Yanchen Zhang, Kristin M Corapi, Maria Luongo, Ravi Thadhani, Sagar U Nigwekar

Calciphylaxis is a rare but devastating condition in end-stage renal disease (ESRD) patients. Most research in the field of calciphylaxis is focused on hemodialysis (HD) patients; however, data on calciphylaxis incidence, risk factors, and mortality in peritoneal dialysis (PD) patients are limited. In this cohort study, we examined data from adult patients who initiated PD for ESRD management at our institute's PD unit from January 2001 to December 2015. Associations with the development of calciphylaxis were examined for clinical, laboratory, and medication exposures. Incidence of calciphylaxis and mortality in PD patients who developed calciphylaxis were analyzed. Treatments administered to treat calciphylaxis in PD patients were summarized. In this cohort of 63 patients, 7 patients developed calciphylaxis (incidence rate: 9.0 per 1,000 patient-years). Median age of PD patients who developed calciphylaxis was 50 years, 57% were white, 71% females, and 71% were previously on HD. Female sex, obesity, HD as a prior dialysis modality, recurrent hypotension, elevated time-averaged serum phosphorous levels, reduced time-averaged serum albumin levels, and warfarin therapy were associated with increased calciphylaxis risk in univariate logistic regression analyses. Intravenous sodium thiosulfate was administered in 57% of PD patients who developed calciphylaxis. One-year mortality in PD patients who developed calciphylaxis was 71% despite multimodal treatment including sodium thiosulfate, hyperbaric oxygen, cinacalcet, and wound debridement. Calciphylaxis is a rare but frequently fatal condition in PD patients. Our study provides critical early insights into calciphylaxis incidence, risk factors, and prognosis in PD patients. Sample size and characteristics of patients included in our study limit generalizability to overall PD population and warrant examination in larger independent studies.