Burden of multimorbidity and polypharmacy among cancer survivors: a population-based nested case–control study

Abstract

Purpose Individuals living with cancer have been shown to have a higher burden of comorbid disease and multimorbidity in comparison to their cancer-free counterparts consequently, leaving them at risk of polypharmacy (i.e., ≥ 5 medications) and its potential negative effects. The primary aim of the current study was to examine the self-reported prevalence of and association between multimorbidity and prescription medication use in a population-based sample of adult cancer survivors (CS). Methods This retrospective, nested case–control study drew participant data from the Atlantic Partnership for Tomorrow’s Health cohort. CS (n = 1708) were matched to 4 non-cancer controls (n = 6832) by age and sex. Prevalence of polypharmacy by number of chronic conditions and age was estimated with 95% CI. Logistic regression was used to examine the association between multimorbidity and polypharmacy while adjusting for sociodemographic and lifestyle factors. The comorbidity–polypharmacy score was also calculated as an estimate of disease burden. Results Multimorbidity was common in both CS (53%) and non-cancer controls (43%); however, a significantly higher percentage of CS reported multimorbidity (p < 0.001). Prescription medication use was also found to be significantly higher among CS (2.3 ± 2.6) compared to non-cancer controls (1.8 ± 2.3; p < 0.0001). Exploratory comorbidity–polypharmacy score analyses indicated that CS had a significantly higher overall disease burden than the age/sex-matched non-cancer controls. Conclusions As CS appear to be at a higher risk of multimorbidity and polypharmacy and by extension, increased healthcare burden, ongoing education on the prevention of medication-related harm, and interventions to reduce the occurrence of both co-morbid disease and unnecessary medications are warranted.