Vitamine D et rein

Le calcitriol et ses analogues inhibent le système rénineangiotensine- aldostérone, qui joue un rôle important dans le développement des lésions glomérulaires et tubulo-interstitielles et dans l’apparition de la protéinurie, mais aussi l’activation de la voie NF-kB qui est connue pour favoriser la maladie rénale chronique en stimulant l’inflammation et la fibrogenèse. Les effets pléiotropes de la vitamine D sont également très intéressants pour le patient insuffisant rénal (diminution de la mortalité, de la protéinurie et effets anti-inflammatoires). De plus, l’administration de vitamine D native (cholécalciférol ou ergocalciférol) diminue les concentrations sériques de parathormone. La supplémentation en vitamine D native chez l’insuffisant rénal n’entraîne pas de toxicité ni d’augmentation du risque de calcification vasculaire malgré les effets hypercalcémiants et hyperphosphorémiants de cette molécule sous sa forme active. La vitamine D per se (c’est-à-dire sans apports calciques excessifs), aux doses habituellement utilisées en clinique, n’est pas associée à une augmentation du risque de lithiase urinaire. Dans le domaine de la transplantation rénale, les études expérimentales montrent un rôle protecteur des analogues de la vitamine D contre le rejet aigu, mais les études cliniques restent à ce jour principalement observationnelles

Contemporary rates and predictors of fast progression of chronic kidney disease in adults with and without diabetes mellitus

Abstract Background Chronic kidney disease (CKD) is highly prevalent but identification of patients at high risk for fast CKD progression before reaching end-stage renal disease in the short-term has been challenging. Whether factors associated with fast progression vary by diabetes status is also not well understood. We examined a large community-based cohort of adults with CKD to identify predictors of fast progression during the first 2 years of follow-up in the presence or absence of diabetes mellitus. Methods Within a large integrated healthcare delivery system in northern California, we identified adults with estimated glomerular filtration rate (eGFR) 30–59 ml/min/1.73 m2 by CKD-EPI equation between 2008 and 2010 who had no previous dialysis or renal transplant, who had outpatient serum creatinine values spaced 10–14 months apart and who did not initiate renal replacement therapy, die or disenroll during the first 2 years of follow-up. Through 2012, we calculated the annual rate of change in eGFR and classified patients as fast progressors if they lost > 4 ml/min/1.73 m2 per year. We used multivariable logistic regression to identify patient characteristics that were independently associated with fast CKD progression stratified by diabetes status. Results We identified 36,195 eligible adults with eGFR 30–59 ml/min/1.73 m2 and mean age 73 years, 55% women, 11% black, 12% Asian/Pacific Islander and 36% with diabetes mellitus. During 24-month follow-up, fast progression of CKD occurred in 23.0% of patients with diabetes vs. 15.3% of patients without diabetes. Multivariable predictors of fast CKD progression that were similar by diabetes status included proteinuria, age ≥ 80 years, heart failure, anemia and higher systolic blood pressure. Age 70–79 years, prior ischemic stroke, current or former smoking and lower HDL cholesterol level were also predictive in patients without diabetes, while age 18–49 years was additionally predictive in those with diabetes. Conclusions In a large, contemporary population of adults with eGFR 30–59 ml/min/1.73 m2, accelerated progression of kidney dysfunction within 2 years affected ~ 1 in 4 patients with diabetes and ~ 1 in 7 without diabetes. Regardless of diabetes status, the strongest independent predictors of fast CKD progression included proteinuria, elevated systolic blood pressure, heart failure and anemia