A low plasma 1,25(OH)2 vitamin D/PTH (1-84) ratio predicts worsening of renal function in patients with chronic heart failure

Background: Dysregulation of the vitamin D system promotes renal dysfunction and has direct detrimental effects on the heart. Progressive deterioration of renal function is common in patients with chronic heart failure (HF) and is invariably associated with unfavorable outcomes which can be improved by early identification and timely interventions. We examined the relation between two plasma markers of vitamin D metabolism and worsening of renal function (WRF) in a large cohort of patients with chronic HF. Methods: Plasma levels of 1,25-dihydroxyvitamin D (1,25(OH)(2)D) and parathyroid hormone PTH (1-84) were measured in 1237 patients with clinical evidence of chronic and stable HF enrolled in the multicentre GISSI-HF trial and followed for 3.9 years. We examined the relation of 1,25(OH)(2)D, PTH(1-84), and their ratio with WRF, defined as first increase in serum creatinine concentration >= 0.3 mg/dL and >= 25% at two consecutive measurements at any time during the study. Results: Lower 1,25(OH)(2)D/PTH(1-84) ratio was associated with a higher baseline serum concentration of creatinine, winter season, female sex and older age; 335 patients (29.6%) experienced an episode of WRF. After adjustment, a lower 1,25(OH)(2)D/PTH(1-84) ratio remained significantly associated with a higher risk of WRF (HR = 0.75 [0.62-0.90], p = 0.002) and correctly reclassified events. This ratio also independently predicted mortality and admission to hospital for cardiovascular reasons. Conclusions: The plasma 1,25(OH)(2)D/PTH(1-84) ratio is a promising indicator of future risk of deterioration of renal function in patients with chronic HF and mild renal impairment, that may serve to optimize therapies and improve outcomes. (C) 2016 Elsevier Ireland Ltd. All rights reserved.