Mortality among patients with diffuse large B-cell lymphoma and mental disorders: a population-based study

Background: Mental disorders have been reported in patients with diffuse large B-cell lymphoma (DLBCL), but studies examining their association with mortality are lacking.

Methods: We conducted a population-based study using linked administrative health-care databases from Ontario, Canada. All patients with DLBCL 18 years of age or older treated with rituximab-based therapy between January 1, 2005, and December 31, 2017, were identified and followed until March 1, 2020. Mental disorders were defined as either preexisting or postdiagnosis (after lymphoma treatment initiation). Cox proportional hazards models were used to estimate the adjusted hazard ratio (HR) between mental disorders and 1-year and all-cause mortality while controlling for covariates.

Results: We identified 10 299 patients with DLBCL. The median age of the cohort was 67 years; 46% of patients were female, and 28% had a preexisting mental disorder. At 1-year follow-up, 892 (9%) had a postdiagnosis mental disorder, and a total of 2008 (20%) patients died. Preexisting mental disorders were not associated with 1-year mortality (adjusted HR = 1.06, 95% confidence interval [CI] = 0.96 to 1.17, P = .25), but postdiagnosis disorders were (adjusted HR = 1.51, 95% CI = 1.26 to 1.82, P = .0001). During a median follow-up of 5.2 years, 2111 (22%) patients had a postdiagnosis mental disorder, and 4084 (40%) patients died. Both preexisting and postdiagnosis mental disorders were associated with worse all-cause mortality (preexisting adjusted HR = 1.12, 95% CI = 1.04 to 1.20, P = .0024; postdiagnosis adjusted HR = 1.63, 95% CI = 1.49 to 1.79, P < .0001).

Conclusions: Patients with DLBCL and mental disorders had worse short-term and long-term mortality, particularly those with postdiagnosis mental disorders. Further studies are needed to examine mental health service utilization and factors mediating the relationship between mental disorders and inferior mortality.