Abstract
With the increasing prevalence of comorbidity in an ageing population, it is crucial to better understand the impact of comorbidity on health-related quality of life (HRQoL) after lymphoma or multiple myeloma (MM) diagnosis. We included 261 newly diagnosed patients (67% response rate) diagnosed with lymphoma or MM between October 2020 and March 2023 in a longitudinal survey. The European Organisation for Research and Treatment of Cancer (EORTC) questionnaires were used to measure generic and disease-specific HRQoL. Evidence-based guidelines for interpretation of the EORTC questionnaires were used to identify clinical importance. Patients were classified as having 'no comorbidity', 'mild comorbidity' (e.g. arthrosis or rheumatism), or 'moderate-severe comorbidity' (e.g. heart or lung disease), using the adapted self-administered comorbidity questionnaire. At diagnosis, the mean age was 64 years, 63% were male and 38% reported no comorbidity, 33% mild comorbidity, and 29% moderate-severe comorbidity. Patients with mild or moderate-severe comorbidity reported clinically relevant worse HRQoL at diagnosis than patients without comorbidity. One year post-diagnosis most outcomes showed clinically relevant improvement, irrespective of comorbidity. However, outcomes of physical functioning (β=-7.9, p < 0.05), global health status (β=-7.6, p < 0.05), bone pain (β = 8.1 to 9.1, p < 0.05), muscle/joint pain (β = 14.5 to 18.8, p < 0.01) and muscle weakness (β = 10.4 to 15.6, p < 0.05) improved less among those with comorbidity, and clinically relevant differences between comorbidity groups persisted over time. With clinically relevant worse HRQoL at diagnosis and less recovery of HRQoL during the first year after diagnosis in patients with comorbidity, consideration of both prognosis and HRQoL is important when making treatment decisions.