Objective: To assess compliance with antihypertensive therapy and healthcare utilization among African American and White Medicaid recipients who are receiving fixed-dose combination amlodipine besylate/benazepril HCl or a dihydropyridine calcium channel blocker plus an angiotensin-converting enzyme inhibitor prescribed as separate agents (free-combination).
Design: Longitudinal, retrospective, cohort analysis of South Carolina Medicaid claims for the years 1997 through 2002. Followup was 12 months from the index date, defined as the first prescription dispensing date for a study drug.
Setting and participants: South Carolina Medicaid beneficiaries receiving fixed-dose (n=3363) and free-combination (n=713) therapy, including 3016 African Americans and 1060 White patients.
Main outcome measures: Compliance was defined as the total days' supply of drug (excluding last prescription fill) divided by the length of followup; healthcare utilization included cost and number of claims associated with ambulatory services, hospital care, and prescription drugs.
Results: The cohort (N=4076) was 74.0% African American; mean age was 62.2 years. Compliance was significantly greater in patients who received fixed-dose therapy than in those who received free-combination therapy (58.6% vs 48.1%; P<.05). The average total cost of care was lower for the fixed-dose group ($4605) than for the free-combination group ($8531). African Americans and Whites were equally likely to receive the fixed-dose combination. However, compliance was lower among African American patients than among White patients (55% vs 61% respectively; P<.05). Costs and claims for ambulatory and hospital services were higher for African American patients, whereas drug costs and claims were higher for White patients.
Conclusion: Fixed-dose amlodipine besylate/benazepril HCl was associated with higher compliance rates than was free-combination therapy, independent of race. Lower compliance rates among African American patients may have contributed to the higher healthcare resource use and costs observed. Efforts to enhance medication compliance tailored to African Americans may improve outcomes and reduce costs in this high-risk population.