Chronic disease, functional status, and self-ascribed causes of disabilities among noninstitutionalized older people in Spain.

BACKGROUND: A major component of disability is related to chronic disease, but the study of self-reported causes of disability could add new aspects in understanding this process. The main objective of this work was to determine the associations between chronic diseases and disability and to describe the pattern of self-reported causes of the disabilities present in older persons.

METHODS: We carried out a survey in a probabilistic sample of people aged 65 and older of the city of Madrid. The initial sample size was 1001. Subjects were interviewed in their homes. We asked about the presence of 14 chronic conditions. Self-reported difficulty and dependence in 9 noninstrumental activities of daily living (ADLs) were ascertained. Subjects were asked to report the main cause responsible for the disability. Multivariate logistic regression models were constructed to estimate the association of each chronic condition with the probability of having disability.

RESULTS: Final sample size was 772 people (overall response rate 77.0%). Interviews answered by proxies were 7.5%. Only 4.5% declared no chronic condition. Osteoarthitis/rheumatism was the most prevalent condition (56.8%). In addition, 63.2% were independent, 21.3% were independent with difficulty (in at least one ADL), and 15.5% were dependent (in at least one ADL). Subjects attributed to osteoarthitis and to aging 41.8% and 17.1% of all disabilities, respectively. Chronic conditions strongly associated with disability were cerebrovascular disease (adjusted odds ratio [OR]: 3.51 [95% confidence interval: 1.44-8.60]), depression/anxiety disorders (OR: 2.72 [1.83-4.05]), and diabetes (OR: 2.18 [1.24-3.83]).

CONCLUSIONS: Cerebrovascular diseases, depression/anxiety disorders, and diabetes were the conditions more clearly related to disability. On the other hand, a large proportion of subjects attribute their disabilities to osteoarthritis and old age.