Combined Therapy with Peritoneal Dialysis and Hemodialysis in Japan: Current Status and Criteria for Initiation and Discontinuation

Abstract Background Combined therapy with peritoneal dialysis (PD) and hemodialysis (HD) is widely used in Japan for patients with inadequate dialysis and/or who develop fluid overload during PD. However, current patterns of practice and criteria for initiating or discontinuing combined therapy remain inadequately defined. We investigated the contemporary status of combined therapy and the criteria used in clinical practice in Japan. Methods This study consisted of two parts. In Study 1, we analyzed data on patients receiving combined therapy extracted from the Japanese Society for Dialysis Therapy Renal Data Registry via the Web-based Analysis of Dialysis Data Archives system. In Study 2, we conducted a nationwide questionnaire survey of PD facilities registered with the Japanese Society for Peritoneal Dialysis to evaluate current practice patterns and physician criteria for transfer from PD to combined therapy and from combined therapy to HD alone. Results Study 1 identified 1,963 patients receiving combined therapy (age, 62 ± 12 years; 71.9% male). Approximately 90% were asymptomatic or had mildly symptomatic performance status. HD and hemodiafiltration (HDF) were used in 62.5% and 34.1% of patients, respectively, and 89.2% received HD/HDF once weekly. In Study 2, responses were obtained from 210 of 314 facilities (67%). Among the 616 patients included in the survey, 548 (89.0%) had transferred from PD to combined therapy and were included in subsequent analyses. The main reasons for transfer were fluid overload (43.6%), inadequate dialysis (26.7%), or both (23.9%). Frequently used indicators for treatment decisions include Kt/V, β2-microglobulin, uremic symptoms, fluid overload-related symptoms, and natriuretic peptides. Common threshold values were a total weekly Kt/V of 1.7 and a β2-microglobulin level of 30 mg/L. For discontinuation of combined therapy to prevent encapsulating peritoneal sclerosis (EPS), frequently used indicators included PD duration, PD-related peritonitis, and peritoneal deterioration, with frequently used thresholds of 10 years, three peritonitis episodes, and a high peritoneal equilibration test category. Conclusions In Japan, combined therapy is primarily introduced to manage inadequate dialysis and fluid overload while preserving PD, and objective measures such as Kt/V and β2-microglobulin are widely used. Evidence-based guidance for initiation and discontinuation, particularly criteria for preventing EPS, is needed.