Evidence is currently equivocal on the added benefits of dual blockade of the renin-angiotensin-aldosterone system with the combination of either an ACE inhibitor (ACEI) plus an angiotensin II type 1 receptor antagonist (angiotensin receptor blocker [ARB]) or aliskiren, the first-in-class direct renin inhibitor, plus an ARB.
To compare the compliance, persistence, healthcare resource utilization, and healthcare costs associated with aliskiren plus ARB versus ACEI plus ARB combination therapies among adult patients diagnosed with hypertension.
Patients (aged ≥18 years) initiated on either combination therapy were identified in the Market-Scan Commercial and Medicare Supplemental Databases (1 July 2007 to 30 June 2008). The ARB components considered were candesartan, irbesartan, losartan, olmesartan, telmisartan, and valsartan. The ACEI components included benazepril, captopril, enalapril, fosinopril, lisinopril, moexipril, perindopril, quinapril, ramipril, and trandolapril. Outcomes measured during the 6-month study period included the proportion of days covered (PDC), treatment discontinuation, healthcare resource utilization, and changes in healthcare costs (study period minus 6-month baseline values). Risk-adjusted differences in outcomes between treatments and associated 95% confidence intervals (CIs) were estimated using multivariate regression models, controlling for demographics, region, co-morbidities, prescription drug use, and resource utilization during the baseline period.
Adjusting for baseline characteristics, aliskiren plus ARB patients (n= 1395) demonstrated a significantly higher PDC (67.0% vs 54.3%; difference 12.7%; 95% CI 10.6, 14.7) and a significantly lower discontinuation rate (50.4% vs 68.6%; odds ratio 0.46; 95% CI 0.40, 0.54) than ACEI plus ARB patients (n=16 507). Aliskiren plus ARB patients had significantly fewer all-cause hospitalizations (adjusted incidence rate ratio [IRR] 0.73; 95% CI 0.61,0.86) and significantly fewer all-cause emergency room (ER) visits (adjusted IRR 0.72; 95% CI 0.61, 0.85) than ACEI plus ARB patients. Compared with ACEI plus ARB therapy, aliskiren plus ARB therapy was associated with significantly larger increases in prescription costs by $US264 post therapy initiation (95% CI 153, 375), but with non-significantly greater reductions in total healthcare costs by -$583 (95% CI −2409, 1242) [2008 values].
In adult hypertensive patients, treatment with aliskiren plus ARB was associated with significantly better compliance/persistence and fewer hospitalizations and ER visits compared with ACEI plus ARB therapy. Reductions in total healthcare costs were non-significantly different between patients treated with aliskiren plus ARB versus ACEI plus ARB, despite the increased prescription costs associated with aliskiren plus ARB therapy.