Time-adjusted direct medical costs of moderate-to-severe chronic graft-versus-host disease: a retrospective two-center cost analysis in Turkiye

Abstract

Introduction: Chronic graft-versus-host disease (cGVHD) imposes a substantial economic burden after allogeneic hematopoietic cell transplantation, yet evidence on cost determinants is limited, particularly from middle-income countries. The determinants of the daily intensity of direct medical costs in moderate-to-severe cGVHD were examined. Methods: Fifty patients treated between 2018 and 2023 at two private transplant centers in Turkiye were analysed retrospectively. Because treatment durations varied, cost was modeled as an intensity per day of observation using a Gamma generalized linear model with a log link and a log-time offset and robust (HC1) standard errors. Cost components and mortality were examined as exploratory analyses. Results: The mean total direct cost was 52,979 USD (SD 47,697), comprising medication (75.7%), inpatient (23.1%), and outpatient (1.3%) costs. Daily cost intensity was higher in male patients (cost ratio 2.163, 95% CI 1.451-3.224; +116% per day) and lower with older age (cost ratio 0.970 per year; -3.0% per year). Disease severity, transplant type, and organ involvement showed no association with daily cost intensity (joint Wald p > 0.5), indicating that severe disease raised cumulative cost mainly by extending treatment duration rather than the cost per day. Exploratory component-wise models suggested that medication intensity tracked disease characteristics whereas inpatient intensity tracked demographic factors. Mortality was 22% and underpowered. Discussion: Daily cost intensity was determined chiefly by male sex and younger age, whereas severity acted on cumulative cost through longer treatment. These hypothesis-generating findings support time-adjusted cost analysis in cGVHD.