Blood pressure and stroke risk among diabetic patients

Abstract

Context: Blood pressure (BP) control can reduce the risk of stroke among diabetic patients; however, it is not known whether the lowest risk of stroke is among diabetic patients with the lowest BP level.

Objective: Our objective was to investigate the race-specific association of different levels of BP with stroke risk among diabetic patients in the Louisiana State University Hospital-based longitudinal study.

Design, setting, and participants: We prospectively investigated the race-specific association of different levels of BP at baseline and during an average of 6.7 years of follow-up with incident stroke risk among 17,536 African American and 12,618 white diabetic patients within the Louisiana State University Hospital System.

Main outcome measure: We evaluated incident stroke until May 31, 2012.

Results: During follow-up, 2949 incident cases of stroke were identified. The multivariable-adjusted hazard ratios of stroke associated with different levels of systolic/diastolic BP at baseline (<110/65, 110-119/65-69, 120-129/70-80 [reference group], 130-139/80-90, 140-159/90-100, and ≥160/100 mm Hg) were 1.88 (95% confidence interval = 1.38-2.56), 1.05 (0.80-1.42), 1.00, 1.05 (0.86-1.27), 1.12 (0.94-1.34), and 1.47 (1.24-1.75) for African American diabetic patients and 1.42 (1.06-1.91), 1.22 (0.95-1.57), 1.00, 0.88 (0.72-1.06), 1.02 (0.86-1.21), and 1.28 (1.07-1.54) for white diabetic patients, respectively. A U-shaped association of isolated systolic or diastolic BP at baseline and during follow-up with stroke risk was observed among both African American and white diabetic patients. The U-shaped association was confirmed in both patients who were and were not taking antihypertensive drugs.

Conclusions: The current study suggests a U-shaped association between BP and the risk of stroke. Aggressive BP control (<110/65 mm Hg) and high BP (≥160/100 mm Hg) are associated with an increased risk of stroke among both African American and white patients with type 2 diabetes.

Figure 1.

HRs for incident stroke by systolic BP in African American (A) and white (C) and diastolic BP in African American (B) and white (D) subjects, adjusted for age, gender, BMI, LDL cholesterol, HbA1c, GFR, type of insurance, income, smoking, use of antihypertensive drugs, glucose-lowering agents, and cholesterol-lowering agents.