Abstract
Background: The objective of this study is to assess the impact of immune checkpoint inhibitors (ICIs) and multimorbidity on healthcare expenditures among older patients with late-stage melanoma. Materials & methods: A retrospective longitudinal cohort study using Surveillance, Epidemiology and End Results linked with Medicare claims was conducted. Generalized linear mixed models were used to analyze adjusted relationships of ICI, multimorbidity and ICI-multimorbidity interaction on average healthcare expenditures. Results: Patients who received ICI and those who had multimorbidity had significantly higher average total healthcare expenditures compared with ICI nonusers and no multimorbidity. In the fully adjusted model using ICI-multimorbidity interaction, no excess cost was added by multimorbidity. Conclusion: Use of ICIs, regardless of multimorbidity, is associated with increased healthcare expenditures.