Late infectious complications in hematopoietic cell transplantation survivors: a population-based study

Few studies have compared the incidence of infections occurring ≥2 years after hematopoietic cell transplant (HCT) with other cancer patients and the general population. In this study, ≥2-year HCT survivors who were Washington residents treated from 1992 through 2009 (n = 1792; median age, 46 years; 52% allogeneic; 90% hematologic malignancies) were matched to individuals from the state cancer registry (n = 5455, non-HCT) and driver's license files (n = 16 340; Department of Licensing [DOL]). Based on hospital and death registry codes, incidence rate ratios (IRRs; 95% confidence interval [CI]) of infections by organism type and organ system were estimated using Poisson regression. With 7-year median follow-up, the incidence rate (per 1000 person-years) of all infections was 65.4 for HCT survivors vs 39.6 for the non-HCT group (IRR, 1.6; 95% CI, 1.3-1.9) and 7.2 for DOL (IRR, 10.0; 95% CI, 8.3-12.1). Bacterial and fungal infections were each 70% more common in HCT vs non-HCT cancer survivors (IRR, 1.7; P < .01), whereas the risk for viral infection was lower (IRR, 1.4; P = .07). Among potentially vaccine-preventable organisms, the IRR was 3.0 (95% CI, 2.1-4.3) vs the non-HCT group. Although the incidences of all infections decreased with time, the relative risk in almost all categories remained significantly increased in ≥5-year HCT survivors vs other groups. Risk factors for late infection included history of relapse and for some infections, history of chronic graft-versus-host disease. Providers caring for HCT survivors should maintain vigilance for infections and ensure adherence to antimicrobial prophylaxis and vaccination guidelines.