Validated clinical risk score for acute graft-versus-host disease in adult allogeneic hematopoietic cell transplantation

Acute graft-versus-host disease (aGVHD) contributes to significant morbidity after allogeneic hematopoietic cell transplantation (allo-HCT). We aimed to develop and validate a clinical score to identify patients with significantly different risk for developing aGVHD. Analysis included adults who underwent allo-HCT during 2008-2019. Eligibility criteria were widely inclusive of transplant indications, donor types, graft types, conditioning regimens, and GVHD prophylaxis regimens. The final cohort of 21 796 patients was randomly split into training and validation cohorts, with 15 258 (70%) and 6538 (30%) patients, respectively. The primary outcome was grade 2 to 4 aGVHD, and the secondary outcome was grade 3 to 4 aGVHD, by day 100 posttransplant. Risk scores were developed using the training cohort, tested using the validation cohort, and stratified into 4 percentile groups. The odds of grade 2 to 4 aGVHD by day 100 posttransplant were 1.50 (95% confidence interval [CI], 1.29-1.75; P< .0001) for the 25th to 50th percentile group, 2.0 (95% CI, 1.78-2.40; P< .0001) for the 50th to 75th percentile group, and 3.1 (95% CI, 2.72-3.65; P< .0001) for the >75th percentile group compared with the ≤25th percentile group in the validation cohort. The odds of grade 3 to 4 aGVHD by day 100 posttransplant were 1.4 (95% CI, 1.11-1.74; P = .0043) in the 25th to 50th percentile group, 2.0 (95% CI, 1.61-2.49; P< .0001) in the 50th to 75th percentile group, and 3.2 (95% CI, 2.64-3.98; P< .0001) in the >75th percentile group compared with the ≤25th percentile group in the validation cohort. Here, to our knowledge, we have developed the first validated, widely inclusive clinical risk score for the development of aGVHD after allo-HCT.