Reweighting simulation may reconcile SPRINT, ACCORD BP findings
medwireNews: Research suggests that giving patients with type 2 diabetes intensive blood pressure treatment as per the ACCORD BP study would be beneficial in a real-world US population.
The study involved using data from 1943 patients in the nationally representative NHANES population in a technique similar to propensity-score matching, to reweight the 4507 participants of ACCORD BP.
Among other changes, this technique increased the proportion of Hispanic people, those with a less than high-school education, and of never smokers, and lowered average levels of blood pressure, glycated hemoglobin, and triglycerides.
Prior to weighting, the ACCORD BP participants randomly assigned to receive intensive treatment had 18.98 cardiovascular events per 1000 person–years versus 21.27 per 1000 person–years among those in the standard treatment group, giving a nonsignificant 12% benefit. The corresponding rates after weighting were 14.4 versus 20.2 per 1000 person–years, giving a significant 33% difference.
“The estimated benefit of intensive treatment seen after reweighting is in line with those observed in the SPRINT trial, which helps harmonize the results of the 2 studies,” Seth Berkowitz (University of North Carolina at Chapel Hill School of Medicine, USA) and study co-authors write in the Journal of the American College of Cardiology.
They say that their findings support intensive blood pressure treatment in people with type 2 diabetes, but also highlight the paucity of evidence to guide treatment in “large segments” of the US population, “particularly racial/ethnic minorities and those with lower cardiovascular risk.”
However, rates of mortality, stroke, and microvascular outcomes were no different between groups ever after weighting, and the absolute rate of adverse events remained significantly increased in the intensive treatment group, at 7.04 versus 3.41 per 1000 person–years.
In a linked editorial, George Bakris and Tamar Polonsky (both from University of Chicago Medicine, Illinois, USA) observe that the major trials and meta-analyses to date have offered conflicting evidence as to the relative benefits of blood pressure treatment in people with and without diabetes, and the optimal targets.
But they say these “seemingly contradictory” findings “are not when one considers differences in the pathophysiology of hypertension in patients with diabetes,” noting the “accelerated vascular aging” in this subgroup.
“Adults with advanced microvascular disease and endothelial dysfunction from diabetes may therefore be more likely to experience adverse effects from aggressive [blood pressure] lowering, such as ischemia or hypotension,” say the editorialists.
“Thus, it is important to consider the entire spectrum of patients with diabetes, as well as their age, rather than placing everyone in the same matrix.”
They stress in particular that most participants of cardiovascular outcome studies are older than 60 years, whereas many real-world patients are younger, and conclude that “the rationale used to defend lower [blood pressure] targets should be based on risk and not be an absolute number.”
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