RT Journal Article SR Electronic T1 Application of minimal important differences in degenerative knee disease outcomes: a systematic review and case study to inform BMJ Rapid Recommendations JF BMJ Open JO BMJ Open FD British Medical Journal Publishing Group SP e015587 DO 10.1136/bmjopen-2016-015587 VO 7 IS 5 A1 Tahira Devji A1 Gordon H Guyatt A1 Lyubov Lytvyn A1 Romina Brignardello-Petersen A1 Farid Foroutan A1 Behnam Sadeghirad A1 Rachelle Buchbinder A1 Rudolf W Poolman A1 Ian A Harris A1 Alonso Carrasco-Labra A1 Reed A C Siemieniuk A1 Per O Vandvik YR 2017 UL http://bmjopen.bmj.com/content/7/5/e015587.abstract AB Objectives To identify the most credible anchor-based minimal important differences (MIDs) for patient important outcomes in patients with degenerative knee disease, and to inform BMJ Rapid Recommendations for arthroscopic surgery versus conservative managementDesign Systematic review.Outcome measures Estimates of anchor-based MIDs, and their credibility, for knee symptoms and health-related quality of life (HRQoL).Data sources MEDLINE, EMBASE and PsycINFO.Eligibility criteria We included original studies documenting the development of anchor-based MIDs for patient-reported outcomes (PROs) reported in randomised controlled trials included in the linked systematic review and meta-analysis and judged by the parallel BMJ Rapid Recommendations panel as critically important for informing their recommendation: measures of pain, function and HRQoL.Results 13 studies reported 95 empirically estimated anchor-based MIDs for 8 PRO instruments and/or their subdomains that measure knee pain, function or HRQoL. All studies used a transition rating (global rating of change) as the anchor to ascertain the MID. Among PROs with more than 1 estimated MID, we found wide variation in MID values. Many studies suffered from serious methodological limitations. We identified the following most credible MIDs: Western Ontario and McMaster University Osteoarthritis Index (WOMAC; pain: 12, function: 13), Knee injury and Osteoarthritis Outcome Score (KOOS; pain: 12, activities of daily living: 8) and EuroQol five dimensions Questionnaire (EQ-5D; 0.15).Conclusions We were able to distinguish between more and less credible MID estimates and provide best estimates for key instruments that informed evidence presentation in the associated systematic review and judgements made by the Rapid Recommendation panel.Trial registration number CRD42016047912.