Multimorbidity,disability, and mortality in community-dwelling older adults

Objective

To describe factors associated with multimorbidity in community-dwelling older adults; to determine if a simple measure of multimorbidity predicts death over 5 years; and to assess if any effect of multimorbidity on mortality is independent of key covariates.

Design

Analysis of an existing population-based cohort study. Cox proportional hazards models were constructed for time to death.

Setting

Manitoba.

Participants

A total of 1751 community-dwelling adults aged 65 and older were interviewed and followed for 5 years.

Main outcome measures

Age, sex, marital status, living arrangement, education, Mini-Mental State Examination (MMSE) score, Center for Epidemiologic Studies Depression Scale score, and the Older Americans Resource and Services Multidimensional Functional Assessment Questionnaire score were recorded for each participant. Multimorbidity was defined based on a simple list of common health complaints and diseases, followed by an open-ended question about other problems. These were summed and the scores ranged from 0 to 16. Death and time of death were determined during the 5-year interval by death certificate, administrative data, or proxy report.

Results

Multimorbidity was more prevalent in women; older age groups; and those with lower educational levels, lower MMSE scores, more depressive symptoms, and higher levels of disability. Multimorbidity was a predictor of mortality in unadjusted models (hazard ratio 1.09, 95% CI 1.05 to 1.12). In models adjusting for age, sex, education, marital status, living arrangement, and Center for Epidemiologic Studies Depression Scale and MMSE scores, this effect persisted (hazard ratio 1.04, 95% CI 1.00 to 1.08). However, after adjusting for functional status, the effect of multimorbidity was no longer significant.

Conclusion

Multimorbidity predicts 5-year mortality but the effect might be mediated by disability.