Author + information
- Martin G. Schultz, PhD,
- Petr Otahal, GDipAppStat,
- Dean S. Picone, BMedRes (Hons) and
- James E. Sharman, PhD∗ ()
- ↵∗Menzies Institute for Medical Research, University of Tasmania, Private Bag 23, Hobart, 7000, Australia
Exercise stress testing is routinely used to assess cardiovascular risk, and measurement of blood pressure (BP) during the test is a standard component of patient monitoring (1). Irrespective of whether BP is considered normal at rest (in-clinic BP <140/90 mm Hg), some individuals may experience abnormal (hypotensive or hypertensive) BP responses during exercise testing. Our recent meta-analyses demonstrated that abnormal BP responses carry significant risk for future cardiovascular events and mortality, independent of resting BP and other cardiovascular risk factors (2,3). Although exercise hypotension is a sign of significant cardiovascular pathology, it is possible that some of the cardiovascular risk associated with exercise hypertension (exaggerated exercise blood pressure [EEBP]) relates to underlying (masked) hypertension (4) gone unnoticed with clinic BP screening, or to future development of overt hypertension detectable with in-clinic BP screening. A pooled summary of studies assessing the relationship between EEBP and incident hypertension has never been undertaken, and is an important step with respect to determining whether EEBP has utility for early identification of people at heightened cardiovascular risk. Therefore, we sought to conduct a systematic review and meta-analysis to determine associations between EEBP and incident hypertension among people with normal resting BP at baseline examination.
We searched 7 online databases for studies measuring dynamic exercise BP that reported incident hypertension (defined from clinic BP ≥140/90 mm Hg) among those normotensive at baseline. Random-effects meta-analysis was applied to pool risk estimates (RE) for incident hypertension on the basis of EEBP defined from the systolic BP during exercise (at moderate or peak intensity), or as the change in systolic BP from rest. Data was analyzed comparing RE on categorical (those with vs. those without EEBP) or continuous (per 10 mm Hg increase) scales.
Quantitative RE were extracted for meta-analysis from 16 studies that met the inclusion criteria, with a total of 23,207 participants (mean age 42.4 ± 7.1 years), followed for 5.3 ± 2.1 years. Several meta-analyses were performed on the basis of different definitions of EEBP. Pooling RE from 5 studies defining EEBP at peak exercise intensity and 4 studies at moderate exercise intensity (adjusted for resting BP, age, sex, and other cardiovascular risk factors), revealed that EEBP (systolic BP) was associated with significantly increased risk for incident hypertension when compared with those without EEBP (Figure 1). Similarly, each 10 mm Hg increase in exercise systolic BP at peak (pooling 2 studies) and moderate (pooling 2 studies) exercise intensity was associated with increased risk of incident hypertension (Figure 1). When pooling 3 studies defining EEBP by change in systolic BP from rest to peak exercise intensity, EEBP was associated with greater risk for incident hypertension (RE: 1.98 [95% confidence interval (CI): 1.19 to 3.31], I2 = 62.0%) compared to those without EEBP. Further pooling of 9 studies that reported RE unadjusted for resting BP or other cardiovascular risk factors (7 from EEBP defined during peak exercise, 2 from EEBP defined at moderate) revealed similar, positive associations between EEBP and incident hypertension (RE: 1.97; [95% CI: 1.57 to 2.46], I2 = 56.9% and RE: 2.26; [95% CI: 1.60 to 3.20], I2 = 16.7%, respectively).
This is the first meta-analysis to demonstrate that EEBP predicts incident hypertension independently of in-clinic resting BP and other cardiovascular risk factors. This analysis provides evidence to support the clinical value of EEBP to detect cardiovascular risk related to BP that would remain otherwise undetectable by conventional (resting) BP measurements. Millions of clinical exercise stress tests are conducted worldwide every year, with BP as a standard measurement. Our findings suggest that EEBP should alert supervising physicians to a heightened level of cardiovascular risk associated with BP, and this should warrant further investigation with respect to BP control and/or lifestyle intervention.
Please note: Dr. Schultz is supported by a post-doctoral research fellowship from the Heart Foundation of Australia (award ID: 100134). Dr. Sharman is supported by a National Health and Medical Research Council of Australia, Australian Clinical Research Fellowship (reference 1045373). The authors have reported that they have no relationships relevant to the contents of this paper to disclose.
- 2015 American College of Cardiology Foundation