Peak exercise SBP below predicted value tied to increased CVD, mortality risk

A peak systolic blood pressure (SBP) at clinical exercise testing that is slightly lower than the predicted value appears predictive of future cardiovascular disease (CVD) and mortality, suggests a study. Higher peak SBP, however, is not associated with such risks.

“Using age and sex-specific reference values in interpreting the SBP response to exercise might facilitate interpretation in exercise testing and improve adverse event prediction in clinical practice,” the researchers said.

The study obtained data from 10,096 clinical exercise tests (54 percent men, age 18‒85 years), which were cross-linked with outcome data from national registries. The researchers then compared peak SBP with recently published reference percentiles along with percentage predicted peak SBP using reference equations. Finally, they used natural cubic spline modelling and Cox regression to analyse data stratified by sex and baseline cardiovascular risk profile.

Median follow-up times were 7.9 years for all-cause mortality and 5.6 years for incident CVD. Compared with individuals within the 10th to 90th percentile, those with peak SBP below the 10th percentile had adjusted all-cause mortality risk of 2.00 (95 percent confidence interval [CI], 1.59‒2.52) in men and 2.60 (95 percent CI, 1.97‒3.44) in women. The risk for incident CVD was 1.55 (95 percent CI, 1.28‒1.89) and 1.34 (95 percent CI, 1.05‒1.71), respectively. [J Hypertens 2022;40:300-309]

The adjusted risks of all-cause death and incident CVD for men in the upper 90th percentile were 0.35 (95 percent CI, 0.22‒0.54) and 0.72 (95 percent CI, 0.57‒0.92), respectively, compared with those within the 10th to 90th percentile; such risks were not statistically significant in women.

In spline modelling, a continuous increase in risk was observed with peak SBP values <100 percent of predicted in both men and women, with no increase in risk >100 percent of predicted.

Previous studies have established that exercise-induced hypotension, often defined as either a drop in SBP below the resting value or after an initial increase, is a robust negative predictor of all-cause and cardiovascular mortality. [Atherosclerosis 2014;237:13-22; Prog Cardiovasc Dis 2008;51:135-160]

“Our results extend this, and we show that in reference to predicted peak SBP, there was an increased risk of both all-cause mortality and CVD incidence already at a peak SBP corresponding to 90 percent of predicted,” the researchers said. “This persisted after additional adjustment for baseline cardiovascular risk factors and comorbidities.”

On the other hand, the risk associated with reaching a high peak SBP has been contentious. Exercise SBP is physiologically linked to exercise workload, via cardiac output, so individuals reaching high workloads are expected to achieve higher peak SBP. Therefore, considering workload in interpreting SBP response has become essential, according to the researchers. [Sports Med 2018;48:1763-1771; Eur J Prev Cardiol 2020;27:978-987]

“Part of the previous controversy in the literature on whether a high peak SBP is associated with worse prognosis, could lie in the fact that studies linking a high peak SBP to worse outcome were performed in older individuals and/or with a lack of adjustment for age, while studies linking a high peak SBP to future hypertension often were undertaken in a middle-age population,” they added. [Adv Med Sci 2017;62:317-329]