Intensive blood pressure (BP) therapy is associated with a significantly lower risk for serious cardiovascular events in the adult population with diabetes in the United States, according to a recent study published in the Journal of the American College of Cardiology.
In this study, participant data from 2 large, nationally representative epidemiological surveillance studies, the Action to Control Cardiovascular Risk in Diabetes-Blood Pressure (ACCORD BP) trial (n=4507) and the National Health and Nutrition Examination Survey, (NHANES; n=1943; conducted between 2005 and 2014), were used and analyzed to estimate how the ACCORD BP study results could be generalized to populations with diabetes in the United States. Primary outcome measures were the first occurrence of nonfatal myocardial infarction, nonfatal stroke, or cardiovascular death. The data were analyzed statistically using weighted Cox proportional hazards regression models with robust standard errors.
Researchers used transportability methods to reweight individual participant data from the ACCORD BP trial to the NHANES trial population and to generalize the ACCORD BP population to the overall population for cardiovascular risk factors. Weighting was necessary because the ACCORD BP participants lacked racial/ethnic diversity, were more educated, differed clinically in terms of glycated hemoglobin (HbA1c) and fasting plasma glucose levels and duration of diabetes, and had greater cardiovascular risks than the general population. Weighting improved generalizability of the data based on ethnicity, lower HbA1c levels, fasting glucose levels, and other variables.
Compared with the unweighted results, the weighted results were favorable for intense BP treatment (hazard ratio [HR] 0.67; 95% CI, 0.49-0.91) and stroke outcomes (HR 0.33; 95% CI, 0.17-0.62). The transported results yielded, for the weighted sample, 14.4 total cardiovascular events in the intensive BP treatment arm vs 20.2 in the standard arm per 1,000 person-years (P= .03), which differed from the unweighted sample at 21.27 cardiovascular events per 1,000 person-years in the standard arm and 18.98 in the intensive arm.
Conversely, total mortality (HR 0.91; 95% CI, 0.62-1.32) and risk for microvascular events (HR 1.00; 95% CI, 0.75-1.33) did not differ between intensive and standard therapy groups. Serious adverse events more commonly occurred in the weighted intensive therapy group (incidence rate ratio 1.97; 95% CI, 1.09-3.58).
Researchers explained that, despite weighting, the data and findings were still limited among racial/ethnic minorities and populations with relatively lower cardiovascular risk.
Researchers conclude that their results should be cautiously interpreted and that additional studies are necessary to better inform BP treatment guidelines.
Berkowitz SA, Sussman JB, Jonas DE, Basu S. Generalizing intensive blood pressure treatment to adults with diabetes mellitus. J Am Coll Cardiol. 2018; 72(11):1214-1223.