Predictors of health-related quality of life after cardiac surgery: a systematic review

High quality surgical care should include mortality, morbidity and patient-centred outcome measurement [1]. However, patient reported outcomes (PRO) are rarely recorded. Even in research contexts, PROs have only been reported in 29% of cardiac surgery trials [2], despite the fact that those experiencing post-operative complications have worse quality of life [3], which can last three years after surgery [4].

Despite clinicians previously considering health-related quality of life (HRQoL) less important that clinical measures [5], globally health ministers have stated the need to invest in measures that matter most to people [6]. HRQoL measurement allows a holistic, patient-centred perspective of recovery and it is becoming increasingly recognised that HRQoL is important in determining surgical success both from the patients [7] and health-care commissioners [8] perspective.

Factors that predict cardiac surgery mortality do not predict post-operative HRQoL outcome [9]. Thus, an understanding of the factors that do predict HRQoL would be useful to inform patients of the implications of surgery and interventions to improve potentially modifiable predictors could be implemented. Certainly in the UK, HRQoL, and factors associated with it, was identified as the top ten research priority for adult cardiac surgery research [10]. We therefore undertook a literature review to ascertain the predictors of HRQoL after cardiac surgery, to identify potentially modifiable predictors that could be targeted for intervention.

The inclusion, measurement and use of HRQoL and PRO in routine cardiac surgery practice is lacking. Healthcare organisations need to work with patients to deliver more person-centred care, sharing decision-making, to meaningfully improve care outcomes [36]. The ‘holy grail’ of prognostic factor research is to improve patient outcomes by providing a personalised approach to healthcare and risk prediction and how such factors could be used to improve patient or treatment outcomes [37]. Thus, we sought to identify known predictors for HRQoL outcome after cardiac surgery, specifically to focus on modifiable factors where interventions to improve patient or treatment outcomes could be targeted. We identified 41 studies, which were predominantly European-based single-centre prospective observational studies conducted in CABG patients. Certainly, recognition of the non-modifiable predictors found to be particularly impactful both on short and longer-term HRQoL (age, angina, COPD, diabetes, gender, hypertension and NYHA class and peripheral vascular disease) may assist in identifying high risk patients and the identification of interventions and associated resources that might then be directed to assisting these patients to recover. In terms of potential modifiable predictors, pre-operative factors include alcohol use, smoking, BMI/weight depression, and pre-operative quality of life, while ongoing pain management, prevention of post-operative complications and general strategies to reduce ICU and hospital length of stay could also be beneficial.

Individually focused lifestyle and therapeutic interventions have shown effectiveness in weight and BMI reduction [38], decreasing alcohol consumption [39], psychological preparation (including depression and anxiety) [40] and smoking cessation [41]. Given that BMI [42], alcohol use [43], depression and anxiety [44] and smoking [45] have also been identified to be associated with many in-hospital post-operative complications, strategies to encourage their reduction are likely to have beneficial impacts on improving overall morbidity and general recovery. As yet, interventions specifically targeting pre-operative HRQoL do not exist. While most tools combine physical, mental and social wellbeing traditionally greater emphasis clinically has placed on physical health. Nonetheless, the importance of psychological readiness and inclusion of social support and anxiety reduction in prehabilitation programmes is now recognised as part of cardiac surgery enhanced recovery [46]. Furthermore, we found that severe pain during the ICU stay was an independent predictor of HRQoL at six months [47], while high pain scores at 15 months were predictive of HRQoL eight years after surgery in elderly patients [48]. Since up to 10% of cardiac surgery patients develop severe chronic post-surgical pain [49], with predictors of chronic pain including early severe pain [50] personalised effective pain management is vital. Current recommendations suggest the use of multimodal opioid-sparing pain management alongside the use of a pain assessment tool to ensure the lowest opioid dose [46].

Certainly, future work requires more methodologically robust studies, including large multi-site studies with appropriate control of confounding factors. However, generally a greater emphasis on HRQoL as an outcome measure after cardiac surgery, both clinically and in research, is needed. Although HRQoL has been previously undervalued by clinicians [5], the landscape is changing with the importance of HRQoL now recognised in cardiac surgery clinical guidelines [51], the enhanced recovery recommendations [46], the cardiac surgery core outcome dataset [52] and that PROs are included in the Swedish national registers [53] and emerging in the USA STS National Database [54]. Similarly, HRQoL is reported as a top research priority in cardiac surgery, both in the UK [10] and in the USA [55]. Therefore, our review is timely, in that it collates the available evidence on predictors of HRQoL, highlights potential modifiable factors on which interventions could be based in improve patient outcome and emphasises where greater research quality in prognosis factor research should reside in this area.