Workload-indexed blood pressure response is superior to peak systolic blood pressure in predicting all-cause mortality

Abstract

Aims The association between peak systolic blood pressure (SBP) during exercise testing and outcome remains controversial, possibly due to the confounding effect of external workload (metabolic equivalents of task (METs)) on peak SBP as well as on survival. Indexing the increase in SBP to the increase in workload (SBP/MET-slope) could provide a more clinically relevant measure of the SBP response to exercise. We aimed to characterize the SBP/MET-slope in a large cohort referred for clinical exercise testing and to determine its relation to all-cause mortality. Methods and results Survival status for male Veterans who underwent a maximal treadmill exercise test between the years 1987 and 2007 were retrieved in 2018. We defined a subgroup of non-smoking 10-year survivors with fewer risk factors as a lower-risk reference group. Survival analyses for all-cause mortality were performed using Kaplan–Meier curves and Cox proportional hazard ratios (HRs (95% confidence interval)) adjusted for baseline age, test year, cardiovascular risk factors, medications and comorbidities. A total of 7542 subjects were followed over 18.4 (interquartile range 16.3) years. In lower-risk subjects ( n = 709), the median (95th percentile) of the SBP/MET-slope was 4.9 (10.0) mmHg/MET. Lower peak SBP (<210 mmHg) and higher SBP/MET-slope (>10 mmHg/MET) were both associated with 20% higher mortality (adjusted HRs 1.20 (1.08–1.32) and 1.20 (1.10–1.31), respectively). In subjects with high fitness, a SBP/MET-slope > 6.2 mmHg/MET was associated with a 27% higher risk of mortality (adjusted HR 1.27 (1.12–1.45)). Conclusion In contrast to peak SBP, having a higher SBP/MET-slope was associated with increased risk of mortality. This simple, novel metric can be considered in clinical exercise testing reports.

Age- and gender-specific upper limits and reference equations for workload-indexed systolic blood pressure response during bicycle ergometry

“…In addition, recent data suggest that using workloadindexed SBP response to exercise is superior to peak SBP in predicting mortality. 21 Earlier studies have found either increased 1,2,4 or decreased 7-9 risk of cardiovascular disease or death with higher peak SBP, in different populations. This can possibly be explained by the confounding effect of maximum workload (exercise capacity), associated both with higher SBP (via greater cardiac output) 12,14,15 and with better survival.…”

“…The workload-indexed SBP response to exercise has been proposed as a more physiologically relevant metric than peak SBP, 11 and current guidelines on hypertension management 10 as well as exercise testing recommendations 16,17 highlight the importance of considering workload when interpreting SBP during exercise. However, while reference values on peak SBP are available, [18][19][20] normative data for the workloadindexed SBP response to exercise testing are scarce 21 and, to our knowledge, non-existing for females and for bicycle ergometry. Thus, the current results fill an important gap in the literature and may aid physicians and exercise physiologists in interpretation of the SBP response during clinical bicycle exercise testing.…”

“…[18][19][20] This may be of importance as recent data suggest that a steeper increase in SBP in relation to workload is a stronger prognostic factor of mortality than peak SBP alone. 21 However, the lack of normative data on the workload-indexed SBP response to exercise in the literature currently limits its applicability in clinical practice and research settings.…”

Risk prediction with blood pressure during physical activity: A METter of exercise?

“…The authors concluded that this may be related to a better distinction in identifying Korotkoff sounds in higher (systolic) BPs, making them louder for auscultation. Detailed information, though, on the BP measurement devices and techniques used in the study by Hedman et al 6 were not provided, challenging the reproducibility of the findings. Despite the added prognostic precision provided by the findings that a higher SBP/MET slope was associated with worse survival, the underlying cause for this association remains elusive.…”

Rays of light into the ‘black-box’ of exercise hypertension

“…7 Exaggerated SBP response to exercise has also been demonstrated to be associated with an increased risk of sudden cardiac death in men without a history of CVD compared with those with normal SBP response to exercise testing (HR 1.73, 95% CI 1.07-2.82). 11 The results of a recently published study 12 including a large cohort of male subjects (N ¼ 7298; 58.6 AE 11.0 years; follow-up 18.4 years) revealed a higher workload-indexed SBP response to exercise rather than a higher peak SBP to be predictive of all-cause mortality. Furthermore, the authors suggested it might be time to rethink the threshold of 'normal' SBP response to progressive exercise.…”