Rising burden of multimorbidity and related socio-demographic factors: a repeated cross-sectional study of Ontarians

OBJECTIVE: This study aimed to provide population-level data regarding trends in multimorbidity over 13 years. METHODS: We linked provincial health administrative data in Ontario, Canada, to create 3 cross-sectional panels of residents of any age in 2003, 2009, and 2016 to describe: (i) 13-year trends in multimorbidity prevalence and constellations among residents and across age, sex, and income; and (ii) chronic condition clusters. Multimorbidity was defined as having at least any 2 of 18 selected conditions, and further grouped into levels of 2, 3, 4, or 5 or more conditions. Age-sex standardized multimorbidity prevalence was estimated using the 2009 population as the standard. Clustering was defined using the observed combinations of conditions within levels of multimorbidity. RESULTS: Standardized prevalence of multimorbidity increased over time (26.5%, 28.8%, and 30.0% across sequential panels), across sex, age, and area-based income. Females, older adults and those living in lower income areas exhibited higher rates in all years. However, multimorbidity increased relatively more among males, younger adults, and those with 4 or 5 or more conditions. We observed numerous and increasing diversity in disease clusters, namely at higher levels of multimorbidity. CONCLUSION: Our study provides relevant and needed population-based information on the growing burden of multimorbidity, and related socio-demographic risk factors. Multimorbidity is markedly increasing among younger age cohorts. Also, there is an increasing complexity and lack of common clustering patterns at higher multimorbidity levels. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.17269/s41997-021-00474-y.