Health status and mental distress in people with cancer and comorbid conditions: The Australian National Health Survey analysis.

INTRODUCTION Data on the impact of specific comorbidities on health outcomes is limited. We compared health status and mental distress between individuals with and without cancer according to comorbidity type. METHODS A cross-sectional analysis using data from the Australian National Health Survey 2017-18 including all respondents aged ≥25 years with and without a history of cancer. The odds of poor health and mental distress were reported according to cancer status, and specific individual and cluster of comorbidities. RESULTS There were 1982 individuals (52% female) with cancer and 12,635 (51% female) without cancer. Individuals with cancer were older, and more likely to have a comorbidity compared with those without cancer. They were more likely to report poor health than those without cancer for each specific comorbidity; except for skin conditions and infectious diseases; with the adjusted odds ratio (aOR) ranging from 1.34 (95% CI = 1.01-1.79) for digestive disorders to 2.93 (95% CI = 1.62-5.29) for blood conditions. The strongest association with poor health (aOR 2.79, 95% CI = 2.27-3.43) and mental distress (aOR 9.01, 95% CI = 7.25-11.20) was observed for those with a comorbid mental illness. Exploratory cluster analysis identified four distinct comorbidity clusters: low comorbidity, musculoskeletal, respiratory and cardiometabolic; cancer survivors in the cardiometabolic cluster had a higher odds of reporting poor health (aOR 3.50, 95% CI = 2.48-4.92) and mental distress (aOR 2.33, 95% CI = 1.53-3.55) than those with a low comorbidity. CONCLUSIONS Comorbidities in cancer survivors were common and associated with inferior health status, although the magnitude of the effect varied by comorbidity type. Risk assessment and management of comorbidities should be an important priority for cancer care and research.