Late infections after high‐dose therapy and autologous stem cell transplantation for lymphoma: A Danish population‐based study

Infectious complications after high-dose therapy and autologous stem cell transplantation (HDT-ASCT) for lymphoma are the leading cause of late non-relapse mortality. Characterizing the risk of infectious complications over time is important for rational follow-up and because alternatives to HDT-ASCT exist for some patients. This national cohort study investigated the risk of severe (defined by requiring hospitalization) late infections after 90 days among HDT-ASCT-treated patients with lymphoma in remission relative to the Danish background population (comparators) matched on age, sex and comorbidity score. Anti-cancer treatment after HDT-ASCT and death were competing events. This study included 781 patients and 3905 comparators. With a median follow-up of 7.7 years for patients, the incidence rate ratios of severe infections from 90 days until 2 years after HDT-ASCT was 8.43 (95% confidence interval (CI): 6.98-10.16) and the 2-year cumulative risk was 23.7% (95% CI: 20.7%-26.7%) for patients and 3.4% (95% CI: 2.9%-4.0%) for comparators. The risk of severe infections remained increased for up to 10 years after HDT-ASCT. Respiratory tract infections were the most frequent type, with a 2-year cumulative risk difference of 10.9% (95% CI: 8.6%-13.3%). Patients were more likely to be prescribed anti-infectives, including broad-spectrum antibiotics 5-10 years after HDT-ASCT.