References

1. Prins C, de Villiers Jonker I, et al. Cardiac surgery risk-stratification models. Cardiovasc J Afr. 2012;23(3):160–4.
2. Nashef SA, Roques F, Michel P, et al. European system for cardiac operative risk evaluation (EuroSCORE). Eur J Cardiothorac Surg. 1999;16(1):9–13.
3. Nashef SAM, Roques F, Sharples LD, et al. Euroscore II. Eur J Cardio-thoracic Surg. 2012;41(4):734–45.
4. Garcia-Valentin A, Mestres CA, Bernabeu E, et al. Validation and quality measurements for EuroSCORE and EuroSCORE II in the Spanish cardiac surgical population: a prospective, multicentre study†. Eur J Cardiothorac Surg. 2015;49:399–405.
5. Borracci RA, Rubio M, Celano L, et al. Prospective validation of EuroSCORE II in patients undergoing cardiac surgery in Argentinean centres. Interact Cardiovasc Thorac Surg. 2014;18(5):539–43.
6. Zhang G, Wang C, Wang L, et al. Validation of EuroSCORE II in Chinese Patients Undergoing Heart Valve Surgery. Hear Lung Circ. 2013;22(8):606–11.
7. Cromhout PF, Moons P, Thygesen LC, et al. Time to expand risk evaluation systems for cardiac surgery? Looking beyond physiological parameters. Eur J Cardiovasc Nurs. 2018;17(8):760–6.
8. Cromhout PF, Berg SK, Moons P, et al. Updating EuroSCORE by including emotional, behavioural, social and functional factors to the risk assessment of patients undergoing cardiac surgery: a study protocol. BMJ Open. 2019;9:26745.
9. Lynge E, Sandegaard JL, Rebolj M. The Danish National Patient Register. Scand J Public Health. 2011;39(7 Suppl):30–3.
10. Pedersen CB. The Danish Civil Registration System. Scand J Public Health. 2011;39(7 Suppl):22–5.
11. Jensen VM, Rasmussen AW. Danish education registers. Scand J Public Health. 2011;39(7 Suppl):91–4.
12. Baadsgaard M, Quitzau J. Danish registers on personal income and transfer payments. Scand J Public Health. 2011;39(7):103–5.
13. Berg SK, Svanholm J, Lauberg A, et al. Patient-reported outcomes at hospital discharge from Heart Centres, a national cross-sectional survey with a register-based follow-up: the DenHeart study protocol. BMJ Open. 2014;4:4709.
14. Özcan C, Juel K, Lassen JF, et al. The Danish Heart Registry. Clin Epidemiol. 2016;8:503–8.
15. Ware J, Kosinski M, Keller SD. A 12-Item Short-Form Health Survey : Construction of Scales and Preliminary Tests of Reliability and Validity. Med Care. 1996;34(3):220–33.
16. Gandek B, Ware JE, Aaronson NK, et al. Cross-validation of item selection and scoring for the SF-12 Health Survey in nine countries: results from the IQOLA Project. International Quality of Life Assessment. J Clin Epidemiol. 1998;51(11):1171–8.
17. Oldridge N, Hofer S, McGee H, et al. The HeartQoL: Part I. Development of a new core health-related quality of life questionnaire for patients with ischemic heart disease. Eur J Prev Cardiol. 2014;21(1):90–7.
18. Broadbent E, Petrie KJ, Main J, et al. The brief illness perception questionnaire. J Psychosom Res. 2006;60(6):631–7.
19. Christensen AI, Ekholm O, Glümer C, et al. The Danish National Health Survey 2010. Study design and respondent characteristics. Scand J Public Health. 2012;40(4):391–7.
20. Myles PS. Meaningful outcome measures in cardiac surgery. J Extra Corpor Technol. 2014;46(1):23–7.
21. Hannan EL, Racz MJ, Walford G, et al. Predictors of readmission for complications of coronary artery bypass graft surgery. JAMA. 2003;290(6):773–80.
22. Iribarne A, Chang H, Alexander JH, et al. Readmissions after cardiac surgery: Experience of the national institutes of health/canadian institutes of health research cardiothoracic surgical trials network. Ann Thorac Surg. 2014;98:1274–80.
23. Sibilitz KL, Berg SK, Thygesen LC, et al. High readmission rate after heart valve surgery: A nationwide cohort study. Int J Cardiol. 2015;189:96–104.
24. Almashrafi A, Alsabti H, Mukaddirov M, et al. Factors associated with prolonged length of stay following cardiac surgery in a major referral hospital in Oman: a retrospective observational study. BMJ Open. 2016;6(6):e010764.
25. Papachristofi O, Klein AA, Mackay J, et al. Effect of individual patient risk, centre, surgeon and anaesthetist on length of stay in hospital after cardiac surgery: Association of Cardiothoracic Anaesthesia and Critical Care (ACTACC) consecutive cases series study of 10 UK specialist centres. BMJ Open. 2017;7:e016947.
26. Azarfarin R, Ashouri N, Totonchi Z, et al. Factors influencing prolonged ICU stay after open heart surgery. Res Cardiovasc Med. 2014;3(4):e20159.
27. Atoui R, Ma F, Langlois Y, et al. Risk factors for prolonged stay in the intensive care unit and on the ward after cardiac surgery. J Card Surg. 2008;23(2):99–106.
28. Ettema RGA, Peelen LM, Schuurmans MJ, et al. Prediction models for prolonged intensive care unit stay after cardiac surgery: systematic review and validation study. Circulation. 2010;122(7):682–9.
29. Janssen DPB, Noyez L, Wouters C, et al. Preoperative prediction of prolonged stay in the intensive care unit for coronary bypass surgery. Eur J Cardiothorac Surg. 2004;25(2):203–7.
30. Harrell FE, Califf RM, Pryor DB, et al. Evaluating the yield of medical tests. JAMA. 1982;247(18):2543–6.
31. Gerds TA, Cai T, Schumacher M. The performance of risk prediction models. Biometrical J. 2008;50(4):457–79.
32. Murphy BM, Elliott PC, Le Grande MR, et al. Living alone predicts 30-day hospital readmission after coronary artery bypass graft surgery. Eur J Cardiovasc Prev Rehabil. 2008;15:210–5.
33. King KB, Reis HT. Marriage and long-term survival after coronary artery bypass grafting. Heal Psychol. 2012;31(1):55–62.
34. Dickens CM, McGowan L, Percival C, et al. Lack of a close confidant, but not depression, predicts further cardiac events after myocardial infarction. Heart. 2004;90(5):518–22.
35. Haustein K-O. Smoking and poverty. Eur J Cardiovasc Prev Rehabil. 2006;13(3):312–8.
36. Schwarz B, Schoberberger R, Rieder A, et al. Factors delaying treatment of acute myocardial infarction. Eur Heart J. 1994;15(12):1595–8.
37. DiMatteo MR, Lepper HS, Croghan TW. Depression is a risk factor for noncompliance with medical treatment: meta-analysis of the effects of anxiety and depression on patient adherence. Arch Intern Med. 2000;160(14):2101–7.
38. Herlitz J, Wiklund I, Caidahl K, et al. The Feeling of Loneliness Prior to Coronary Artery Bypass Grafting Might be a Predictor of Short-and Long-term Postoperative Mortality. Eur J Vasc Endovasc Surg. 1998;16:120–5.
39. Olsen RB, Olsen J, Gunner-Svensson F, et al. Social networks and longevity. A 14 year follow-up study among elderly in Denmark. Soc Sci Med. 1991;33(10):1189–95.
40. Tully PJ. Quality-of-Life measures for cardiac surgery practice and research: a review and primer. J Extra Corpor Technol. 2013;45(1):8–15.
41. Noyez L, de Jager MJ, Markou ALP. Quality of life after cardiac surgery: underresearched research. Interact Cardiovasc Thorac Surg. 2011;13(5):511–4.
42. Grady KL, Lee R, Subačius H, et al. Improvements in Health-Related Quality of Life Before and After Isolated Cardiac Operations. Ann Thorac Surg. 2011;91:777–83.
43. Rumsfeld JS, MaWhinney S, McCarthy M, et al. Health-Related Quality of Life as a Predictor of Mortality Following Coronary Artery Bypass Graft Surgery. JAMA. 1999;281(14):1298–303.
44. Falcoz P-E, Chocron S, Stoica L, et al. Open Heart Surgery: One-Year Self-Assessment of Quality of Life and Functional Outcome. Ann Thorac Surg. 2003;76:1598–604.
45. Berg SK, Thorup CB, Borregaard B, et al. Patient-reported outcomes are independent predictors of one-year mortality and cardiac events across cardiac diagnoses: Findings from the national DenHeart survey. Eur J Prev Cardiol. 2018;204748731876976.
46. Steyerberg EW. Clinical Prediction Models A Practical Approach to Development, Validation, and Updating. Vol. 36. New York: Springer Science & Business Media; 2005.
47. Austin PC, Tu J V. Automated variable selection methods for logistic regression produced unstable models for predicting acute myocardial infarction mortality. J Clin Epidemiol. 2004;57:1138–46.