Validation and reliability of the Abbreviated World Health Organization Quality of Life Instrument (WHOQOL-BREF) in the hospitalized trauma population.

INTRODUCTION: While the number of trauma patients surviving their injury increase, it is important to measure Quality of Life (QoL). The Abbreviated World Health Organization Quality of Life (WHOQOL-BREF) questionnaire can be used to assess QoL. However, its psychometric properties in trauma patients are unknown and therefore, we aimed to investigate the validity and reliability of the WHOQOL-BREF for the hospitalized trauma population. METHODS: Data were derived from the Brabant Injury Outcome Surveillance. Floor and ceiling effects and missing values of the WHOQOL-BREF were examined. Confirmatory factor analysis (CFA) was performed to examine the underlying 4 dimensions (i.e. physical, psychological, social and environmental) of the questionnaire. Cronbach's alpha (CA) was calculated to determine internal consistency. In total, 42 hypotheses were formulated to determine construct validity and 6 hypotheses were created to determine discriminant validity. To determine construct validity, Spearman's correlations were calculated between the WHOQOL-BREF and the EuroQol-five-dimension-3-level questionnaire, the Health Utility Index Mark 2 and 3, the Hospital Anxiety and Depression Scale and the Impact of Event Scale. Discriminant validity between patients with minor injuries (i.e. Injury Severity Score (ISS)≤8) and moderate/severe injuries (i.e. ISS ≥ 9) was examined by conducting Mann-Whitney-U-tests. RESULTS: In total, 202 patients (median 63y) participated in this study with a median of 32 days (interquartile range 29-37) post-trauma. The WHOQOL-BREF showed no problematic floor and ceiling effects. The CFA revealed a moderate model fit. The domains showed good internal consistency, with the exception of the social domain. All individual items and domain scores of the WHOQOL-BREF showed nearly symmetrical distributions since mean scores were close to median scores, except of the 'general health' item. The highest percentage of missing values was found on the 'sexual activity' item (i.e. 19.3%). The WHOQOL-BREF showed moderate construct and discriminant validity since in both cases, 67% of the hypotheses were confirmed. CONCLUSION: The present study provides support for using the WHOQOL-BREF for the hospitalized trauma population since the questionnaire appears to be valid and reliable. The WHOQOL-BREF can be used to assess QoL in a heterogeneous group of hospitalized trauma patients accurately. TRAIL REGISTRATION: ClinicalTrials.gov identifier: NCT02508675.