Dietitians' practices in dialysis units in Brazil: nutritional assessment and intervention.

INTRODUCTION: The importance of dietitians in dialysis units is indisputable and mandatory in Brazil, but little is known about the practices adopted by these professionals. OBJECTIVE: To know practices adopted in routine nutritional care, focusing on nutritional assessment tools and treatment strategies for people at risk or diagnosed with malnutrition. METHODOLOGY: Electronic questionnaire disseminated on social media and messaging applications. It included questions that covered dietitians' demographic and occupational profile characteristics and of the dialysis unit, use and frequency of nutritional assessment tools, nutritional intervention strategies in cases of risk or diagnosis of malnutrition, prescription and access to oral supplements. RESULTS: Twenty four percent of the Brazilian dialysis units (n = 207) responded electronically. The most used nutritional assessment tools with or without a pre-established frequency were dietary surveys (96%) and Subjective Global Assessment (83%). The strategies in cases of risk or presence of malnutrition used most frequently (almost always/always) were instructions to increase energy and protein intake from foods (97%), and increasing the frequency of visits (88%). The frequency of prescribing commercial supplements with standard and specialized formulas was quite similar. The availability of dietary supplements by the public healthcare system to patients varied between regions. CONCLUSION: Most dietitians use various nutritional assessment tools and intervention strategies in cases of risk or malnutrition; however, the frequency of use of such tools and strategies varied substantially.

The Effect of Baru (Dypterix alata Vog.) Almond Oil on Markers of Bowel Habits in Hemodialysis Patients.

Gastrointestinal symptoms are common in patients in hemodialysis treatment and were frequently associated with low intake of dietary fibers and liquids, oral iron supplementation, phosphate binders, and low level of physical activity. Thus, the aim of this study was to evaluate the effect of baru almond oil in comparison with mineral oil supplementation on bowel habits of hemodialysis patients. Thirty-five patients on hemodialysis (57% men, 49.9 ± 12.4 years) were enrolled in a 12-week single-blind clinical trial. Patients were allocated (1 : 2) by sex and age into (1) the mineral group: 10 capsules per day of mineral oil (500 mg each) or (2) the baru almond oil group: 10 capsules per day of baru almond oil (500 mg each). Bowel habits were assessed by the Rome IV criteria, Bristol scale, and self-perception of constipation. Food consumption, physical activity level, and time spent sitting were also evaluated at the baseline and at the end of the study. After 12 weeks of supplementation, the baru almond oil group showed reduced Rome IV score (6.1 ± 5.5 vs 2.8 ± 4.3, p=0.04) and the straining on the evacuation score (1.2 ± 1.4 vs 0.4 ± 0.7; p=0.04), while the mineral group did not show any change in the parameters. The frequency of self-perception of constipation was lower in the baru almond oil group after intervention (45.0% vs 15.0%, p=0.04). Baru almond oil improved bowel habit and the straining on evacuation in hemodialysis patients.

The 2020 Updated KDOQI Clinical Practice Guidelines for Nutrition in Chronic Kidney Disease.

Over the last 2 decades, there has been a great accumulation of new evidence regarding the management of nutritional and metabolic aspects of kidney disease. The 2020 update to the KDOQI Clinical Practice Guideline for Nutrition in CKD provides a comprehensive up-to-date information on the understanding and care of patients with CKD. It provides updated information on nutritional aspects of kidney disease for the practicing clinician and allied health-care workers. The current manuscript provides an overview of the updated guideline statements on major subjects including nutritional assessment, dietary protein and energy intake, nutritional supplementation, micronutrients, and electrolytes. The guidelines are focused on dietary management rather than all possible nutritional interventions.

Does dietary potassium intake associate with hyperkalemia in patients with chronic kidney disease?

BACKGROUND: Dietary potassium restriction is a strategy to control hyperkalemia in chronic kidney disease (CKD). However, hyperkalemia may result from a combination of clinical conditions. This study aimed to investigate whether dietary potassium or the intake of certain food groups associate with serum potassium in the face of other risk factors. METHODS: We performed a cross-sectional analysis including a nondialysis-dependent CKD (NDD-CKD) cohort and a hemodialysis (HD) cohort. Dietary potassium intake was assessed by 3-day food records. Underreporters with energy intake lower than resting energy expenditure were excluded. Hyperkalemia was defined as serum potassium >5.0 mEq/L. RESULTS: The NDD-CKD cohort included 95 patients {median age 67 [interquartile range (IQR) 55-73] years, 32% with diabetes mellitus (DM), median estimated glomerular filtration rate 23 [IQR 18-29] mL/min/1.73 m2} and the HD cohort included 117 patients [median age 39 (IQR 18-67) years, 50% with DM]. In NDD-CKD, patients with hyperkalemia (36.8%) exhibited lower serum bicarbonate and a tendency for higher serum creatinine, a higher proportion of DM and the use of renin-angiotensin-aldosterone system blockers, but lower use of sodium bicarbonate supplements. No association was found between serum and dietary potassium (r = 0.01; P = 0.98) or selected food groups. Conditions associated with hyperkalemia in multivariable analysis were DM {odds ratio [OR] 3.55 [95% confidence interval (CI) 1.07-11.72]} and metabolic acidosis [OR 4.35 (95% CI 1.37-13.78)]. In HD, patients with hyperkalemia (50.5%) exhibited higher serum creatinine and blood urea nitrogen and lower malnutrition inflammation score and a tendency for higher dialysis vintage and body mass index. No association was found between serum and potassium intake (r = -0.06, P = 0.46) or food groups. DM [OR 4.22 (95% CI 1.31-13.6)] and serum creatinine [OR 1.50 (95% CI 1.24-1.81)] were predictors of hyperkalemia in multivariable analyses. CONCLUSIONS: Dietary potassium was not associated with serum potassium or hyperkalemia in either NDD-CKD or HD patients. Before restricting dietary potassium, the patient's intake of potassium should be carefully evaluated and other potential clinical factors related to serum potassium balance should be considered in the management of hyperkalemia in CKD.

Effects of baru almond oil (Dipteryx alata Vog.) supplementation on body composition, inflammation, oxidative stress, lipid profile, and plasma fatty acids of hemodialysis patients: A randomized, double-blind, placebo-controlled clinical trial.

BACKGROUND: The consumption of nuts and edible seeds is associated with the improvement of the metabolic profile and reduction of cardiovascular diseases. However, the effects of its subproducts, such as oil, are still poorly studied. This study aimed to evaluate the effect of the baru almond oil supplementation on inflammation, oxidative stress, body composition, lipid profile, and plasma fatty acids of hemodialysis patients. METHODS: In a randomized, double-blind, 12-week placebo-controlled clinical study, hemodialysis patients were supplemented with 5 g of baru oil (BG, n = 17) or 5 g of mineral oil (placebo, BP, n = 12). Body composition, renal function, ultra-sensitive C-reactive protein (us-CRP), oxidative stress, plasma fatty acids, and lipid profile were analysed before and after the intervention. RESULTS: Patients were aged 50.5 ±â€¯2.2 years and the average time of dialyses was 52,1 ±â€¯42,6 months. The BG decreased us-CRP concentration compared to PG (-1.2 ±â€¯0.2 vs. + 0.8 ±â€¯0.2 mg / L,d = 0.88; p =  0.01). Baru almond oil supplementation was not effective in improving body composition, lipid profile, and oxidative stress. CONCLUSION: Baru almond oil supplementation decreased us-CRP concentration in patients with chronic kidney disease under hemodialysis treatment.

KDOQI Clinical Practice Guideline for Nutrition in CKD: 2020 Update

The National Kidney Foundation's Kidney Disease Outcomes Quality Initiative (KDOQI) has provided evidence-based guidelines for nutrition in kidney diseases since 1999. Since the publication of the first KDOQI nutrition guideline, there has been a great accumulation of new evidence regarding the management of nutritional aspects of kidney disease and sophistication in the guidelines process. The 2020 update to the KDOQI Clinical Practice Guideline for Nutrition in CKD was developed as a joint effort with the Academy of Nutrition and Dietetics (Academy). It provides comprehensive up-to-date information on the understanding and care of patients with chronic kidney disease (CKD), especially in terms of their metabolic and nutritional milieu for the practicing clinician and allied health care workers. The guideline was expanded to include not only patients with end-stage kidney disease or advanced CKD, but also patients with stages 1-5 CKD who are not receiving dialysis and patients with a functional kidney transplant. The updated guideline statements focus on 6 primary areas: nutritional assessment, medical nutrition therapy (MNT), dietary protein and energy intake, nutritional supplementation, micronutrients, and electrolytes. The guidelines primarily cover dietary management rather than all possible nutritional interventions. The evidence data and guideline statements were evaluated using Grading of Recommendations, Assessment, Development and Evaluation (GRADE) criteria. As applicable, each guideline statement is accompanied by rationale/background information, a detailed justification, monitoring and evaluation guidance, implementation considerations, special discussions, and recommendations for future research.

KDOQI Clinical Practice Guideline for Nutrition in CKD: 2020 Update.

The National Kidney Foundation's Kidney Disease Outcomes Quality Initiative (KDOQI) has provided evidence-based guidelines for nutrition in kidney diseases since 1999. Since the publication of the first KDOQI nutrition guideline, there has been a great accumulation of new evidence regarding the management of nutritional aspects of kidney disease and sophistication in the guidelines process. The 2020 update to the KDOQI Clinical Practice Guideline for Nutrition in CKD was developed as a joint effort with the Academy of Nutrition and Dietetics (Academy). It provides comprehensive up-to-date information on the understanding and care of patients with chronic kidney disease (CKD), especially in terms of their metabolic and nutritional milieu for the practicing clinician and allied health care workers. The guideline was expanded to include not only patients with end-stage kidney disease or advanced CKD, but also patients with stages 1-5 CKD who are not receiving dialysis and patients with a functional kidney transplant. The updated guideline statements focus on 6 primary areas: nutritional assessment, medical nutrition therapy (MNT), dietary protein and energy intake, nutritional supplementation, micronutrients, and electrolytes. The guidelines primarily cover dietary management rather than all possible nutritional interventions. The evidence data and guideline statements were evaluated using Grading of Recommendations, Assessment, Development and Evaluation (GRADE) criteria. As applicable, each guideline statement is accompanied by rationale/background information, a detailed justification, monitoring and evaluation guidance, implementation considerations, special discussions, and recommendations for future research.

Diet in Chronic Kidney Disease: an integrated approach to nutritional therapy.

A healthy diet is an essential requirement to promote and preserve health, even in the presence of diseases, such as chronic kidney disease (CKD). In this review, nutritional therapy for CKD will be addressed considering not only the main nutrients such as protein, phosphorus, potassium, and sodium, which require adjustments as a result of changes that accompany the reduction of renal functions, but also the benefits of adopting dietary patterns associated with better outcomes for both preventing and treating CKD. We will also emphasize that these aspects should also be combined with a process of giving new meaning to a healthy diet so that it can be promoted. Finally, we will present the perspective of an integrated approach to the individual with CKD, exploring the importance of considering biological, psychological, social, cultural, and economic aspects. This approach has the potential to contribute to better adherence to treatment, thus improving the patient's quality of life.

Diet in Chronic Kidney Disease: an integrated approach to nutritional therapy

SUMMARY A healthy diet is an essential requirement to promote and preserve health, even in the presence of diseases, such as chronic kidney disease (CKD). In this review, nutritional therapy for CKD will be addressed considering not only the main nutrients such as protein, phosphorus, potassium, and sodium, which require adjustments as a result of changes that accompany the reduction of renal functions, but also the benefits of adopting dietary patterns associated with better outcomes for both preventing and treating CKD. We will also emphasize that these aspects should also be combined with a process of giving new meaning to a healthy diet so that it can be promoted. Finally, we will present the perspective of an integrated approach to the individual with CKD, exploring the importance of considering biological, psychological, social, cultural, and economic aspects. This approach has the potential to contribute to better adherence to treatment, thus improving the patient's quality of life.

RESUMO Uma dieta saudável é essencial para promover e preservar a saúde, mesmo na presença de doenças como a Doença Renal Crônica (DRC). Nesta revisão, a terapia nutricional para pacientes de DRC será abordada levando em conta não só os principais nutrientes que precisam ser ajustados devido às alterações que acompanham a redução das funções renais, tais como proteínas, fósforo, potássio e sódio. Abordaremos também os benefícios da adoção de padrões alimentares associados a desfechos melhores tanto para a prevenção quanto para o tratamento da DRC. Também enfatizaremos que esses aspectos devem ser aliados a um processo de ressignificação do conceito de dieta saudável para que seja possível a sua promoção. Por último, apresentaremos a perspectiva de uma abordagem integrada para o indivíduo com DRC, explorando a importância de considerar aspectos biológicos, psicológicos, sociais, culturais e econômicos. Essa abordagem tem o potencial de contribuir para uma melhor adesão ao tratamento, melhorando assim a qualidade de vida do paciente.

The Effect of Long-Term Cholecalciferol Supplementation on Vascular Calcification in Chronic Kidney Disease Patients With Hypovitaminosis D.

OBJECTIVE: The role of vitamin D supplementation on vascular calcification (VC) in patients with chronic kidney disease (CKD) is controversial. The objective of this study was to evaluate the effects of long-term cholecalciferol supplementation on VC in nondialysis patients with CKD stages 3-4 with hypovitaminosis D. DESIGN AND METHODS: Eighty patients aged 18-85 years with creatinine clearance between 15 and 60 mL/min/1.73 m2 and serum 25(OH)D level < 30 ng/mL were enrolled in a 18-month prospective study. Individuals with vitamin D insufficiency (25-hydroxyvitamin D [25(OH)D] level between 16 and 29 ng/mL) were included in a randomized, double-blind, two-arm study to receive cholecalciferol or placebo. Patients with vitamin D deficiency [25(OH)D < 15 ng/mL] were included in an observational study and mandatorily received cholecalciferol. The coronary artery calcium score was obtained by multislice computed tomography at baseline and the 18th month. RESULTS: During the study, VC did not change in the treated insufficient group (418 [81-611] to 364 [232-817] AU, P = 0.25) but increased in the placebo group (118 [37-421] to 199 [49-490] AU, P = 0.01). The calcium score change was inversely correlated with 25(OH)D change (r = -0.45; P = 0.037) in the treated insufficient group but not in the placebo group. Renal function did not change in the insufficient, treated, and placebo groups. In multivariate analysis, there was no difference in VC progression between the treated and placebo insufficient groups (interaction P = 0.92). In the deficient group, VC progressed (265 [84-733] to 333 [157-745] AU; P = 0.006) and renal function declined (33 [26-43] to 23 [17-49] mL/min/1.73 m2; P = 0.04). The calcium score change was inversely correlated with cholecalciferol cumulative doses (r = -0.41; P = 0.048) and kidney function change (r = -0.43; P = 0.033) but not with 25(OH)D change (r = -0.08; P = 0.69). CONCLUSION: Vitamin D supplementation did not attenuate VC progression in CKD patients with hypovitaminosis D. CONCLUSION: Vitamin D supplementation did not attenuate VC progression in CKD patients with hypovitaminosis D.

Cholecalciferol Supplementation Did Not Change Interleukin-7 and B cell-Activating Factor Levels and CD95 Expression in B lymphocytes in Patients on Dialysis: A Randomized Pilot-Controlled Trial.

BACKGROUND: End-stage renal disease results in B cell lymphopenia and low levels of vitamin D. Since the link between vitamin D deficiency and B lymphocytes dysfunction are not clear in patients with end-stage renal disease, we suggest that vitamin D adequacy and factors related to the homeostasis of these cells should be investigated. B lymphocytes homeostasis is a process mainly regulated signals of grown and death as interleukin (IL)-7, B cell-activating factor (BAFF)/BAFF-receptor and CD95 expression. OBJECTIVE: As vitamin D serum levels were reduced in patients with end stage renal disease and it is associated with human B homeostasis, we evaluated the effect of cholecalciferol supplementation on dialysis. DESIGN: Randomized, double blind clinical trial in dialysis patients with 25OH Vitamin D deficiency for a period of 12 weeks. MAIN OUTCOME MEASURE: In a pilot study, we investigated the effect of cholecalciferol supplementation (100,000 UI once per week or placebo. In vitro, peripheral blood mononuclear cells isolated by Ficoll-Hypaque centrifugation from 12 healthy volunteers were incubated with healthy or uremic serum in the presence or absence of 25 (OH)DC with 5% CO. RESULTS: There was an increase in the serum 25(OH)D level in the cholecalciferol group. No differences were found in BAFF and IL7 levels and CD95 and BAFF-R expression in B lymphocytes from patients on dialysis after cholecalciferol supplementation. Uremic serum induced an increase in the IL-7, BAFF, BAFF-R and CD95 expression compared with the control. However, we observed no effect of incubation of 25(OH)D3 and 1,25(OH)2D3 on the expression of IL-7, BAFF, BAFF-R and CD95 when incubated in the presence of normal or uremic serum. CONCLUSION: Our results suggest that vitamin D is not involved in mechanisms of regulation of differentiation and survival in B lymphocytes. In conclusion, further studies are needed to explore the effects of vitamin D on B lymphocytes to better evaluate the possible impact of vitamin D on humoral response in the CKD population.

Cholecalciferol decreases inflammation and improves vitamin D regulatory enzymes in lymphocytes in the uremic environment: A randomized controlled pilot trial.

It has been reported that vitamin D regulates the immune system. However, whether vitamin D repletion modulates inflammatory responses in lymphocytes from dialysis patients is unclear. In the clinical trial, thirty-two (32) dialysis patients with 25 vitamin D ≤ 20ng/mL were randomized to receive either supplementation of cholecalciferol 100,000 UI/week/3 months (16 patients) or placebo (16 patients). In the in vitro study, B and T lymphocytes from 12 healthy volunteers (HV) were incubated with or without uremic serum in the presence or absence of 25 or 1,25 vitamin D. We evaluated the intracellular expression of IL-6, IFN-γ TLR7, TLR9, VDR, CYP27b1 and CYP24a1 by flow cytometry. We observed a reduction in the expression of TLR7, TLR9, INF-γ and CYP24a1 and an increase in VDR and CYP27b1 expression in patients which were supplemented with cholecalciferol, whereas no differences were found in the placebo group. Uremic serum increased the intracellular expression of IL-6, IFN-γ, TLR7, TLR9, VDR, CYP27b1 and CYP24a1. Treatment with 25 or 1,25 vitamin D decreased IL-6 and TLR9. CYP24a1 silencing plus treatment with 25 and/or 1,25 vitamin D had an additional reduction effect on IL-6, IFN-γ, TLR7 and TLR9 expression. This is the first study showing that cholecalciferol repletion has an anti-inflammatory effect and improves vitamin D intracellular regulatory enzymes on lymphocytes from dialysis patients.

The short-term effects of olive oil and flaxseed oil for the treatment of constipation in hemodialysis patients.

OBJECTIVES: To evaluate the effects of olive oil and flaxseed oil compared with mineral oil for the treatment of constipation in patients undergoing hemodialysis. METHODS: A 4-week, double-blind, randomized, and controlled trial was conducted. Fifty constipated patients (29% male, 51 ± 12 years) diagnosed by the Rome III criteria were randomly assigned to receive mineral oil (control group; n = 17), olive oil (n = 16), or flaxseed oil (n = 17). The initial oil dose was 4 mL/day, and adjustments during the follow-up could be made as needed. The impact of the intervention was assessed by the Rome III criteria scores. RESULTS: The most frequent symptoms of constipation evaluated by the Roma III criteria at baseline were comparable among the groups and included "incomplete evacuation" (92%), "lumpy or hard stools," (72%) and "anorectal obstruction" (70%). The Rome III score improved significantly in patients receiving mineral oil (10.5 ± 5.0 to 4.1 ± 4.0; P < .01), olive oil (10.3 ± 4.2 to 3.2 ± 3.8; P = .01), and flaxseed oil (9.6 ± 4.2 to 6.0 ± 5.1; P < .01), with no significant group-by-time interaction (P = .15). The scores of 5 from 6 constipation symptoms reduced similarly in the mineral oil and olive oil groups, whereas only the frequency of evacuation and the consistency of stools improved in the flaxseed oil group. CONCLUSIONS: We demonstrated that the daily use of olive oil or flaxseed oil was as effective as mineral oil in the treatment of constipation in patients undergoing hemodialysis.

Cholecalciferol supplementation in chronic kidney disease: restoration of vitamin D status and impact on parathyroid hormone.

BACKGROUND/AIMS: Hypovitaminosis D is highly prevalent among patients with chronic kidney disease (CKD) and has been associated with poor outcome. We aimed to test the effect of a protocol of cholecalciferol supplementation on the restoration of vitamin D status and on parathyroid hormone (PTH) levels in patients with CKD. METHODS: This was a prospective interventional study of 6 months. Forty-five CKD patients (stages 3 and 4) with 25-hydroxyvitamin D deficiency [25(OH)D <15 ng/ml] were included. Patients received a weekly dose of 50,000 IU of cholecalciferol during 3 months, and 50,000 IU/month thereafter for those who had achieved 25(OH)D ≥30 ng/ml. RESULTS: At 3 months, 78% of the patients restored their vitamin D status. At 6 months, only 43% of those patients maintained adequate vitamin D status. PTH decreased at 3 months (p = 0.02) but returned to baseline levels after 6 months. Fibroblast growth factor 23 increased at 3 months (p = 0.001) and returned to initial levels at 6 months. No changes were found in serum 1,25(OH)(2)D, ionized calcium and phosphorus. CONCLUSIONS: A weekly dose of 50,000 IU of cholecalciferol for 3 months restored the vitamin D status of most patients and led to a reduction in PTH. The monthly dose of 50,000 IU appears not to be sufficient to maintain the levels of 25(OH)D.

Risk factors for hypovitaminosis D in nondialyzed chronic kidney disease patients.

BACKGROUND: Hypovitaminosis D is highly prevalent among patients with chronic kidney disease and has been associated with worse outcome even in the earlier stages of the disease. OBJECTIVE: This study aimed to investigate the risk factors for hypovitaminosis D in nondialyzed patients with chronic kidney disease. DESIGN: This cross-sectional study included 120 patients with chronic kidney disease at stages 2 to 5 (62% male, age: 55.4 ± 11.3 year, estimated glomerular filtration rate: 35.1 ± 15 mL/minute, body mass index [BMI]: 27.1 ± 5.2 kg/m(2), 31% diabetics). Serum 25-hydroxivitamin D [25(OH)D] was measured by chemiluminescence. Subjective global assessment, total body fat (dual-energy X-ray absorptiometry), visceral and subcutaneous abdominal fat (computed tomography), and several laboratory parameters were assessed. RESULTS: Insufficiency of 25(OH)D (15 to 30 ng/mL) was observed in 55% and deficiency (<15 ng/mL) in 20% of the patients. Patients with diabetes, BMI ≥30 kg/m(2), and who had the blood collection during the winter or spring had lower levels of 25(OH)D. Serum 25(OH)D correlated inversely with parathyroid hormone, proteinuria, insulin resistance, leptin, and subcutaneous abdominal fat. The risk factors for hypovitaminosis D were diabetes (odds ratio: 3.8; 95% CI: 1.2 to 11.7; P = .022) and BMI ≥30 kg/m(2) (odds ratio: 4.3; 95% CI: 1.2 to 15.3; P = .018). In the logistic regression analysis adjusting for gender, skin color, and season of the year, diabetes and BMI ≥30 kg/m(2) were independently associated with hypovitaminosis D. CONCLUSIONS: Diabetes and obesity were the risk factors for hypovitaminosis D in nondialyzed patients with chronic kidney disease. Effective interventional protocols of vitamin D supplementation taking into account these risk factors are warranted for this population.

Hypovitaminosis D in chronic kidney disease patients: prevalence and treatment.

In the past decade, there has been accumulating evidence indicating that vitamin D may provide great health benefits. Indeed, it has been shown that vitamin D deficiency not only causes bone and mineral disturbances but also may increase the risk of many common chronic diseases. Since very few foods contain vitamin D, humans depend on sun exposure to satisfy their requirements for vitamin D. However, factors related to the location, climate, aging, skin pigmentation, and use of barriers to protect from the sun light contribute to limit the synthesis of vitamin D in the skin. Vitamin D deficiency is highly prevalent in the general population and even more common in patients with chronic kidney disease (CKD). Certain conditions associated with CKD such as protein losses and the decreased food intake can predispose these patients to hypovitaminosis D. The interest in the nutritional status of vitamin D of CKD patients has been renewed after the recognition that low circulating levels of 25 hydroxyvitamin D, and not only of the vitamin D active form (1,25 dihydroxyvitamin D), can contribute to the development of secondary hyperparathyroidism. Therefore, vitamin D supplementation with either ergocalciferol or cholicalciferol has been recommended to restore and maintain adequate vitamin D status in CKD.

Vitamin D status of chronic kidney disease patients living in a sunny country.

BACKGROUND: Vitamin D nutritional status has been poorly investigated in chronic kidney disease (CKD) patients, especially those inhabiting a subtropical area where the sunlight incidence is abundant all year. OBJECTIVE: The purpose of this study was to evaluate the status of vitamin D and to analyze the relationship of circulating 25-hydroxyvitamin D [25(OH)D] with other serum parameters of mineral metabolism in patients with CKD not yet on dialysis. DESIGN: This cross-sectional study enrolled 144 nondiabetic CKD patients not yet receiving dialysis (stages 2 to 5 of CKD). Fasting blood samples were obtained for measurements of 25-hydroxyvitamin D [25(OH)D], 1,25-dihydroxyvitamin D [1,25(OH)(2)D], intact parathyroid hormone, phosphorus, and calcium. RESULTS: In the entire sample, the serum concentration of 25(OH) was 34.3 +/- 18.3 ng/mL (+/-SD unless otherwise noted). A deficiency of vitamin D, i.e., 25(OH)D <15 ng/mL, was found in only one patient. Fifty-seven patients (39.6%) were considered vitamin D-insufficient (16 to 30 ng/mL). The vitamin D-insufficient group contained more females, a higher degree of proteinuria, and a lower serum concentration of 1,25(OH)(2)D. In multiple regression analysis, 25(OH)D was associated positively with 1,25(OH)(2)D, serum calcium, and proteinuria, whereas 1,25(OH)(2)D was associated only with 25(OH)D and phosphorus. The variables associated with intact parathormone were serum phosphorus and creatinine clearance, but not 1,25(OH)(2)D or 25(OH)D. CONCLUSION: Despite an elevated prevalence of vitamin D insufficiency, the serum concentration of 25(OH)D was, on average, higher than that found in patients inhabiting higher-latitude regions. This higher serum concentration may have contributed to the differences found in the relationship between vitamin D metabolites and other serum markers of mineral metabolism in our CKD patients.