The impact of multimorbidity on severe COVID-19 outcomes in community and congregate settings

Purpose

This study examined the impact of multimorbidity on severe COVID-19 outcomes in community and long-term care (LTC) settings, alone and in interaction with age and sex.

Methods

We conducted a retrospective cohort study of all Ontarians who tested positive for COVID-19 between January-2020 and May-2021 with follow-up until June 2021. We used cox regression to evaluate the adjusted impact of multimorbidity, individual characteristics, and interactions on time to hospitalization and death (any cause).

Results

24.5% of the cohort had 2 or more pre-existing conditions. Multimorbidity was associated with 28% to 170% shorter time to hospitalization and death, respectively. However, predictors of hospitalization and death differed for people living in community and LTC. In community, increasing multimorbidity and age predicted shortened time to hospitalization and death. In LTC, we found none of the predictors examined were associated with time to hospitalization, except for increasing age that predicted reduced time to death up to 40.6 times. Sex was a predictor across all settings and outcomes: among male the risk of hospitalization or death was higher shortly after infection (e.g. HR for males at 14 days = 30.3) while among female risk was higher for both outcome in the longer term (e.g. HR for males at 150 days = 0.16). Age and sex modified the impact of multimorbidity in the community.

Conclusion

Community-focused public health measures should be targeted and consider sociodemographic and clinical characteristics such as multimorbidity. In LTC settings, further research is needed to identify factors that may contribute to improved outcomes.

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.