Minimally important difference estimates and assessment of its credibility for patient reported outcomes in adults: a systematic survey

Tags: Oral
Carrasco- Labra A1, Johnston BC2, Ebrahim S2, Furukawa TA3, Patrick DL4, Hemmelgarn BR5, Motaghi Pisheh S1, Dennis B1, Jacobs M6, Vernooij RW7, Fei Y8, Younho Hong B1, Tajika A3, Takeshima N3, Iwakami N3, Hayasaka Y3, Kaminski-Hartenthaler A9, Nussbaumer B9, Colunga L10, Devji T1, Gartlehner G9, Schunemann HJ1, Guyatt G1, Nesrallah G11
1Department of Clinical Epidemiology & Biostatistics, McMaster University, Canada, 2Department of Anaesthesia and Pain Medicine, The Hospital for Sick Children; Department of Clinical Epidemiology & Biostatistics, McMaster University, Canada, 3Department of Health Promotion and Human Behavior, School of Public Health, Kyoto University Graduate School of Medicine, Japan, 4Seattle Quality of Life Group, Department of Health Services, University of Washington, USA, 5Faculty of Medicine, University of Calgary, Canada, 6Department of Medical Psychology J3-220-1, Academic Medical Center, The Netherlands, 7Iberoamerican Cochrane Centre, Institute of Biomedical Research (IIB Sant Pau) , Spain, 8Centre for Evidence-Based Chinese Medicine, Beijing University of Chinese Medicine, Department of Clinical Epidemiology & Biostatistics, McMaster University, China, 9Department for Evidence-Based Medicine and Clinical Epidemiology, Danube University, Krems , Austria, 10Hospital Civil de Guadalajara, Fray Antonio Alcalde, Mexico, 11Nephrology Program, Humber River Regional Hospital; Division of Nephrology, University of Western Ontario, Canada

Background: Patient-reported outcomes (PROs) have the function of reflecting patients’ perspectives on treatment benefits and harms. The ability to interpret and, consequently, include PROs in the decision-making process along with other patient-important outcomes relies on the understanding of what improvement or reduction in the PRO represents a change that is considered important to patients. The most common reference point for interpretation of PROs is the minimal important difference (MID), which provides a measure of the smallest change in a PRO that patients would perceive as an important benefit or harm.

Objective: To document published anchor-based MIDs associated with PRO instruments used in evaluating the effects of interventions on chronic medical and psychiatric conditions in both adult and pediatric populations.

Methods: We are currently launching a study that summarizes and appraises available methods to estimate anchor-based MIDs. We will also document all anchor-based MIDs reported for adults and pediatric populations and will develop a rating instrument to assess their credibility. We will create an inventory of available anchor-based MIDs, including the context in which they were assessed (condition/disease), and the confidence users can place in a particular MID. We will search MEDLINE, EMBASE, PsycINFO, and CINAHL (1989 to present) to identify studies addressing methods to estimate anchor-based MIDs of PRO instruments or reporting empirical ascertainment of anchor-based MIDs. Teams of two reviewers will independently screen citations identified, and extract relevant data.

Discussion: No inventory of MIDs is currently available, which means that clinicians and patients have to navigate the vast literature in order to retrieve a specific MID. Even if they find an apparently applicable MID, there is no guidance regarding the extent to which users can trust the reported MID. We will provide a summary of the available MIDs in the literature and describe their overall credibility.