Long-term mental health service utilization among patients with diffuse large B-cell lymphoma: a population-based study.

Mental health disorders are common in diffuse large B-cell lymphoma (DLBCL), yet long-term mental health service utilization (MHU) remains poorly characterized. We evaluated MHU rates and associated sociodemographic factors in patients undergoing curative treatment. This population-based retrospective matched-cohort study used Ontario administrative data; patients treated with rituximab-based chemotherapy (2005-2017) were matched 1:4 (age/sex) to non-cancer controls and followed up to 15 years. Difference-in-differences Poisson regression compared MHU between groups, adjusting for sociodemographic variables. Among 10,132 patients and 40,528 controls, DLBCL patients had significantly higher adjusted MHU at 5 years: outpatient visits (aRR 1.22), emergency visits (aRR 1.75), and hospitalizations (aRR 1.97). Elevated rates persisted at 10 and 15 years. Higher MHU was associated with younger age, female sex, lower income, and urban residence. DLBCL patients demonstrated persistently elevated MHU for up to 15 years post-treatment, underscoring the need for mental health integration into survivorship care.