Characteristics and long-term follow-up of participants with peripheral arterial disease during ALLHAT.

BACKGROUND

Hypertension is a major risk factor for peripheral artery disease (PAD). Little is known about relative efficacy of antihypertensive treatments for preventing PAD.

OBJECTIVES

To compare, by randomized treatment groups, hospitalized or revascularized PAD rates and subsequent morbidity and mortality among participants in the Antihypertensive and Lipid-Lower Treatment to Prevent Heart Attack Trial (ALLHAT).

DESIGN

Randomized, double-blind, active-control trial in high-risk hypertensive participants.

PARTICIPANTS

Eight hundred thirty participants with specified secondary outcome of lower extremity PAD events during the randomized phase of ALLHAT.

INTERVENTIONS/EVENTS: In-trial PAD events were reported during ALLHAT (1994-2002). Post-trial mortality data through 2006 were obtained from administrative databases. Mean follow-up was 8.8 years.

MAIN MEASURES

Baseline characteristics and intermediate outcomes in three treatment groups, using the Kaplan-Meier method to calculate cumulative event rates and post-PAD mortality rates, Cox proportional hazards regression model for hazard ratios and 95 % confidence intervals, and multivariate Cox regression models to examine risk differences among treatment groups.

KEY RESULTS

Following adjustment for baseline characteristics, neither participants assigned to the calcium-channel antagonist amlodipine nor to the ACE-inhibitor lisinopril showed a difference in risk of clinically advanced PAD compared with those in the chlorthalidone arm (HR, 0.86; 95 % CI, 0.72-1.03 and HR, 0.98; 95 % CI, 0.83-1.17, respectively). Of the 830 participants with in-trial PAD events, 63 % died compared to 34 % of those without PAD; there were no significant treatment group differences for subsequent nonfatal myocardial infarction, coronary revascularizations, strokes, heart failure, or mortality.

CONCLUSIONS

Neither amlodipine nor lisinopril showed superiority over chlorthalidone in reducing clinically advanced PAD risk. These findings reinforce the compelling need for comparative outcome trials examining treatment of PAD in high-risk hypertensive patients. Once PAD develops, cardiovascular event and mortality risk is high, regardless of type of antihypertensive treatment.