We examined the associations between blood pressure indices (SBP, DBP, mean arterial pressure and pulse pressure) and cardiovascular disease (CVD) mortality among persons with or without diabetes mellitus (NON-DM) in a multiethnic cohort.Methods:
We included 17 650 participants from National Health and Nutrition Examination Survey III and 1439 participants from Diabetes Heart Study (total n = 19 089, 16.3% had diabetes mellitus, mean age 48.5 years, 44.4% white, 27.1% black, 28.5% other race, 54.4% women). Cox proportional hazard, cubic spline and area under the curve analyses were used to assess the associations. CVD death was ascertained via social security registry or the National Death Index.Results:
After a mean (SD) of 16.2 (6.1) years of follow-up, 17.9% of diabetes mellitus and 8.8% of those NON-DM died of CVD. Diabetes mellitus was associated with an increased risk of CVD death [hazard ratio (95% confidence interval): 1.50 (1.25–1.82)]. One SD increase in SBP was significantly associated with CVD mortality in NON-DM [1.28 (1.18–1.39)] but not diabetes mellitus [1.04 (0.88–1.23)] in the full Cox models. Adjusted cubic spline analysis showed significant nonlinear but different association between SBP and CVD mortality among diabetes mellitus (U-shaped) and NON-DM (J-shaped). The C-statistics of our full model in NON-DM and diabetes mellitus were (0.888 vs. 0.735, P < 0.001). SBP showed a trend toward improving C statistics in NON-DM but not diabetes mellitus.Conclusion:
The association between SBP and CVD mortality risk is nonlinear but different in diabetes mellitus (U-shaped) and NON-DM (J-shaped), explaining why aggressive blood pressure lowering may have different outcomes in these two groups.