Calciphylaxis diagnosis, management and future directions: a comprehensive update on behalf of the European Renal Association CKD-MBD Working Group

Calciphylaxis, or calcific uraemic arteriolopathy, is a rare and life-threatening condition predominantly affecting people receiving dialysis. Characterized by painful necrotic skin lesions due to arteriolar calcification and thrombosis, calciphylaxis is associated with high morbidity and mortality. Diagnosis is frequently delayed due to misdiagnosis and an absence of specific diagnostic tests. Current treatment approaches are largely based on registry data and small uncontrolled studies. This update brings together the latest understanding of calciphylaxis pathogenesis, diagnostic approaches and management, highlighting recent advances and future directions. Pathophysiological mechanisms include vascular smooth muscle cell osteogenic transformation, loss of endogenous calcification inhibitors (fetuin-A, matrix Gla protein, pyrophosphate), systemic inflammation and thrombosis. The potential prognostic role of biomarkers, including the calciprotein particle crystallization test (T50) and plasma pyrophosphate, are also discussed. Management remains complex, with no proven treatments. A multifaceted, and multi-professional team approach is fundamental. Sodium thiosulfate remains widely used despite the lack of trial evidence. Recent investigational therapies, including SNF472 and INZ-701, target key calcification pathways and offer promise. The Better Evidence and Translation for Calciphylaxis (BEAT-Calci) adaptive platform trial represents a landmark step in evaluating multiple therapies systematically. National registries remain vital for informing prevalence estimates and improving real-world outcome data. Looking ahead, future research should prioritize the development and validation of diagnostic criteria, and prognostic tools integrating clinical risk factors with biomarkers. In addition, we propose the routine inclusion of patient-reported experience measures in calciphylaxis studies to better capture treatment impact in this vulnerable population.