Exercise dose and all-cause mortality within extended cardiac rehabilitation: a cohort study

Taylor, Claire; Tsakirides, Costas; Moxon, James; Moxon, James W.; Dudfield, Michael; Witte, Klaus; Ingle, Lee; Carroll, Sean

Abstract

Aims: To investigate the relationship between exercise participation, exercise ‘dose’ expressed as metabolic equivalent (MET) hours (h) per week, and prognosis in individuals attending an extended, community-based exercise rehabilitation programme. Methods: Cohort study of 435 participants undertaking exercise-based cardiac rehabilitation (CR) in Leeds, West Yorkshire, UK between 1993 and 2006, followed up to 1 November 2013. MET intensity of supervised exercise was estimated utilising serial submaximal exercise test results and corresponding exercise prescriptions. Programme participation was routinely monitored. Cox regression analysis including time-varying and propensity score adjustment was applied to identify predictors of long-term, all-cause mortality across exercise dose and programme duration groups. Results: There were 133 events (31%) during a median follow up of 14 years (range, 1.2 to 18.9 years). The significant univariate association between exercise dose and all-cause mortality was attenuated following multivariable adjustment for other predictors, including duration in the programme. Longer-term adherence to supervised exercise training (> 36 months) was associated with a 33% lower mortality risk (multivariate-adjusted hazard ratio: 0.67; 95% confidence interval: 0.47 to 0.97; p=0.033) compared to all lesser durations of CR (3, 12, 36 months), even after adjustment for baseline fitness, comorbidities and survivor bias. Conclusion: Exercise dose (MET-h per week) appears less important than long-term adherence to supervised exercise for the reduction of long-term mortality risk. Extended, supervised CR programmes within the community may play a key role in promoting long-term exercise maintenance and other secondary prevention therapies for survival benefit.

Citation

Taylor, C., Tsakirides, C., Moxon, J., Moxon, J. W., Dudfield, M., Witte, K., Ingle, L., & Carroll, S. (2017). Exercise dose and all-cause mortality within extended cardiac rehabilitation: a cohort study. Open heart, 4(2), e000623. https://doi.org/10.1136/openhrt-2017-000623

• Journal Article Type: Article
• Acceptance Date: Jun 20, 2017
• Online Publication Date: Jul 28, 2017
• Publication Date: Jul 1, 2017
• Deposit Date: Jun 28, 2017
• Publicly Available Date: Jul 1, 2017
• Journal: Open heart
• Electronic ISSN: 2053-3624
• Publisher: BMJ Publishing Group
• Peer Reviewed: Peer Reviewed
• Volume: 4
• Issue: 2
• Pages: e000623
• DOI: https://doi.org/10.1136/openhrt-2017-000623
• Keywords: Survival, Submaximal exercise testing, Fitness, Exercise volume
• Public URL: https://hull-repository.worktribe.com/output/453094
• Publisher URL: http://openheart.bmj.com/content/4/2/e000623
• Additional Information: Copy of article first published in: Open heart, v.4, issue 2
• Contract Date: Jun 28, 2017