Risk factors and mortality associated with calciphylaxis in end-stage renal disease

Background. We conducted a case control study to determine risk factors and mortality associated with calciphylaxis in endstage renal disease. Methods. Cases of calciphylaxis diagnosed between December 1989 and January 2000 were identified. Three controls were identified for each hemodialysis patient, with calciphylaxis matched to the date of initiation of hemodialy sis. Laboratory data and medication doses were recorded during the 12 month s prior to the date of diagnosis and at the time of diagnosis of calciphyla xis. Conditional logistic regression was used to identify risk factors for calciphylaxis. Cox proportional hazards models were used to estimate the ri sk of death associated with calciphylaxis. Results. Nineteen cases and 54 controls were identified. Eighteen patients were hemodialysis patients, and one had a functioning renal allograft. Diag nosis was confirmed by skin biopsy in 16 cases. Women were at a sixfold hig her risk of developing calciphylaxis (OR = 6.04, 95% CI 1.62 to 22.6, P = 0 .007). There was a 21% lower risk of calciphylaxis associated with each 0.1 g/dL increase in the mean serum albumin during the year prior to diagnosis and at the time of diagnosis of calciphylaxis (OR = 0.79. 95% CI. 0.64 to 0.99. P = 0.037, and OR = 0.80. 95% CI. 0.67 to 0.96, P = 0.019, respective ly). There was a 3.51-fold increase in the risk of calciphylaxis associated with each mg/dL increase in the mean serum phosphate during the year prior to diagnosis (95% CI. 0.99 to 12.5, P = 0.052). At the time of diagnosis o f calciphylaxis. for each 10 IU/L increment in alkaline phosphatase, the ri sk of calciphylaxis increased by 19% (OR = 1.19. 95% CI. 1.00 to 1.40, P = 0.045). Body mass index, diabetes. blood pressure, aluminum, and higher dos age of erythropoietin and iron dextran were not independent predictors of c alciphylaxis. Calciphylaxis independently increased the risk of death by ei ghtfold (OR = 8.58. 95% CI. 3.26 to 22.6. P < 0.001). Conclusions. Female gender, hyperphosphatemia. high alkaline phosphatase, a nd low serum albumin are risk factors For calciphylaxis. Calciphylaxis is a ssociated with a very high mortality.