Outcome domains of patient-reported outcome measures used in randomised controlled trials for older adults with non-specific low back pain: a systematic review

OBJECTIVE: To summarise outcome domains and patient-reported outcome measures used in randomised controlled trials involving older adults with non-specific low back pain. METHODS: Seven databases were searched from inception to January 2025. Two independent reviewers screened articles, extracted data and categorised patient-reported outcome measures into outcome domains using the Dodd et al. 38-item framework, where pain outcomes for non-specific pain are classified as 'general outcome', which we have relabelled as 'pain' for clarity. Frequencies of patient-reported outcome measure use and domain coverage were analysed. Adherence to core outcome set domains (physical functioning, pain and health-related quality of life) and core outcome measurement set for non-specific low back pain was evaluated. RESULTS: From 57 included trials, 74 patient-reported outcome measures were identified across nine outcome domains. Physical functioning (n = 80, 36%) and pain (n = 57, 26%) were the most frequently assessed. The most frequently used patient-reported outcome measures were the Roland-Morris Disability Questionnaire and the Visual Analogue Scale. Measures for physical functioning, pain and health-related quality of life were used in 91%, 86% and 23% of studies, respectively. Only 14% addressed all three-core outcome set domains; none adhered fully to the core outcome measurement set. CONCLUSIONS: Trials involving older adults with non-specific low back pain mainly evaluated pain and physical functioning, with limited coverage of other patient-centred domains. Future research should prioritise: (i) standardising outcome measurement with valid, reliable and responsive instruments; and (ii) developing and validating comprehensive, multi-domain outcome measures.