Use of chronic medications among a large, commercially-insured US population

Purpose. To examine use of chronic therapies by females and males of all ages. Methods. Participants were 1 295 948 members of a large US pharmacy benefit manager. The use of chronic medications by males and females during 1999 was examined overall and within 16 commonly-used chronic drug groups. Dependent variables were use of a drug group, number of drug groups used, number of prescriptions filled and sum of costs, both within each drug group and overall. Combination therapy was defined as using at least two of the 16 chronic therapy groups during 1999. Results. Females were more likely than males to use chronic medications during the study year (36.5 vs. 22.4%, p < 0.001). Generally, the likelihood of using a chronic medication increased with age for both sexes. Commonly-used chronic medications accounted for 54 and 50% of prescriptions for females and males respectively, and for 53% of total drug costs for both sexes. There were few meaningful sex differences in the likelihood of using particular drug groups. Of those who took chronic drugs 14% used combination chronic therapy. Conclusions. This study provides demographic information regarding treatment of chronic conditions that can be used to aid policy decisions and to provide an impetus for future research.