Blood pressure and cardiovascular outcomes in patients with diabetes and high cardiovascular risk

Abstract

Aims: Optimal blood pressure for prevention of cardiovascular (CV) events in patients with Type 2 diabetes mellitus (T2DM) remains uncertain and there is concern for increased risk with low diastolic blood pressure (DBP). This study analysed the association between blood pressure and CV outcomes in high-risk patients with T2DM. Methods and results: Patients with T2DM and elevated CV risk were enrolled in the Saxagliptin Assessment of Vascular Outcomes Recorded in patients with diabetes mellitus-Thrombolysis in Myocardial Infarction 53 trial. Cardiovascular outcomes were compared in the biomarker subgroup (n = 12 175) after stratification by baseline systolic blood pressure (SBP) and DBP. Adjusted risk was calculated by blood pressure stratum using clinical covariates plus N-terminal pro-B-type natriuretic peptide (NT-proBNP) and high-sensitivity troponin-T (hsTnT). Trends were tested using linear and quadratic models. Adjusted risk of the composite endpoint of CV death, myocardial infarction (MI), or ischaemic stroke showed U-shaped relationships with baseline SBP and DBP (Pquadratic ≤ 0.01) with nadirs at SBP 130-140 or DBP 80-90 mmHg. Diastolic blood pressure <60 mmHg was associated with increased risk of MI (adjusted hazard ratio 2.30; 95% confidence interval 1.50-3.53) relative to DBP 80-90 mmHg. Adjusted odds of hsTnT concentration ≥14 ng/L showed U-shaped relationships with SBP and DBP (Pquadratic ≤ 0.01). The relationships between low DBP, elevated hsTnT, and increased MI remained after exclusion of patients with prior heart failure or NT-proBNP >median, suggesting that the relationship was not due to confounding from diagnosed or undiagnosed heart failure. Conclusions: In patients with diabetes and elevated CV risk, even after extensive adjustment for underlying disease burden, there was a persistent association for low DBP with subclinical myocardial injury and risk of MI.