Volume 51 | Number 4 | August 2016

Abstract List

Chi‐Chen Chen Ph.D., Shou‐Hsia Cheng Ph.D.


To examine the effects of potentially inappropriate medication () use on health care outcomes in elderly individuals using an instrumental variable () approach.

Data Sources/Study Setting

Representative claim data from the universal health insurance program in Taiwan from 2007 to 2010.

Study Design

We employed a panel study design to examine the relationship between and hospitalization. We applied both the naive generalized estimating equation () model, which controlled for the observed patient and hospital characteristics, and the two‐stage residual inclusion (2) model, which further accounted for the unobserved confounding factors. The prescription rate of the physician most frequently visited by each patient was used as the .

Principal Findings

The naive models indicated that patient use was associated with a higher likelihood of hospitalization (odds ratio [], 1.399; 95 percent confidence interval [], 1.363–1.435). Using the physician prescribing rate as an , we identified a stronger significant association between and hospitalization (, 1.990; 95 percent , 1.647–2.403).


use is associated with increased hospitalization in elderly individuals. Adjusting for unobserved confounders is needed to obtain unbiased estimates of the relationship between and health care outcomes.