Submaximal fitness and mortality risk reduction in coronary heart disease: A retrospective cohort study of community-based exercise rehabilitation

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

Abstract

Objectives To examine the association between submaximal cardiorespiratory fitness (sCRF) and all-cause mortality in a cardiac rehabilitation (CR) cohort. Design Retrospective cohort study of participants entering CR between 26 May 1993 and 16 October 2006, followed up to 1 November 2013 (median 14 years, range 1.2–19.4 years). Setting A community-based CR exercise programme in Leeds, West Yorkshire, UK. Participants A cohort of 534 men (76%) and 136 women with a clinical diagnosis of coronary heart disease (CHD), aged 22–82 years, attending CR were evaluated for the association between baseline sCRF and all-cause mortality. 416 participants with an exercise test following CR (median 14 weeks) were examined for changes in sCRF and all-cause mortality. Main outcome measures All-cause mortality and change in sCRF expressed in estimated metabolic equivalents (METs). Results Baseline sCRF was a strong predictor of all-cause mortality; compared to the lowest sCRF group (<5 METs for women and <6 METs for men), mortality risk was 41% lower in those with moderate sCRF (HR 0.59; 95% CI 0.42 to 0.83) and 60% lower (HR 0.40; 95% CI 0.25 to 0.64) in those with higher sCRF levels (≥7 METs women and ≥8 METs for men). Although improvement in sCRF at 14 weeks was not associated with a significant mortality risk reduction (HR 0.91; 95% CI 0.79 to 1.06) for the whole cohort, in those with the lowest sCRF (and highest all-cause mortality) at baseline, each 1-MET improvement was associated with a 27% age-adjusted reduction in mortality risk (HR 0.73; 95% CI 0.57 to 0.94). Conclusions Higher baseline sCRF is associated with a reduced risk of all-cause mortality over 14 years in adults with CHD. Improving fitness through exercise-based CR is associated with significant risk reduction for the least fit.

Citation

Taylor, C., Tsakirides, C., Moxon, J., Moxon, J. W., Dudfield, M., Witte, K. K., Ingle, L., & Carroll, S. (2016). Submaximal fitness and mortality risk reduction in coronary heart disease: A retrospective cohort study of community-based exercise rehabilitation. BMJ open, 6(6), Article e011125. https://doi.org/10.1136/bmjopen-2016-011125

• Acceptance Date: May 19, 2016
• Online Publication Date: Jun 30, 2016
• Publication Date: Jun 1, 2016
• Deposit Date: Jul 5, 2016
• Publicly Available Date: Jul 5, 2016
• Journal: BMJ open
• Print ISSN: 2044-6055
• Publisher: BMJ Publishing Group
• Peer Reviewed: Peer Reviewed
• Volume: 6
• Issue: 6
• Article Number: e011125
• DOI: https://doi.org/10.1136/bmjopen-2016-011125
• Keywords: Coronary heart disease; Heart disease; Submaximal fitness; Mortality risk reduction
• Public URL: https://hull-repository.worktribe.com/output/440630
• Publisher URL: http://bmjopen.bmj.com/content/6/6/e011125
• Additional Information: Copy of article first published in: BMJ open, 2016, v.6, issue 6
• Contract Date: Jul 5, 2016