[Clinical and biochemical characteristics of predialysis patients in terms of 25 hydroxy vitamin D levels]. / Características clínicas y bioquímicas de pacientes en prediálisis con respecto a los niveles de 25 hidroxivitamina D.

ABSTRACT

INTRODUCTION: Decreased levels of 25 hydroxyvitamin D (25[OH]D) have been reported in patients with chronic kidney disease (CKD). The pleiotropic effects of vitamin D are known to go beyond mineral metabolism. OBJECTIVES: The aims of this study were to 1) Determine the 25(OH)D levels in predialysis outpatients. 2) Find out the clinical and biochemical characteristics of patients with 25(OH)D deficiency, and predictive factors for the deficiency. PATIENTS AND METHODS: An observational study in 79 predialysis outpatients was performed. Clinical and biochemical parameters were analysed in terms of nutrition, inflammation and mineral metabolism in relation to serum levels of 25(OH)D. Levels of 25(OH)D lower than 15ng/ml were considered to be deficient. RESULTS: Serum levels of 25(OH)D were deficient in 41 patients (52%). The comparative study regarding levels of vitamin 25(OH)D showed the group of patients with a deficiency, i.e. those with less than 15ng/ml, were older (70 ± 11.97 vs. 61 ± 14.5; p = 0.005), had a greater body mass index, BMI, (30±4.06 vs. 27.1 ± 5.08; p = 0.003) and increased proteinuria (1.42g/24h (0.53-2.96) vs. 0.51 (0.20-1.48), p = 0.009). This group included a greater number of diabetic patients 20 (76.9%) vs. 6 (23%), p = 0.002. They had a higher level of parathyroid hormone (PTH) 359 (239-658) vs. 233 (129-323), p = 0.000; and more patients were under treatment with Calcitriol 28 (62.2%) vs. 17 (37.8%), p = 0.024. In the multivariate analysis, high levels of PTH (OR 13.38; CI 95% [2.94-60.89]; p=0.001), increased proteinuria (OR 4.41; CI 95% [1.12-17.25]; p = 0.033); and being diabetic (OR 5.713; CI 95% [1.43-22.77]; p = 0.014) were independent predictor factors for patients with 25(OH)D deficiency. CONCLUSIONS: In our study, we observed a high prevalence of 25(OH)D deficiency among patients with CKD. The increased levels of PTH, the increase of proteinuria and the presence of diabetes were independent predictors for 25(OH)D deficiency.