This study aimed to understand the changes and correlation in the long-term trends of polypharmacy and the utilization of health care services in a population over the age of 50 years through the use of a national database. A total of 2813 subjects who participated in surveys in 1999, 2003, and 2007 were selected as the samples. Each subject was followed-up for the period of 9 years. From 1999 to 2007, the proportion of mild and severe polypharmacy cases increased from 41.5% (1999) to 51.3% (2003) and 57.1% (2007), respectively. This study found that the more severe the polypharmacy was, the higher the risk of health care service utilization would be. The Generalized Estimating Equation model of multivariate analysis showed that the incidence rate ratio of medical utilization increased with the severity of polypharmacy, as did the use of advanced medical resources (ie, the number of hospitalizations). In particular, the increase in incidence rate ratio was more significant in 3 aspects: (1) number of pharmacy visits; (2) number of emergency room admissions; and (3) number of hospitalizations. The government should establish policies and guidance for the safe use of medicines to ensure reduced risk for older people.
Keywords: elderly; generalized estimating equation (GEE); health care services; panel survey of cohort study; polypharmacy.