Polypharmacy among disabled Taiwanese elderly: a longitudinal observational study.

BACKGROUND AND OBJECTIVE

It is not known whether the correlates of polypharmacy among disabled elderly are similar to those for older adults in general. Furthermore, data on polypharmacy in the Taiwanese population are limited. Therefore, this study was conducted to determine the prevalence and correlates of polypharmacy among disabled Taiwanese elderly (aged >or=65 years).

METHODS

This was a longitudinal observational study conducted on information obtained between July 2001 and June 2002. Study participants consisted of nationally representative samples of 11,788 disabled Taiwanese elderly from the ANLTCNT (Assessment of National Long-Term Care Need in Taiwan) study. Polypharmacy and major polypharmacy were defined as prescription of >or=5 and >or=10 medications, respectively, on the day of maximum numbers of prescriptions of the study year. Subject characteristics were derived from the ANLTCNT study survey data. Healthcare-related characteristics, including medication prescriptions, were obtained from the National Health Insurance (NHI) claims data. Multivariate logistic regression was performed for statistical analysis.

RESULTS

One-fifth (21.5%) of the sample were aged >or=85 years, and 58% were female. The prevalence of polypharmacy and major polypharmacy among disabled Taiwanese elderly was 81% and 38%, respectively. Nearly one-third (32.5%) of disabled Taiwanese elderly were exposed to polypharmacy for >or=181 days in 1 year. Compared with those with a low tendency for visiting multiple providers, those with intermediate tendency (odds ratio [OR] 3.61; 95% CI 3.11, 4.18) and those with high tendency (OR 10.24; 95% CI 8.56, 12.24) were more likely to be exposed to polypharmacy. Other significant correlates of polypharmacy in the multivariate logistic regression model included age <85 years, living in urban areas, higher number of chronic conditions, poorer physical functioning, preference for visiting independent clinics and not being institutionalized.

CONCLUSION

The prevalence of polypharmacy was extremely high among disabled Taiwanese elderly. Visiting multiple healthcare providers was one of the strongest correlates. Policies that encourage the disabled elderly to establish primary care relationships and that promote geriatric care models may decrease the prevalence of polypharmacy and associated adverse outcomes in this group.