Patient-reported outcomes in randomized controlled trials of spinal disorders: a methodological quality assessment and recommendations for future research

Purpose: This study aimed to assess the types of PRO instruments used and evaluate the overall quality of PRO reporting in RCTs addressing spinal disorders. Methods: A systematic literature search of PubMed and Web of Science was conducted to identify RCTs reporting PROs in spinal conditions. Trials were screened according to PRISMA guidelines, and the quality of PRO reporting was evaluated using the ISOQOL-recommended checklist. Descriptive analyses and multivariable linear regression were performed to explore predictors of reporting quality. Results: A total of 42 RCTs involving 8,669 participants were included. Most trials (95.2%) designated PROs as primary outcomes, with lumbar degenerative diseases being the most common focus (45.2%). Across studies, 25 distinct PRO tools were identified and grouped into five domains: pain, functional disability, quality of life, patient experience, and psychological assessment. The Visual Analog Scale (VAS) and Oswestry Disability Index (ODI) were the most frequently used instruments. However, tools assessing psychological domains were underutilized. Reporting adherence was higher when PROs were primary outcomes, but only 27.2% of studies met high-quality reporting standards. Critical deficiencies were noted in justifying instrument selection, data collection modalities, and handling of missing data. Regression analysis revealed no statistically significant predictors of reporting quality. Conclusion: Despite the widespread inclusion of PROs in spinal disorder RCTs, major methodological gaps persist in reporting practices. Enhancing standardization in PRO tool selection, data collection methods, and statistical handling of missing data is essential for improving the validity, comparability, and clinical impact of PRO-based evidence in spinal health research.