Association between blood pressure and risk of cardiovascular hospital admissions among people with type 2 diabetes

OBJECTIVE: To investigate the association between systolic and diastolic blood pressure (BP) and risk of hospitalisation among patients with type 2 diabetes. METHODS: 4704 patients with type 2 diabetes from 18 general practices in Cambridgeshire were included. BP was assessed in 2008-2009. The primary outcome was cardiovascular hospital admissions in 2009-2011. Adjusted relative risks for each BP measurement group were estimated using Cox models. Further dose-response relationships between BP and risks were explored using restricted cubic spline models. RESULTS: Over a median follow-up of 2 years, we recorded 5322 hospital admissions. There was a non-linear relationship between systolic (SBP) and diastolic (DBP) BP and the risk of cardiovascular hospitalisation (both p<0.001 for linearity test). The BP associated with the lowest risk of cardiovascular hospitalisation was 137 (95% CI 133 to 141)/78 (95% CI 76 to 80) mm Hg. The discrimination of the model could be significantly improved with either an SBP threshold or a DBP threshold (both p<0.0001). CONCLUSIONS: Among patients with type 2 diabetes, the risk of cardiovascular hospitalisation is lowest with a BP of 133-141/76-80 mm Hg. This concurs with the latest recommended randomised controlled trial based BP target of 140/80 from the American Diabetes Association.