Association Between Hypercoagulable Conditions and Calciphylaxis in Patients With Renal Disease: A Case-Control Study

IMPORTANCE: Calciphylaxis is a rare skin disease with high morbidity and mortality that frequently affects patients with renal disease. Hypercoagulable conditions are frequently observed in both patients with calciphylaxis and those with chronic kidney disease (CKD), complicating our understanding of which hypercoagulable conditions are specific to calciphylaxis. OBJECTIVE: To identify hypercoagulable conditions that are risk factors for developing calciphylaxis while controlling for CKD. DESIGN, SETTING, AND PARTICIPANTS: This was a case-control study, comparing the hypercoagulability status of patients with calciphylaxis and with renal disease with that of a matched control population at 2 large urban academic hospitals in Boston, Massachusetts. Retrospective medical record review of laboratory values was performed to identify patients with hypercoagulable conditions. Case and control patients were further stratified based on both severity of CKD and warfarin. Patients with a dermatologic diagnosis of calciphylaxis between 2006 and 2014 and concomitant CKD were included as cases (n = 38). Three controls (n = 114) per case patient with CKD were included, and were matched by age, sex, and race. MAIN OUTCOMES AND MEASURES: The rate of various hypercoagulable states (ie, antithrombin III [ATIII] deficiency, protein C and S deficiency, factor V Leiden mutation, prothrombin gene mutation [G20210A], elevated factor VIII level, lupus anticoagulant, anti-IgG or IgM cardiolipin antibodies, heparin-induced thrombocytopenia antibodies, and elevation of homocysteine) in patients with calciphylaxis compared with their matched controls. RESULTS: Of the calciphylaxis cohort, 28 (58%) were female and 18 (55%) were non-Hispanic white. Among all patients, lupus anticoagulant (13 [48%] positive in cases vs 1 [5%] in controls; P = .001), protein C deficiency (9 [50%] vs 1 [8%]; P = .02), and combined thrombophilias (18 [62%] vs 10 [31%]; P = .02) were found to be significantly associated with calciphylaxis. In a subanalysis of patients with stage 5 CKD, only lupus anticoagulant (12 [53%] vs 9 [0%]; P = .01) and combined thrombophilia (15 [63%] vs 1 [8%]; P = .004) remained significantly associated with calciphylaxis. In a separate subanalysis of warfarin-unexposed patients, only lupus anticoagulant (7 [50%] vs 1 [6%]; P = .01) and protein C deficiency (5 [46%] vs 10 [0%]; P = .04) remained significantly associated with calciphylaxis. CONCLUSIONS AND RELEVANCE: Presence of lu