A comparison of three quality-of-life measurement tools in out-of-hospital cardiac arrest survivors: A report from the Victorian Ambulance Cardiac Arrest Registry

Abstract

Introduction: Quality of life (QOL) research is relatively new in the field of out-of-hospital cardiac arrest (OHCA) and few healthrelated QOL (HRQOL) tools have been validated in this population. The Victorian Ambulance Cardiac Arrest Registry (VACAR) assesses theQOLand functional recoveryofOHCAsurvivors’ 12-monthspost arrest. We sought tomeasure the correlation between instruments utilised, and assess their validity in the OHCA population. Methods:Telephone interviewswere conductedwith adult survivors who arrested between 1 January 2010 and 31 December 2013. Instruments included the Euro-QOL 5D (EQ-5D) and Visual Analogue Scale (VAS), Short Form 12 (SF-12), and Glasgow Outcome Scale–Extended (GOSE). The SF-6D score was also derived from patients’ SF-12 responses. Floor and ceiling effects of EQ-5D, SF-12 and SF-6D outcome scores were assessed. Spearman’s rho correlationcoefficientwasused toassess correlationbetween tools. Results: A total of 932 patients/proxies participated. No floor effects were observed, however a ceiling effect of 42.6% was observed for the EQ-5D summary score of patients, compared with 23.8% for proxies. The SF-6D correlated well with the EQ5D summary score (0.632, p<0.01) and SF-12 Physical Component Summary (0.692, p<0.01). However, the SF-12 Mental Component Summary correlated poorly with EQ-5D summary score and VAS (<0.300). For patients achieving a GOSE outcome ≥5, the distribution of SF-6D and EQ-5D summary scores were observed to differ significantly within each GOSE category (p<0.001). Discussion: The EQ-5D index score yielded a large ceiling effect and thus performed poorly in the OHCA population. Varying correlation between instruments may be explained by differences in the content of instruments or the sensitivity of individual tools within this population. However further investigation is important to determine the appropriateness and validity of HRQOL and functional recovery tools in OHCA populations.