Risk Factors Influencing Outcomes of Atrial Fibrillation in ALLHAT.

Background And Aims: ALLHAT, a randomized, double-blind, active-controlled, multicenter clinical trial of high risk hypertensive participants, compared treatment with an ACE-inhibitor (lisinopril) or calcium channel blocker (amlodipine) with a diuretic (chlorthalidone). Primary outcome was the occurrence of fatal coronary heart disease or nonfatal myocardial infarction. For this report, post-hoc analyses were conducted to determine the contribution of baseline characteristics of participants with or without baseline or incident atrial fibrillation (AF) and atrial flutter (AFL) to stroke, heart failure (HF), coronary heart disease (CHD), and mortality outcomes.

Methods And Results: Minnesota Coding of baseline and biennial in-trial ECGs was used to determine the 334 baseline and 537 incident AF/AFL cases, respectively participants with AF/AFL: Cox regression was used to estimate hazard ratios of presence versus absence of either baseline or incident AF/AFL (as time-dependent covariate) for occurrence of stroke, CHD, HF, or mortality, while adjusting for selected baseline characteristics. Adjusted Cox regression was used to obtain hazard ratios (HRs) for presence versus absence of selected baseline characteristics among those with and without either baseline or incident AF/AFL. After adjusting for baseline characteristics, baseline AF/AFL was associated with stroke, HF, and mortality (HRs [95% CIs] 3.18, [2.34-4.33]; 2.65 [2.02-3.49]; and 2.10 [CI, 1.73-2.55], respectively, P < 0.05). Incident AF/AFL was a significant risk factor for HF and mortality (HRs 2.80 and 2.06, respectively, P < 0.05). Risk factor profiles for clinical outcomes for those with and without baseline or incident AF/AFL were largely similar.

Conclusions: AF/AFL is a significant risk factor for stroke, HF, and mortality. Additional risk factors for these outcomes were generally similar for participants with and without baseline or incident AF/AFL.