How is the minimal clinically important difference established in health-related quality of life instruments? Review of anchors and methods

Abstract

Background: The aim of this systematic review is to describe the different types of anchors and statistical methods used in estimating the Minimal Clinically Important Difference (MCID) for Health-Related Quality of Life (HRQoL) instruments. Methods: PubMed and Google scholar were searched for English and French language studies published from 2010 to 2018 using selected keywords. We included original articles (reviews, meta-analysis, commentaries and research letters were not considered) that described anchors and statistical methods used to estimate the MCID in HRQoL instruments. Results: Forty-seven papers satisfied the inclusion criteria. The MCID was estimated for 6 generic and 18 diseasespecific instruments. Most studies in our review used anchor-based methods (n = 41), either alone or in combination with distribution-based methods. The most common applied anchors were non-clinical, from the viewpoint of patients. Different statistical methods for anchor-based methods were applied and the Change Difference (CD) was the most used one. Most distributional methods included 0.2 standard deviations (SD), 0.3 SD, 0.5 SD and 1 standard error of measurement (SEM). MCID values were very variable depending on methods applied, and also on clinical context of the study. Conclusion: Multiple anchors and methods were applied in the included studies, which lead to different estimations of MCID. Using several methods enables to assess the robustness of the results. This corresponds to a sensitivity analysis of the methods. Close collaboration between statisticians and clinicians is recommended to integrate an agreement regarding the appropriate method to determine MCID for a specific context.

Estimation of minimally important difference of the EQ-5D-5L utility scores among patients with either hypertension or diabetes or both: a cross-sectional study in Hong Kong

“…36 When taken into the policy area, MID estimates could provide evidence regarding whether a treatment is beneficial or harmful to patients and whether information could help health policy-makers to Open access determine the healthcare resource allocation and reimbursement strategy. 37 Moreover, our findings bridge a knowledge gap regarding the influence of sex and age on MID estimates. Despite knowing such diverse results in subjective health and HRQoL, 38 MID reflects an innate difference in patient preferences on HRQoL and well-being.…”

Health related quality of life and satisfaction with care of stroke patients in Budapest: A substudy of the EuroHOPE project

“…Minimally important differences (MIDs) for health state utilities vary by measure and methods, and are not well established [ 49 ]. It has been suggested that for EQ-5D differences among health state utilities of at least 0.036 can be considered clinically important [ 50 ].…”

“…Using the same health state utility measures 3 months after intracerebral hemorrhage, predictors for lower HRQoL by both scales were higher NIHSS and older age, with similar ORs for EQ-5D-5L, and 15D [48]. Minimally important differences (MIDs) for health state utilities vary by measure and methods, and are not well established [49]. It has been suggested that for EQ-5D differences among health state utilities of at least 0.036 can be considered clinically important [50].…”

Early Physical Rehabilitation after Sentinel Lymph Node Biopsy in Breast Cancer: Is It Feasible and Safe?

“…A higher score indicates better functioning and more symptoms. A 5-point difference in quality of life scores is considered the minimum clinically significant difference [ 30 ].…”