (DWD) and those with persistent dyslipidemia (PD). A LAR > 0.85 (OR, 16.7) and body fat percentage (OR, 1.46) were associated with an increased risk of PD and DWD at 12 months, independently of urea level, BMI Z-score, benzafibrate treatment, CKD progression time, and replacement treatment. Conclusions: a LAR > 0.85 and fat body percentage at the beginning of follow-up were strongly associated with the presence, persistence or worsening of dyslipidemia at the 12-month follow-up in children with KRT.

Introducción: Antecedentes: la leptina y la adiponectina se asocian con enfermedad cardiovascular en los pacientes con enfermedad renal crónica (ERC) y podrían ser factores pronósticos útiles. Objetivos: explorar la utilidad del cociente leptina/adiponectina (LAR) para predecir la presencia o empeoramiento de la dislipidemia durante 1 año de seguimiento en niños que reciben terapia de reemplazo renal (TRR). Material y métodos: se realizó un estudio de cohortes prospectivo. Se incluyeron pacientes pediátricos con TRR de entre 8 y 17 años que estaban en hemodiálisis o diálisis peritoneal. Al inicio del estudio se determinaron el perfil lipídico, los niveles de adiponectina y leptina, y las mediciones somatométricas, incluido el porcentaje de grasa corporal. En el seguimiento de un año, se reevaluó el perfil de lípidos. Resultados: de los 70 pacientes incluidos, la mediana de edad fue de 13 años y no hubo predominio de sexo (52,8 % de varones). Al final del seguimiento, los pacientes se dividieron en tres grupos: aquellos sin dislipidemia (SD), aquellos que desarrollaron o experimentaron un empeoramiento de su dislipidemia (ED) y aquellos con dislipidemia persistente (PD). Un LAR > 0,85 (OR: 16,7) y el porcentaje de grasa corporal (OR: 1,46) se asociaron con un mayor riesgo de ED y PD a los 12 meses, independientemente del nivel de urea, la puntuación Z del IMC, el tratamiento con benzafibrato, el tiempo de progresión de la ERC y el tratamiento de reemplazo. Conclusiones: un LAR > 0,85 y el porcentaje de grasa corporal al inicio del seguimiento se asociaron fuertemente con la presencia, persistencia o empeoramiento de la dislipidemia a los 12 meses de seguimiento en niños con TRR.

The leptin/adiponectin ratio as prognostic marker for dyslipidemia during 1 year of follow-up in pediatric patients receiving kidney replacement therapy / Índice leptina/adiponectina como indicador pronóstico de dislipidemia durante 1 año de seguimiento en pacientes pediátricos que reciben terapia de reemplazo renal

Background: leptin and adiponectin are associated with cardiovascular disease in chronic kidney disease (CKD) patients and could be useful prognostic factors. Objectives: to explore the usefulness of the leptin/adiponectin ratio (LAR) to predict the presence or worsening of dyslipidemia during 1 year of follow-up in children receiving kidney replacement therapy (KRT). Material and methods: a prospective cohort study was performed. Pediatric KRT patients aged between 8 and 17 years who were undergoing hemodialysis or peritoneal dialysis were included. At enrollment, the lipid profile, adiponectin and leptin levels, and somatometric measurements, including body fat percentage, were determined. At the one-year follow-up, the lipid profile was reassessed. Results: of the 70 patients included, the median age was 13 years, and there was no sex predominance (52.8 % males). At the end of follow-up, the patients were divided into three groups: those without dyslipidemia (WOD), those who developed or experienced worsening of their dyslipidemia (DWD) and those with persistent dyslipidemia (PD). A LAR > 0.85 (OR, 16.7) and body fat percentage (OR, 1.46) were associated with an increased risk of PD and DWD at 12 months, independently of urea level, BMI Z-score, benzafibrate treatment, CKD progression time, and replacement treatment. Conclusions: a LAR > 0.85 and fat body percentage at the beginning of follow-up were strongly associated with the presence, persistence or worsening of dyslipidemia at the 12-month follow-up in children with KRT. (AU)

Antecedentes: la leptina y la adiponectina se asocian con enfermedad cardiovascular en los pacientes con enfermedad renal crónica (ERC) y podrían ser factores pronósticos útiles. Objetivos: explorar la utilidad del cociente leptina/adiponectina (LAR) para predecir la presencia o empeoramiento de la dislipidemia durante 1 año de seguimiento en niños que reciben terapia de reemplazo renal (TRR). Material y métodos: se realizó un estudio de cohortes prospectivo. Se incluyeron pacientes pediátricos con TRR de entre 8 y 17 años que estaban en hemodiálisis o diálisis peritoneal. Al inicio del estudio se determinaron el perfil lipídico, los niveles de adiponectina y leptina, y las mediciones somatométricas, incluido el porcentaje de grasa corporal. En el seguimiento de un año, se reevaluó el perfil de lípidos. Resultados: de los 70 pacientes incluidos, la mediana de edad fue de 13 años y no hubo predominio de sexo (52,8 % de varones). Al final del seguimiento, los pacientes se dividieron en tres grupos: aquellos sin dislipidemia (SD), aquellos que desarrollaron o experimentaron un empeoramiento de su dislipidemia (ED) y aquellos con dislipidemia persistente (PD). Un LAR > 0,85 (OR: 16,7) y el porcentaje de grasa corporal (OR: 1,46) se asociaron con un mayor riesgo de ED y PD a los 12 meses, independientemente del nivel de urea, la puntuación Z del IMC, el tratamiento con benzafibrato, el tiempo de progresión de la ERC y el tratamiento de reemplazo. Conclusiones: un LAR > 0,85 y el porcentaje de grasa corporal al inicio del seguimiento se asociaron fuertemente con la presencia, persistencia o empeoramiento de la dislipidemia a los 12 meses de seguimiento en niños con TRR. (AU)

COVID-19 in Neonates with Positive RT-PCR Test. Systematic Review.

BACKGROUND: COVID-19 is an infectious disease of variable severity caused by a new coronavirus. Clinical presentation ranges from asymptomatic cases to severe illness. Most cases in newborns appear to be asymptomatic or mild. OBJECTIVE: To conduct a systematic review of the literature on published studies of COVID-19 in newborns with a positive RT-PCR test. METHODS: The PubMed and EMBASE databases were searched for infection data in newborns from 1 December 2019-21 May 2021. The mesh terms included "SARS-CoV-2", "COVID-19", "novel coronavirus", "newborns" and "neonates". The selection criteria were as follows: original studies reporting clinical, radiological, laboratory, and outcome data in newborns with a positive RT-PCR test for SARS-CoV-2. Two independent investigators reviewed the studies. RESULTS: Seventy-two studies that involved 236 newborns were included. The main clinical manifestations were fever (43.2%), respiratory (46.6%), and gastrointestinal (35.2%) symptoms; 60.1% had mild/moderate disease. A total of 52.5% had a chest X-ray; 43.5% were normal, and 24.1% reported consolidation/infiltration images. The most frequent laboratory abnormalities were elevated C reactive protein and elevated procalcitonin and lymphopenia. Mortality was 1.7%. CONCLUSION: Symptoms of SARS-CoV-2 infection were mild to moderate in most of the newborns. The prognosis was good, and mortality was mainly associated with other comorbidities.

[Usefulness of a nutritional strategy on dyslipidemia in pediatric patients with terminal chronic kidney disease]. / Utilidad de una estrategia nutricional sobre la dislipidemia en pacientes pediátricos con enfermedad renal crónica terminal.

Introduction: Background and objective: in chronic kidney disease (CKD) there are several factors that increase the presence of dyslipidemia. The aim of this study was to identify the usefulness of a nutritional intervention, in children with terminal CKD, on dyslipidemia 6 months after intervention start. Materials and methods: a quasi-experiment study (before and after) was performed. End-stage CKD patients on peritoneal dialysis and hemodialysis were included. Each child underwent a determination somatometry, and lipid profile at the beginning and at 6 months of follow-up. A nutritional guide was made with food traffic lights, turning the food that should be consumed in the least amount possible in red. In addition to including life-size food using educational models. To compare the quantitative variables before and after the intervention, the variables were transformed to their logarithm and a paired Student's t-test was applied. Results: a total of 41 patients were analyzed. After the intervention, the parameters in the lipid profile were modified; meanwhile HDL concentrations increased (41.0 mg/dL vs 44.4 mg/dL, p = 0.048), triglyceride concentrations decreased (227.1 mg/dL vs 185.9 mg/dL, p = 0.007), and these changes persist even after excluding patients who were under lipid-lowering treatment (195 mg/dL vs 171.6, p = 0.049). Regarding the state of dyslipidemia, hypertriglyceridemia decreased, without reaching significance (80.5 % vs 62.5 %, p = 0.073). Conclusions: the nutritional intervention improved HDL and triglyceride concentrations 6 months afterwards in children with terminal CKD.

Introducción: Antecedentes y objetivo: en la enfermedad renal crónica (ERC) existen múltiples factores que incrementan la presencia de la dislipidemia. El objetivo fue identificar la utilidad de una intervención nutricional sobre la dislipidemia, en niños con ERC terminal, a los 6 meses del inicio de la intervención. Materiales y métodos: estudio cuasiexperimental (antes y después). Se incluyeron pacientes con ERC terminal en diálisis peritoneal y hemodiálisis. A cada niño se le realizaron una somatometría y un perfil de lípidos al inicio y a los 6 meses de seguimiento. Se realizó un manual de alimentación con semaforización de los alimentos, poniendo de color rojo los alimentos que se deben consumir en la menor cantidad posible, además de incluir alimentos a tamaño real utilizando modelos educativos. Para comparar las variables cuantitativas antes y después de la intervención se transformaron las variables a su logaritmo y se aplicó la "t" de Student pareada. Resultados: se analizaron 41 pacientes. Posteriormente a la intervención se modificaron los parámetros del perfil lipídico; las concentraciones de HDL se incrementaron (41,0 mg/dL vs. 44,4 mg/dL, p = 0,048), mientras que las concentraciones de triglicéridos disminuyeron (227,1 mg/dL vs. 185.9 mg/dL, p = 0,007), lo cual persiste incluso una vez excluidos aquellos pacientes que se encontraban bajo tratamiento hipolipemiante (195 mg/dL vs. 171,6, p = 0,049). En cuanto al estado de dislipidemia, la hipertrigliceridemia disminuyó sin alcanzar la significancia (80,5 % vs. 62,5 %, p = 0,073). Conclusiones: la intervención nutricional mejoró las concentraciones de HDL y triglicéridos pasados 6 meses de la intervención en niños con ERC terminal.

A Multimodal Strategy to Reduce the Risk of Hospitalization/death in Ambulatory Patients with COVID-19.

BACKGROUND: Different interventions have been implemented worldwide for the house-hold monitoring of patients with mild COVID-19 to reduce the burden of healthcare systems and guarantee quality of care. Telephone follow up and treatment kits have not been evaluated in the context of a national-wide primary care program. AIM OF THE STUDY: To compare the risk of hospitalization and death for COVID-19 between ambulatory patients who received and those who did not receive a treatment kit and telephone follow-up in a developing country METHODS: A two-group comparative analysis was conducted using data from the medical information systems of the Mexican Institute of Social Security. We included a total of 28,048 laboratory-confirmed SARS-CoV-2 patients: 7,898 (28.2%) received a medical kit and 20,150 (71.8%) did not. The incidence rates of hospitalization and death combined were calculated. To identify significant associations between hospitalization or death and treatment medical kits, we calculated the risk ratios using a multivariate logistic model. RESULTS: The incidence of hospitalization was 6.14% in patients who received a kit and 11.71% in those who did not. Male sex, age, and a medical history of obesity, hypertension, diabetes, immunosuppression, or kidney disease were associated with increased risk of hospitalization or death. The risk rates were reduced in patients who received a medical kit or telephone follow-up. In the multivariate model, receiving a medical kit was associated with a lower risk of hospitalization or death from COVID-19: adjusted risk ratio 0.41 (95% confidence interval 0.36-0.47). CONCLUSION: Use of a multimodal strategy may reduce the risk of hospitalization and death in adult outpatients with mild COVID-19.

[Bibliometric analysis of scientific publications on COVID-19 elaborated by staff of the Instituto Mexicano del Seguro Social]. / Análisis bibliométrico de las publicaciones científicas sobre COVID-19 realizadas por personal IMSS.

Background: Since the beginning of the pandemic, new knowledge about COVID-19 obtained by research has been disseminated in medical and scientific journals, but the large number of publications that have been generated in such a short time has been impressive. Objective: To perform a bibliometric analysis of the published articles in medical-scientific journals carried-out by the Mexican Social Security Institute (IMSS) personnel on COVID-19. Material and methods: Systematic review of the literature, identifying the publications included in the PubMed and EMBASE databases, up to September 2022. Articles on COVID-19 were included, in which at least one author had IMSS affiliation; there was no restriction on the type of publication, so original articles, review articles, clinical case reports, etc. were included. The analysis was descriptive. Results: 588 abstracts were obtained, of which 533 full length articles met the selection criteria. Most were research articles (48%), followed by review articles. Mainly clinical or epidemiological aspects were addressed. They were published in 232 different journals, with a predominance of foreign journals (91.8%). Around half of the publications were carried out by IMSS personnel together with authors from other institutions, national or foreign. Conclusions: The scientific contributions prepared by IMSS personnel have contributed to understanding clinical, epidemiological and basic aspects of COVID-19, which has had an impact on improving the quality of care for its beneficiaries.

Introducción: desde el inicio de la pandemia los nuevos conocimientos sobre COVID-19 han sido difundidos en revistas médico-científicas, y ha sido impresionante la gran cantidad de publicaciones que se ha generado en tan poco tiempo. Objetivo: realizar un análisis bibliométrico de los artículos publicados en revistas médico-científicas elaborados por personal del Instituto Mexicano del Seguro Social (IMSS) sobre COVID-19. Material y métodos: revisión sistemática de la literatura, identificando las publicaciones incluidas en las bases de datos PubMed y EMBASE, hasta septiembre de 2022. Se incluyeron los artículos sobre COVID-19 en los que al menos un autor tuviera adscripción IMSS, sin restricción del tipo de publicación, por lo que se incluyeron artículos originales, de revisión, reportes de casos clínicos, etc. El análisis fue de tipo descriptivo. Resultados: se obtuvieron 588 resúmenes, de los cuales 533 artículos cumplieron con los criterios de selección. La mayoría correspondió a artículos de investigación y revisión. Principalmente se abordaron aspectos clínicos o epidemiológicos. Se publicaron en 232 revistas diferentes, predominando revistas extranjeras (91.8%). Alrededor de la mitad de las publicaciones fueron realizadas por personal del IMSS en conjunto con autores de otras instituciones, nacionales o extranjeras. Conclusiones: las aportaciones científicas elaboradas por personal del IMSS han contribuido a conocer aspectos clínicos, epidemiológicos y básicos sobre COVID-19, lo cual ha impactado en la mejora de la calidad de atención de sus derechohabientes.

Screening for COVID-19 in Children Undergoing Elective Invasive Procedures.

OBJECTIVE: To report the frequency of asymptomatic infection with SARS-CoV-2 in pediatric patients undergoing invasive medical procedures in a tertiary pediatric hospital. METHODS: From June to October 2020, a SARS-CoV-2 real-time reverse-transcription polymerase chain reaction (rRT-PCR) test was performed for all pediatric patients scheduled to undergo an elective invasive procedure. None of the patients was symptomatic. The cycle threshold (Ct) values of the ORF1ab gene were recorded for all patients. RESULTS: A total of 700 patients were screened for SARS-CoV-2 infection. The median age was 5.7 y old. In total, 46.6% (n = 326) of the patients were male, and 53.4% (n = 374) were female. The most common underlying diseases were hemato-oncological (25.3%), gastrointestinal (24.9%), and genitourinary (10.3%). The main scheduled surgical-medical procedures were surgical treatment for acquired congenital diseases, biopsy sampling, local therapy administration, organ transplantation, and the placement of central venous catheters, among others. The SARS-CoV-2 rRT-PCR test was positive in 9.4% (66), and the median Ct value was 35.8. None of the patients developed COVID-19. CONCLUSIONS: The frequency of asymptomatic SARS-CoV-2 infection was detected in less than 10% of pediatric patients scheduled to undergo an elective invasive procedure in a tertiary hospital. This frequency is higher than those in reports from different countries.

[Main biases in clinical research]. / Principales sesgos en la investigación clínica.

In developing a research protocol, authors must consider the possible errors that may occur throughout the study. In clinical research, two types of biases are recognized: random errors and systematic errors; the latter are called biases. To date, dozens of biases have been described, which is why the purpose of this article is to describe the main biases that can occur in clinical research studies, as well as strategies to avoid them or to minimize their effects. Since there are several classifications, in order to provide a more practical overview in this review, the biases are grouped into three types: selection biases, information (or performance) biases, and confounding biases. In addition, to make it even more specific, we describe the biases considering the purpose of the research: prognosis, therapeutics, causality, and diagnostic test studies.

En la elaboración de un protocolo de investigación, los autores deben tomar en cuenta los posibles errores que puedan ocurrir a lo largo del estudio. En la investigación clínica se reconocen dos tipos: los errores aleatorios y los errores sistemáticos, estos últimos se denominan sesgos. A la fecha se han descrito decenas de sesgos, por lo que este artículo tiene como objetivo describir los principales sesgos que pueden ocurrir en los estudios de investigación clínica, así como la forma para evitarlos o minimizar sus efectos. En virtud de que existen varias clasificaciones, en la presente revisión y, a fin de disponer un panorama más práctico, los sesgos se agrupan en tres: sesgos de selección, sesgos de información (o ejecución) y sesgos de confusión. Además, para una descripción más específica, se toma en cuenta el propósito del estudio: pronóstico, terapéutica, causalidad y la evaluación de una prueba diagnóstica.

25-Hydroxyvitamin D level is associated with mortality in patients with critical COVID-19: a prospective observational study in Mexico City.

BACKGROUND/OBJECTIVES: Considering the high number of deaths from coronavirus disease 2019 (COVID-19) in Latin American countries, together with multiple factors that increase the prevalence of vitamin D deficiency, we aimed to determine 25-hydroxyvitamin D (25[OH]D) levels and its association with mortality in patients with critical COVID-19. SUBJECTS/METHODS: This was a prospective observational study including adult patients with critical COVID-19. Data, including clinical characteristics and 25(OH)D levels measured at the time of intensive care unit admission, were collected. All patients were followed until hospital discharge or in-hospital death. The patients were divided into those surviving and deceased patient groups, and univariate and multivariate logistic regression analyses were performed to determine independent predictors of in hospital mortality. RESULTS: The entire cohort comprised 94 patients with critical COVID-19 (males, 59.6%; median age, 61.5 years). The median 25(OH)D level was 12.7 ng/mL, and 15 (16%) and 79 (84%) patients had vitamin D insufficiency and vitamin D deficiency, respectively. The median serum 25(OH)D level was significantly lower in deceased patients compared with surviving (12.1 vs. 18.7 ng/mL, P < 0.001). Vitamin D deficiency was present in 100% of the deceased patients. Multivariate logistic regression analysis revealed that age, body mass index, other risk factors, and 25(OH)D level were independent predictors of mortality. CONCLUSIONS: Vitamin D deficiency was present in 84% of critical COVID-19 patients. Serum 25(OH)D was independently associated with mortality in critical patients with COVID-19.

[Statistical methods for effect size analysis]. / Métodos estadísticos para el análisis del tamaño del efecto.

Informing in the studies about the effect size of an intervention or the impact of the factor(s) about an outcome, allows better decision-making for the application of the results in clinical practice. This article presents different methods to analyze the effect size, which can be through direct or indirect statistical methods. Within the direct methods, there's the difference in means between groups and the difference of absolute or relative frequencies. Among the indirect methods, Cohen's "d" family (which are based on standard deviation values), the "r and R2" family, measures of association (e.g. OR, RR, HR), and impact measures (e.g. NNT) are shown. The decision to use any of these methods depends on the objectives of the study and the measuring scale that is used to assess the results, as well as the data distribution. In order to enhance the understanding of the methods described in this article, examples are included, and the need to include level of precision (e.g. confidence intervals) is highlighted, along with the clinical decision thresholds for a better interpretation.

Informar en los estudios sobre el tamaño del efecto de una intervención o del impacto de factor(es) sobre un desenlace, permite tomar mejores decisiones para la aplicación de los resultados a la práctica clínica. En este artículo se presenta la manera de analizar el tamaño del efecto, lo cual puede ser mediante métodos estadísticos directos o indirectos. Dentro de los métodos directos, se encuentra la diferencia de promedios entre grupos y la diferencia de frecuencias absolutas o relativas. Dentro de los métodos indirectos se muestran los índices de la familia de "d" de Cohen (que se basan en valores de desviación estándar), la familia de "r y R2", medidas de asociación (RM, RR, HR) e impacto (NNT). La decisión del uso de cualquiera de los métodos descritos, depende de los objetivos del estudio, la escala de medición usada para evaluar los resultados y la distribución de los datos. Para facilitar la comprensión, se incluyen ejemplos y se resalta la necesidad de incluir los diferentes estadísticos con su nivel de precisión (ej. intervalos de confianza), junto con los umbrales clínicos de decisión, a fin de mejorar su interpretación.

[Risk, association, and impact measures in clinical research studies. How to interpret them for their application in medical care]. / Medidas de riesgo, asociación e impacto en los estudios de investigación clínica. Cómo interpretarlas para su aplicación en la atención médica.

The practice of evidence-based medicine includes the critical analysis of clinical research studies, and, within it, the interpretation of the results reported. In addition, to statistical data, there are estimators that can help clinicians transfer research findings to routine clinical practice. These estimators are measures of risk, association, and impact. Risk measures report current uncertainty or probability (prevalence of a disease, sensitivity, specificity) or for future events (cumulative incidence, incidence density). Measures of association are related to the identification of the risk in order to determine whether certain factors increase or decrease the probability of development of a disease (relative risk, odds ratio, hazard ratio). While measures of impact allow, among other things, to estimate the effect of a treatment (relative risk reduction, absolute risk reduction, number needed to treat). In this review, each of these estimators is described, defined, and presented with examples.

Parte del ejercicio de la medicina basada en evidencia incluye el análisis crítico de los estudios de investigación clínica y dentro de este, la interpretación de los resultados presentados. Además de los datos estadísticos, existen estimadores que pueden ayudar a los clínicos a trasladar los hallazgos de las investigaciones a la práctica clínica habitual. Estos estimadores son las medidas de riesgo, asociación e impacto. Las medidas de riesgo informan sobre la incertidumbre o probabilidad en el presente (prevalencia de una enfermedad, sensibilidad, especificidad) o para eventos futuros (incidencia acumulada, densidad de incidencia). Las medidas de asociación se relacionan con la identificación del riesgo para determinar si ciertos factores aumentan o disminuyen la probabilidad del desarrollo de una enfermedad (riesgo relativo, razón de momios, cociente de riesgo). Mientras que las medidas de impacto permiten, entre otros, estimar el efecto de un tratamiento (reducción del riesgo relativo, reducción del riesgo absoluto, número necesario por tratar). En esta revisión se describen, definen y presentan ejemplos de cada uno de estos estimadores.

Effect of Cataract Surgery on Frequency of Falls among Older Persons: A Systematic Review and Meta-Analysis.

BACKGROUND: Falls are a significant public health problem among older people worldwide. The aim was to perform a new systematic review and meta-analysis to assess whether cataract surgery is effective in reducing the rate of falls in older persons. METHODS: The systematic review was performed following the recommendations by the Cochrane Collaboration. Original papers were included with RCT or quasi-experimental design, which described the effect on uni- or bilateral cataract surgery on the rate of falls among people aged 60 or older. Titles and abstracts were reviewed, full-text versions were retrieved, and two independent examiners reviewed them to assess inclusion criteria. All relevant variables were synthesised in an evidence table. Random-effects meta-analyses were performed pooling the trials, and results were expressed as relative risk (RR) and 95% confidence intervals. RESULTS: The initial search reported 99 potential abstracts, and 41 full-text versions were examined. In the end, eight studies were included. Five included patients 65 years of age and older, two patients 55 years and older, and one included patients 50 years or older. Phacoemulsification and intraocular lens implant were performed in all studies. Two were RCT, and six were quasi-experimental. Falls was the main outcome. The six quasi-experimental studies reported that a reduction in the frequency of falls was observed (RR 0.68, 95% CI 0.48-0.96), although heterogeneity was significant (I 2 = 74%). Only one RCT reported risk reduction of 34% (RR 0.66, 95% CI 0.45-0.96). CONCLUSIONS: This meta-analysis provides evidence that the first cataract surgery reduces the frequency of falls in older people with bilateral cataracts, but a second surgery does not have significant impact.