Moderate-severe grade of chronic graft versus host disease and younger age (less than 45 years old) are risk factors for avascular necrosis in adult patients undergoing allogeneic hematopoietic cell transplantation.

Avascular necrosis (AVN) is a debilitating complication of allogeneic hematopoietic cell transplantation (HCT). A retrospective review of 845 patients who underwent HCT was conducted. Cumulative incidence of AVN was 6.3% at 4 years. The following risk factors were significantly associated with AVN risk on univariate analysis: age < 45 (p=0.004), moderate to severe chronic GvHD (p<0.001), reduced intensity conditioning (p=0.02), and a diagnosis of acute leukemia (p=0.045). Multivariate analysis confirmed two risk factors: younger age (<45 years), 9.0% vs 4.4% (p=0.011, hazard ratio (HR) 2.134), and moderate-severe chronic GvHD, 15.4% vs 2.1% (p<0.001, HR 4.950). A risk score model was generated assigning a score to each risk factor. A score of 1 was assigned to moderate-severe GvHD or those with age <45. Total score was calculated, thus dividing patient into three groups: low (score 0, n=349, 41.3%), intermediate (score 1, n=379, 44.9%), and high risk (score 2; n=116, 13.7%). This risk score could stratify the patients according to AVN risk (p<0.001). The risk of AVN was 1.5% in the low risk, 6.2% in the intermediate risk, and 20.8% in the high risk groups. Moderate-severe chronic GvHD and younger age (<45 years) are key risk factors for AVN following allogeneic HCT.