Blood pressure control with amlodipine add-on therapy in patients with hypertension and diabetes: results of the Amlodipine Diabetic Hypertension Efficacy Response Evaluation Trial.

ABSTRACT

BACKGROUND: Attainment of blood pressure (BP) goals in patients with diabetes is critical both to reduce the risk of cardiovascular events and to delay the progression of renal disease. While therapeutic guidelines advise initial therapy with an angiotensin-converting enzyme inhibitor or angiotensin receptor blocker, monotherapy with these agents may not be sufficient to attain target BP. OBJECTIVE: The ADHT (Amlodipine Diabetic Hypertension Efficacy Response Evaluation Trial) evaluated the efficacy and safety of adding amlodipine to the treatment regimen of patients with hypertension and diabetes who were already receiving either quinapril or losartan as monotherapy. METHODS: ADHT was a double-blind, double-dummy, 22-week trial conducted in the US. After a washout period of 7-13 days, patients (aged 30-75 y) with hypertension and diabetes were randomized to receive quinapril 20 mg/day plus placebo or losartan 50 mg/day plus placebo for 4 weeks, titrated to 40 mg or 100 mg (if required), respectively, for an additional 4 weeks to achieve their BP goals (<130/80 mm Hg). At week 8, either amlodipine 5 mg/day or placebo was added for an additional 12 weeks, with titration to 10 mg at week 14 if the BP goal was not achieved. RESULTS: Efficacy of add-on therapy was evaluated in 411 patients (amlodipine 211, placebo 200). BP goal was reached by 27.5% of patients when amlodipine was added to quinapril or losartan monotherapy, compared with 12.5% when placebo was added (OR 2.73; 95% CI 1.61 to 4.64; p < 0.001). When added to quinapril or losartan monotherapy, amlodipine reduced BP by 8.1/5.4 mm Hg, compared with a 1.6/0.7 mm Hg decrease with add-on placebo (p < 0.001). Amlodipine, quinapril, and losartan were well tolerated. CONCLUSIONS: Amlodipine is safe and effective when added to quinapril or losartan monotherapy to help lower BP toward therapeutic targets in patients with hypertension and diabetes.