• cardiac rehabilitation

It’s not the years in your life that matter, it’s the life in your years.

This (mis)quote neatly captures the importance of quality of life. Indeed, our quality of life has perhaps never been so important than during these unprecedented times of the COVID-19 pandemic.

Although limited, there is some empirical evidence to support the value that people with heart disease attach to their health-related quality of life (HRQoL). An innovative study asked 99 people with advanced heart failure to complete a time trade-off (TTO) tool to quantify their willingness to trade time (length of life) for better health (HRQoL).1 TTO scores can range from 1.0 (no willingness to trade off length of life for health) to 0 (complete willingness to trade off length of life for health). Importantly, the study authors found that patients were prepared to trade off time for health, and interestingly this trade-off was greatest for those with the poorest HRQoL (eg, patients with an New York Heart Association (NYHA) score of IV reported a mean TTO score of 0.66–0.69). While ‘hard’ clinical trial outcomes such as mortality and hospitalisation have traditionally been used to judge the value of new and existing treatments for heart disease, there is an increasing call for the regulatory approval of new treatments to include formal consideration of impacts on patient-related outcomes, especially HRQoL.2

When we ask our patients why they want to participate in cardiac rehabilitation (CR), the response that we invariably hear is that they do so because they want to be able to better undertake their activities and roles of daily life—in other words, patients undertake CR to improve their HRQoL. This is also reflected in the core standards of the British Association for Cardiovascular Prevention and Rehabilitation, noting that while optimal medical therapy and percutaneous intervention for management of coronary heart disease add ‘years to life’, the potential for CR to add ‘life to years’ should not be underestimated.3

Although we have evidence from our Cochrane review of randomised controlled trials that, overall, people with coronary heart disease following CR have superior HRQoL compared with (no CR) controls, the strength of this evidence is not all that we might want it to be.4 5 To date, only few trials (20 trials in 5060 patients out of 63 trials randomising 14 486 patients) have collected and reported HRQoL, and when they do there has been little consistency in the HRQoL outcomes collected, often limited to short-term follow-up.

The study by Hurdus and colleagues6 published in the current issue of Heart provides important confirmatory evidence of the benefits of CR on the HRQoL. The study was based on a large longitudinal prospective cohort study (Evaluation of the Methods and Management of Acute Coronary Events-3), with data on the referral and uptake of CR in England from 4570 patients admitted with an acute myocardial infraction between 1 November 2011 and 17 September 2013. Uniquely, this study provides repeated measures data on the impact of CR on HRQoL collected using the EuroQol (EQ-5D-3L) at hospitalisation, 30 days, 6 months and 12 months following hospital discharge. Across all patients with acute myocardial infraction, the authors report a small improvement in mean EQ-5D index score from hospitalisation to 12 months (0.744 vs 0.794). They also found that those who attended CR had greater mean EQ-5D score at 12 months (0.832 vs 0.739) and consistent over time following hospitalisation. These HRQoL improvements with CR participation were not only statistically significant but also clinically important. Reassuringly, Hurdus et al 6 also found those achieving ≥150 min of activity per week (a marker of CR adherence) achieved the largest improvements in HRQoL. Although the authors acknowledge that these observational findings require confirmation in a randomised trial, robust scientific methods were employed by this study group, with potential selection bias and confounding minimised by use of a weighted propensity score analysis.

As recognised in a recent editorial, we still have much work to do to agree on what level of improvement of HRQoL we would exchange for a reduction in quantity of life.7 However, in the mean time, future evidence collection (trials and observational studies) assessing the impact of CR needs to assess and report HRQoL using generic and disease-specific instruments. Although challenging, consensus in the CR field on the HRQoL measures that we should collect would aid this endeavour and allow us to directly compare results between studies and pool data across studies using standard meta-analytic approaches.