Longitudinal Patterns of Blood Pressure, Incident Cardiovascular Events, and All-Cause Mortality in Normotensive Diabetic People

Abstract

Lower blood pressure (BP) within the normotensive range has been suggested to be deleterious in diabetic people using antihypertensive drugs. We hypothesized that BP <120/80 mm Hg and BP trajectories may predict further risk of all-cause mortality or cardiovascular events in normotensive diabetic individuals. We included 3159 diabetic adults, free of hypertension, atherosclerotic cardiovascular diseases, or cancer in 2006 (baseline), from a community-based cohort including 101 510 participants. A total of 831 participants with BP <120/80 mm Hg and 2328 participants with BP of 120 to 139/80 to 89 mm Hg were included. BP and other clinical covariates were repeatedly measured every 2 years. During 7 years of follow-up, we documented 247 deaths and 177 cardiovascular events. Diabetic people with BP <120/80 mm Hg had a 46% increased risk of all-cause mortality (95% confidence interval, 10%–93%) compared with those with BP of 120 to 139/80 to 89 mm Hg at baseline. We then estimated the association between BP trajectories from 2006 to 2008 and adverse events among 2311 diabetic people who had both BP measures at 2006 and 2008. Relative to stable BP of 120 to 139/80 to 89 mm Hg, having persistently BP <120/80 mm Hg (hazard ratio: 2.35; 95% confidence interval, 1.10–5.01) or a spontaneous decrease in BP from 120 to 139/80 to 89 to <120/80 mm Hg (hazard ratio: 3.04; 95% confidence interval, 1.56–5.92) was significantly associated with an increased risk of all-cause mortality during 2008 to 2014. A rise in BP from 120 to 139/80 to 89 to ≥140/90 mm Hg conferred a high risk of cardiovascular events (hazard ratio: 1.98; 95% confidence interval, 1.24–3.17). In normotensive diabetic people having a low BP or a decline in BP was both associated with an increased risk of all-cause mortality, whereas development of incident hypertension increased the risk of cardiovascular events.