Chronic condition clusters and functional impairment in older cancer survivors: a population-based study

Kelly M. Kenzik, Erin E. Kent, Michelle Y. Martin, Smita Bhatia, Maria Pisu

The purpose of the study is to identify chronic condition clusters at pre- and post-cancer diagnosis, evaluate predictors of developing clusters post-cancer, and examine the impact on functional impairment among older cancer survivors. We identified 5991 survivors age 65 and older of prostate, breast, colorectal, lung, bladder, kidney, head and neck, and gynecologic cancer and non-Hodgkin lymphoma from the Surveillance, Epidemiology and End Results-Medicare Health Outcomes Survey resource. Survivors completed surveys pre- and post-cancer diagnosis on 13 chronic conditions and functional status. Among those with ≥2 conditions, exploratory factor analysis identified clusters of conditions. Differences in cluster frequency from pre- to post-cancer diagnosis were evaluated across the top five cancer types using chi-square tests. Modified Poisson regression models estimated the relative risk of developing clusters post-diagnosis. Chi-square tests evaluated associations between function and clusters. Clusters included the following: cardiovascular disease cluster (pre 6.1 % and post 7.7 %), musculoskeletal cluster (28.2 % and 29.3 %), metabolic cluster (14.9 % and 17.6 %), and the major depressive disorder risk (MDDr) + gastrointestinal (GI) + pulmonary condition cluster (5.8 % and 8.7 %). Increases in MDDr + GI + Pulmonary cluster from pre- to post-cancer diagnosis were observed for prostate, lung, and colorectal cancer survivors. Functional impairment was more prevalent in survivors with defined clusters, especially in MDDr + GI + pulmonary, compared to survivors with ≥2 un-clustered conditions. Distinct condition clusters of two or more chronic conditions are prevalent among older cancer survivors. Cluster prevalence increases from pre- to post-cancer diagnosis and these clusters have a significant impact on functional limitations. Tailored management on specific multimorbidity patterns will have implications for functional outcomes among older survivors.