Differential effects of nifedipine and co-amilozide on the progression of early carotid wall changes

Background-Common carotid artery intima-media thickness (IMT) progression w as compared between 4 years of treatment with nifedipine and diuretic. Methods and Results-This study, ancillary to the International Nifedipine G ITS Study: Intervention as a Goal in Hypertension Treatment (INSIGHT), invo lved nifedipine 30 mg or co-amilozide (hydrochlorothiazide 25 mg and amilor ide 2.5 mg) with optional subsequent titration. Among 439 randomized hypert ensive patients, 324 had greater than or equal to1 year of follow-up (inten t-to-treat group), and 242 completed follow-up (until-end-of-study group). Ultrasonography was performed at baseline, 4 months later, and then every y ear. Central computerized reading provided far-wall IMT, diameter, and cros s-sectional area IMT (CSA-IMT). The primary outcome was IMT progression rat e (slope of IMT-time regression). Secondary outcomes were changes from base line (Delta) in IMT, diameter, and CSA-IMT. In the until-end-of-study popul ation, between-treatment differences existed in IMT progression rate (P=0.0 02), Delta IMT (P=0.001), and Delta CSA-IMT (P=0.006), because IMT progress ed on co-amilozide but not on nifedipine. In the intent-to-treat population , treatment differences existed in Delta IMT (P=0.004) and Delta CSA-IMT (P =0.04) but not in IMT progression rate (P=0.09). Patients with greater than or equal to2, 3, or 4 years of follow-up showed treatment differences in I MT progression rate (P=0.04, 0.004, 0.007, respectively), Delta IMT (P=0.00 5, 0.001, 0.005), and Delta CSA-IMT (P=0.025, 0.013, 0.015). Diameter decre ased more on co-amilozide than on nifedipine in the intent-to-treat populat ion (P<0.05), whereas blood pressure decreased similarly on both treatments . Conclusions-A difference in early carotid wall changes is shown between 2 e qually effective antihypertensive treatments.