Incidence of graft-versus-host-disease in Germany – evidence from health care claims data

Abstract Introduction Graft-versus-host disease (GvHD) can occur as an immunological response after an allogeneic hematopoietic cell transplantation (allo-HCT). Due to the rarity of the disease German epidemiological data are scarce. Moreover, not all cases of GvHD are properly documented in daily practice. Against this background, this study aims at providing new estimates on the incidence of GvHD in Germany. Methods Based on a large German claims database, a retrospective longitudinal analysis was conducted over a six-year period. Patients were selected that received allo- HCT between 2014 and 2015. Follow up period was three years. To adjust the incidence for undocumented cases, steroid prescriptions after an allo-HCT was used as an approximation. Based on both documented and undocumented GvHD patients, incidence rates were calculated. Results Among 3,737,317 eligible database enrollees, we identified 297 patients who received an allo-HCT between 2014 and 2015. Depending on the extrapolation method, this corresponds to a yearly incidence of 2,760-3,246 in Germany. 134 of the 297 patients (i.e. 45.1%) developed a documented GvHD within three years after the transplantation which translates into a yearly incidence of 1,278–1,419 GvHD patients. Based on the medication regimens, we identified 83 additional patients with an suspected GvHD without a documented diagnosis. Extrapolated to the German population, our estimates suggests that the annual incidence of GvHD including undocumented cases could be as high as 2,069 − 2,298 which is higher than previously reported. Conclusion More patients may be affected by GvHD in Germany than reported. Appropriate adjustments need to be made when utilizing administrative data.