Geriatric conditions, rather than multimorbidity, as predictors of disability and mortality among octogenarians: A population-based cohort study.

Aim: To examine the impact of geriatric conditions and multimorbidity on the risk of incident disability and mortality among young-old and old-old adults.

Methods: The present study used nationally-representative data from the "Survey of Health and Living Status of the Elderly in Taiwan" for the years 2003 and 2007. Non-disabled older adults were divided into two age groups (65-79 years and ≥80 years). Chronic morbidities and geriatric conditions were assessed in 2003. Incident disability was defined as dependency in one or more activities of daily living in 2007. Vital statistics of the participants was linked to death registration data through 31 December 2007. Multivariable logistic regression and Cox regression were used to determine the effect of multimorbidity and geriatric conditions on health outcomes.

Results: Among those aged 65-79 years (n = 1874), the presentation of multimorbidity or two or more geriatric conditions was related to incident disability. Among octogenarians, the presentation of one or more geriatric conditions, but not multimorbidity, was shown to be independently associated with the risk of disability. Multimorbidity was related to a higher adjusted risk of mortality in the young-old group (hazard ratio 1.54; 95% confidence interval 1.1-2.2) but not in the old-old group. Among octogenarians, those with two or more geriatric conditions had a higher adjusted risk of mortality (hazard ratio 1.7; 95% confidence interval 1.2-2.5), compared with those with 0-1 geriatric conditions.

Conclusions: The risk of incident disability and mortality increased in octogenarians with geriatric conditions, but not in cases with multimorbidity.