Real-world survey of hematopoietic stem cell transplantation in Japan using a nationwide administrative claims database.

According to data from the Japanese registry managed by the Transplant Registry Unified Management Program, the number of autologous stem cell transplantations (auto-SCT) in 2018 was approximately 60% of that of allogeneic SCT (allo-SCT). The opposite trend has been reported in the United States. Thus, we hypothesized that auto-SCT is underreported in the registry. We analyzed anonymized aggregated data from the Diagnosis Procedure Combination (DPC) database, a nationwide administrative claims database in Japan. Counts for fiscal years (FY) 2017 and 2018 were obtained for autologous collections, auto-SCT, and allo-SCT by graft source, and summarized by key demographic and clinical characteristics, including disease category and in-hospital outcomes. In FY2018, the DPC data recorded 23 autologous bone marrow transplantations (BMT), 2,590 autologous peripheral blood stem cell transplantations (PBSCT), 1,238 allogeneic BMT, 1,072 allogeneic PBSCT, and 1,353 cord blood transplantations (CBT). Similar findings were observed in FY2017. We identified plasma cell neoplasms (48%) and lymphoma (43%) as the primary indications for autologous PBSCT. Compared with the Japanese transplant registry, allogeneic SCT counts were similar across graft sources, whereas autologous PBSCT counts were approximately 500 higher. However, due to differences in aggregation rules, these findings should be interpreted as approximate rather than precise estimates. Our analysis of nationwide claims-based DPC data indicates potential underreporting of autologous PBSCT in the Japanese registry. Our findings support the complementary use of DPC data with registry data to characterize real-world hematopoietic cell transplantation practice in Japan.