Initial Evidence for Reliable and Valid Use of Scores on the 8-Item Econ-QOL Short Form to Measure Economic Quality of Life in Caregivers of Persons With Traumatic Brain Injury

Abstract

Objective: To provide reliability and validity data to support the clinical utility of Economic Quality of Life Measure (Econ-QOL) scores in caregivers of civilians and service members/veterans with traumatic brain injury (TBI).

Design: Cross-sectional survey study.

Setting: Three academic medical centers and a Veterans Affairs treatment facility.

Participants: 376 caregivers of civilians (n=213) and service members/veterans (n=163) with TBI (N=376).

Interventions: N/A.

Main outcome measures: Econ-QOL and several patient-reported outcome measures (Traumatic Brain Injury Caregiver Quality of Life Caregiver-Specific Anxiety and Caregiver Strain, Patient-Reported Outcomes Measurement Information System sleep-related impairment, Neurological Quality of Life Measurement System positive affect and well-being) and measures of financial status (self-reported income).

Results: Internal consistency reliability of the Econ-QOL Short Form scores were excellent (all Cronbach's alphas ≥.92). There were no floor or ceiling effects for scores. There was evidence of convergent and discriminant validity, with the Econ-QOL scores having the strongest relationships with self-reported income (convergent validity evidence) and weak relationships with the other measures (discriminant validity evidence). Individuals with scores that were "below or possibly below" the poverty line (according to 2016 federal government poverty level thresholds) reported worse economic quality of life relative to those individuals who were definitely above the poverty line, supporting known-groups validity.

Conclusions: This article establishes the clinical utility of scores on the Econ-QOL Short Form in caregivers of persons with TBI and provides evidence that it is valid and appropriate to use such scores not only in a variety of different disability populations (eg, spinal cord injury, stroke) but also in caregivers.

Keywords: Brain injuries, traumatic; Caregivers; Economic factors; Patient-reported outcome measures; Psychometrics; Quality of life; Rehabilitation; Reproducibility of results; Surveys and questionnaires; Veterans.