Cumulative Load of Systolic BP May Better Predict CV Risk in T2D Patients vs Standard BP Measures
In patients with type 2 diabetes (T2D) cumulative load of systolic blood pressure (SBP) may better predict risk for major cardiovascular (CV) events compared with traditional measures of BP, according to study findings published in the Journal of the American College of Cardiology.
“An optimal measure as a risk factor for cardiovascular disease would account for both the magnitude and duration of elevated BP. Cumulative BP load, defined as the area under the curve expressed in units of mm Hg by time, is such a measure and has been associated with target organ damage,” wrote first author Nelson Wang, MD, clinical associate lecturer at Sydney Medical School, University of Sydney, and colleagues. “The only prior study of this measure was not only small and retrospective in nature, but also calculated cumulative BP load from ambulatory BP monitoring estimated over a short (24-hour) period.”
“An optimal measure as a risk factor for cardiovascular disease would account for both the magnitude and duration of elevated BP. Cumulative BP load, defined as the area under the curve expressed in units of mm Hg by time, is such a measure and has been associated with target organ damage.”
Using a post-hoc analysis of patients with T2D followed by the ADVANCE-ON (Action in Diabetes and Vascular Disease: Preterax and Diamicron-MR Controlled Evaluation) randomized clinical trial, Wang and colleagues evaluated the association between cumulative SBP load and risk for major CV events over 24 months and compared the predictive value for CV outcomes of the cumulative measure to that of systolic BP, time-below-target systolic BP and visit-to-visit systolic BP variability.
For the study, cumulative SBP load was defined as the area under curve for SBP values ≥130 mm Hg divided by the area under curve for all measured SBP values over a 24-month exposure period.
FINDINGS
The study’s cohort comprised 9338 patients with T2D who were included in the follow-up observational study after the conclusion of ADVANCE-ON. The mean age of participants at baseline was 65 years and 42% were women.
The median follow-up was 7.6 years during which investigators report there were 1469 major CV events, 1615 deaths (660 were CV-related), 491 myocardial infarctions, and 674 strokes.
Wang et al calculated that each 1-standard deviation increase in cumulative SBP load conferred a 14% increased risk for major CV events (HR = 1.14; 95% CI, 1.09-1.2), a 13% increased risk for all-cause mortality (HR = 1.13; 95% CI, 1.13-1.18) and a 21% increased risk for CV death (HR = 1.21; 95% CI, 1.13-1.29).
The study authors observed that increased cumulative SBP load was more likely among older participants and among those with more traditional CV risk factors.
In separate analyses, the research team found that the predictive value of SBP load for CV risk outperformed standard measures including mean SBP, time-below-target SBP, and visit-to-visit SBP variability in terms of Akaike information criterion (25 255) and net reclassification indexes (difference in C statistic, 0.0052; 95% CI, 0.0009-0.0095).
“Although the present study only assessed cumulative systolic BP load over 24 months, clinicians should recognize the importance of cumulative systolic BP load over a lifetime,” the researchers wrote. This long-horizon approach, they add, should emphasize early intervention including lifestyle change and pharmacologic therapy as needed.
Reference: Wang N, Harris K, Hamet P, et al. Cumulative systolic blood pressure load and cardiovascular risk in patients with diabetes. J Am Coll Cardiol. 2022;80:1147–1155. doi: 10.1016/j.jacc.2022.06.039
