Purpose: To estimate how much the presence of hypertension adds to the annual per capita and total medication expenditure among US adults.
Method: The study sample included 21,782 civilian non-institutionalized persons aged 18 years and older from the 2007 Medical Expenditure Panel Survey. Hypertension was defined as having a diagnosis of high blood pressure (excluding pregnancy) or taking blood pressure medications. We used a two-part model to examine all-cause medication expenditure associated with hypertension. A Logit model was used to predict the probability of incurring any medication expenditure. Then, a Generalized Linear Model was used to predict the amount of medication expenditure for those who incurred any. The estimated partial effects were averaged over the distribution to achieve a population-averaged interpretation.
Result: Hypertension prevalence was 32%. Overall, 67.9% of adults were taking prescribed medications; the proportion was higher among hypertensive (93.2%) compared to normotensive adults (55.7%) (P<.001). After controlling for demographic and socioeconomic characteristics, hypertensive adults were more likely to have medication expenditures than normotensive adults (OR: 6.42; P<.001). Among hypertensive adults, those 45 years and older were more likely to incur medication expenditure than those 18-44 years (45-64 years OR=3.00, P<.001; and ≥65 years OR=5.95, P<.001). Women were more likely than men to have medication spending (OR=2.91, P<.001). Hispanics were less likely than non-Hispanic whites to have medication spending (OR=0.51, P<.001). Medication costs increased significantly among hypertensive adults. Among adults taking medications, the average cost was $1,510 higher among hypertensive adults ($2,337) compared to normotensive adults ($827). Women had a larger cost difference between hypertensive and normotensive adults ($1, 652) than men ($1,336). The medication costs among hypertensive adults increased for each successive age group, $1,045 for those aged 18 – 44 years, $2,136 for those aged 45 – 64 years, and to $2,720 for those 65 years or older. The per capita difference in medication expenditures between hypertensive ($2,166) and normotensive ($464) adults increased after including their probabilities of incurring medication spending. Medication expenditure would be $68 billion lower if hypertensive patients did not have hypertension.
Conclusion: The presence of hypertension increased the all-cause medication expenditure substantially. Further research on cost-effective interventions is needed to reduce the prevalence of hypertension and increase control of hypertension among adults.