Measurement properties of selected patient-reported outcome measures for use in randomised controlled trials in patients with systemic lupus erythematosus: a systematic review

Abstract

OBJECTIVE The heterogeneous multisystem manifestations of SLE include fatigue, pain, depression, sleep disturbance and cognitive dysfunction, and underscore the importance of a multidimensional approach when assessing health-related quality of life. The US Food and Drug Administration has emphasised the importance of patient-reported outcomes (PROs) for approval of new medications and Outcome Measures in Rheumatology has mandated demonstration of appropriate measurement properties of selected PRO instruments. METHODS Published information regarding psychometric properties of the Medical Outcomes Survey Short Form 36 (SF-36), Lupus Quality of Life Questionnaire (LupusQoL) and Functional Assessment of Chronic Illness Therapy-Fatigue Scale (FACIT-F), and their suitability as end points in randomised controlled trials (RCTs) and longitudinal observational studies (LOS) were assessed. A search of English-language literature using MEDLINE and EMBASE identified studies related to development and validation of these instruments. Evidence addressed content validity, reliability (internal consistency and test-retest reliability), construct validity (convergent and divergent) and longitudinal responsiveness, including thresholds of meaning and discrimination. RESULTS All instruments demonstrated strong internal consistency, reliability and appropriate face/content validity, indicating items within each instrument that measure the intended concept. SF-36 and LupusQoL demonstrated test-retest reliability; although not published with FACIT-F in SLE supported by evidence from other rheumatic diseases. All instruments demonstrated convergent validity with other comparable PROs and responsivity to treatment. CONCLUSION The measurement properties of PRO instruments with published data from RCTs including: SF-36, LupusQoL and FACIT-F indicate their value as secondary end points to support labelling claims in RCTs and LOS evaluating the efficacy of SLE treatments.