Background: Medication utilization and costs increased over the last decade, but the effects of race/ethnicity have never been well studied in longitudinal data. We analyzed reports of prescription medication use to (1) identify trajectories of use and (2) determine predictors associated with a large increase in use. Specifically, variations in medication use by race/ethnicity were examined.
Methods: We analyzed the Study of Women's Health Across the Nation cohort with a median of 14 years of follow-up. Group-based trajectory models helped distinguish women with a low use of medications versus those with heavy use. Logistic regression was used to estimate the odds ratio (OR) for each racial/ethnic group associated with heavy use, controlling for potential baseline confounders.
Results: The 2,798 women sampled had a mean age of 46 years at baseline and the median number of medications at baseline was 2, increasing to 4 over the follow-up period. Trajectory models identified that 16% of participants demonstrated heavy use of medications, from a median of 5 at baseline to 10 medications at final follow-up. Regression models controlling for age, obesity, number of comorbid conditions, and pain found that Hispanic (OR = 0.085, 95% confidence interval [CI]: 0.037-0.20), Chinese (OR = 0.32, 95% CI: 0.16-0.63), Japanese (OR = 0.33, 95% CI: 0.17-0.64), and Black (OR = 0.79, 95% CI: 0.57-1.11) women had lower odds for heavy use compared with White women.
Conclusions: Longitudinal medication use among women in Study of Women's Health Across the Nation (SWAN) differed by race/ethnicity with non-White women having a lower odds of heavy use.