Outcomes on peritoneal dialysis in patients with primary kidney disease related to multiple myeloma: A cohort study with data from the French Language Peritoneal Dialysis Registry

Background: Kidney impairment (KI) is a frequent complication of multiple myeloma (MM), with chronic kidney disease (CKD) often necessitating dialysis. Peritoneal dialysis (PD) offers quality-of-life advantages over haemodialysis (HD), yet its use in patients with CKD secondary to MM (CKD-MM) remains understudied. This study investigates the characteristics and outcomes of PD in CKD-MM patients compared to those with other kidney diseases. Methods: This retrospective observational study analysed data from the French Language PD Registry (RDPLF) for patients initiating PD between 2010 and 2020. A 4:1 ratio random sampling was drawn from patients with other kidney diseases to create a control group. Outcomes included death, transfer to HD and kidney transplantation. Cox regression models assessed the impact of CKD-MM on these outcomes, adjusting for baseline variables and treatment era. Results: Of 12,861 PD patients, 96 (<1%) had CKD-MM. These patients exhibited higher comorbidities and were less likely to be listed for kidney transplantation compared to controls. Among the 96 patients with CKD-MM, 51 (53%) died, 29 (30%) transferred to HD, and 5 (5%) underwent kidney transplant. CKD-MM was not associated with increased risks of death (cause-specific hazard ratio [cs-HR] 1.18, 95% CI 0.83-1.67) nor transfer to HD (cs-HR 0.73, 95% CI 0.45-1.18). However, CKD-MM patients had a significantly lower chance of transplantation (cs-HR 0.22, 95% CI 0.08-0.59). Conclusion: PD is a viable modality for CKD-MM, with outcomes comparable to other kidney diseases. Increased attention to PD initiation and transplant access may further optimise care for these patients.