Long-Term Variability of Blood Pressure, Cardiovascular Outcomes, and Mortality: The Look AHEAD Study

Abstract

Background: We evaluated the associations of visit-to-visit blood pressure (BP) variability with incident cardiovascular disease (CVD) and deaths in adults with type 2 diabetes.

Methods: We analyzed 4,152 participants in Look AHEAD (Action for Health in Diabetes) free of CVD events and deaths during the first 36 months of follow-up. Variability of systolic BP (SBP) and diastolic BP (DBP) across 4 annual visits was assessed using the intraindividual SD, variation independent of the mean, and coefficient of variation. Cox regression was used to generate the adjusted hazard ratios (aHRs) and 95% confidence intervals (CIs) for CVD (myocardial infarction [MI], stroke, or CVD-related deaths) and mortality.

Results: Over a median of 6.6 years, there were 220 MIs, 105 stroke cases, 62 CVD-related deaths, and 236 deaths. After adjustment for confounders including average BP, the aHRs for the highest (vs. lowest) tertile of SD of SBP were 1.98 (95% CI 1.01-3.92), 1.25 (95% CI 0.90-1.72), 1.26 (95% CI 0.96-1.64), 1.05 (95% CI 0.75-1.46), and 1.64 (95% CI 0.99-2.72) for CVD mortality, all-cause mortality, CVD, MI, and stroke, respectively. The equivalent aHRs for SD of DBP were 1.84 (95% CI 0.98-3.48), 1.43 (95% CI 1.03-1.98), 1.19 (95% CI 0.91-1.56), 1.14 (95% CI 0.82-1.58), and 0.97 (95% CI 0.58-1.60), respectively.

Conclusions: In a large sample of individuals with type 2 diabetes, a greater variability in SBP was associated with higher cardiovascular mortality and CVD events; a higher variability in DBP was linked to increased overall and cardiovascular mortality.

Keywords: blood pressure; blood pressure variability; cardiovascular diseases; diabetes; hypertension; mortality.