Blood pressure and stroke risk among diabetic patients.

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.