HYPOCALCEMIA, MORBIDITY, AND MORTALITY IN END-STAGE RENAL-DISEASE

Background: Hypocalcemia and hyperphosphatemia with secondary hyperpar athyroidism are characteristic of end-stage renal disease (ESRD). Alth ough calcium levels critically affect almost all cellular processes, t he impact of chronic hypocalcemia and other abnormalities of calcium-p hosphate homeostatis on the prognosis of ESRD patients is unknown. Met hods: An inception cohort of 433 patients starting ESRD therapy was fo llowed prospectively for an average of 41 months. Serum calcium and ot her parameters were measured monthly. The mean calcium levels were 9.4 +/- 0.7 mg/dl. 23% of the patients had mean calcium levels < 8.8 mg/d l. After adjusting for baseline age, diabetes mellitus, ischemic heart disease, smoking and cholesterol levels, as well as serial albumin, h emoglobin, mean arterial blood pressure, phosphate and alkaline phosph atase levels, chronic hypocalcemia was strongly associated with mortal ity (RR 2.10, p = 0.006 for a mean calcium level < 8.8 mg/dl). The ass ociation with mortality was similar in hemodialysis (RR 2. 10, p = 0.0 06) and peritoneal dialysis patients (2.67, p = 0.034). Using similar covariate adjustment, chronic hypocalcemia was associated with de novo ischemic heart disease (RR 5.23, p < 0.001), recurrent ischemic heart disease (RR 2.46, p = 0.006), de novo cardiac failure (RR 2.64, p < 0 .001), and recurrent cardiac failure (RR 3.30, p < 0.001). Hypocalcemi a retained its independent impact on morbidity and mortality when anal yzed as a time-dependent covariate. Conclusions: Chronic hypocalcemia, a very common, reversible feature of chronic uremia, is independently associated with morbidity and mortality in ESRD patients.