Synergistic interaction between alcoholism and polypharmacy on the risk of falls in the elderly

The aim of this study was to explore the interaction between alcoholism and polypharmacy on the risk of falls in the elderly in Taiwan. A data set of 1 million randomly sampled National Health Insurance claims in Taiwan was used in our analysis, from which 3482 new cases of falls in 2000-2008 and 13928 randomly selected controls without falls, both aged ≥ 65 years, were identified for a case-control study. Polypharmacy was defined as the average daily use of five or more prescribed drugs. Relative risks were estimated by adjusted odds ratio (OR) and 95% confidence interval (CI) using a multivariate logistic regression analysis.In comparison with participants using one or no drugs without alcoholism, the OR increased from 1.15 (95% CI 1.01-1.32) for those using two to four drugs without alcoholism, to 1.27 (95% CI 1.10-1.47) for those using five or more drugs without alcoholism, up to 5.32 (95% CI 1.58-18.0) for those using two to four drugs with alcoholism, and as high as to 6.29 (95% CI 2.22-17.8) for those using five or more drugs with alcoholism. We conclude that polypharmacy may interact with alcoholism and further increases the risk of falls in the elderly.