Adherence with multiple-combination antihypertensive pharmacotherapies in a US managed care database

The aim of this analysis was to assess the impact of multiple combination therapies on medication possession ratios (MPRs) in an antihypertensive naive population.

Data were collected using the Integrated Healthcare Information Solution's National Benchmark Database (January 1997 to June 2004). Data from patients who received 2-pill pharmacotherapy with valsartan or valsartan/hydrochlorothiazide (HCTZ) in a fixed-dose combination (FDC) + amlodipine were compared with those from patients who received 3-pill therapy with valsartan + HCTZ + amlodipine as 3 free-drug components. MPR was calculated by dividing the total days' supply for the lower value in the case of individual drug components, or the number of days' supply in the case of FDC, by 365 (the number of days during the 1-year study period the medication regimen was prescribed). A general linear regression was then performed to determine the effect of treatment group on MPR, controlling for the demographic and clinical characteristics.

Data from 908 patients were included (527 women, 381 men; mean age, 53.9 years; 2-pill treatment with valsartan + amlodipine, 224 patients; 2-pill treatment with valsartan/HCTZ + amlodipine, 619; and 3-pill therapy with valsartan + HCTZ + amlodipine, 65). The MPR values were 75.4%, 73.1%, and 60.5%, respectively (P = 0.005). MPR improved with age (69.6% in the subset aged 18-<36 years vs 75.2% in the subset aged >or=64 years; P = 0.023).

In these antihypertensive-naive patients with hypertension, MPR decreased with the increase in tablets per regimen, and improved MPR was correlated with increasing age. These findings suggest patient compliance improves with simplified pharmacotherapeutic approaches.