Calculation of the minimum clinically important difference (MCID) using different methodologies: case study and practical guide.

INTRODUCTION: Establishing thresholds of change that are actually meaningful for the patient in an outcome measurement instrument is paramount. This concept is called the minimum clinically important difference (MCID). We summarize available MCID calculation methods relevant to spine surgery, and outline key considerations, followed by a step-by-step working example of how MCID can be calculated, using publicly available data, to enable the readers to follow the calculations themselves. METHODS: Thirteen MCID calculations methods were summarized, including anchor-based methods, distribution-based methods, Reliable Change Index, 30% Reduction from Baseline, Social Comparison Approach and the Delphi method. All methods, except the latter two, were used to calculate MCID for improvement of Zurich Claudication Questionnaire (ZCQ) Symptom Severity of patients with lumbar spinal stenosis. Numeric Rating Scale for Leg Pain and Japanese Orthopaedic Association Back Pain Evaluation Questionnaire Walking Ability domain were used as anchors. RESULTS: The MCID for improvement of ZCQ Symptom Severity ranged from 0.8 to 5.1. On average, distribution-based methods yielded lower MCID values, than anchor-based methods. The percentage of patients who achieved the calculated MCID threshold ranged from 9.5% to 61.9%. CONCLUSIONS: MCID calculations are encouraged in spinal research to evaluate treatment success. Anchor-based methods, relying on scales assessing patient preferences, continue to be the "gold-standard" with receiver operating characteristic curve approach being optimal. In their absence, the minimum detectable change approach is acceptable. The provided explanation and step-by-step example of MCID calculations with statistical code and publicly available data can act as guidance in planning future MCID calculation studies.

Determining the minimally clinically important difference for the pediatric liver transplant quality of life questionnaire.

PURPOSE: The Pediatric Liver Transplant Quality of Life (PeLTQL) questionnaire is a disease-specific patient reported outcome measure for pediatric liver transplant (LT) recipients. To-date, threshold values above which a change in PeLTQL score is considered meaningful to patients are unavailable. This study proposes the first values for the minimally clinically important difference (MCID) for the PeLTQL. METHODS: In this retrospective cohort study, anchor and distribution-based methods were used to estimate the MCID for the PeLTQL. Questionnaires completed between March 2013, and July 2022 were included if data from two sequential visits were available. An internal anchor question was used for anchor-based determination of the MCID. A final MCID estimate was ascertained from triangulation of all methods. RESULTS: PeLTQL data from 65 LT recipients (26 [40%] male, 17 [42%] biliary atresia, median age at LT 3.08 years [interquartile range 0.99-7.30]), and their caregivers were included for analysis. Median patient age at time of baseline PeLTQL completion was 13.84 (10.90-15.86) years. The MCID for self-PeLTQL total scores ranged from 4.53 to 8.46, and from 4.47 to 8.85 for proxy responses. By triangulation, the MCID of the PeLTQL total score was 6.45 and 6.78 for self and proxy responses respectively. CONCLUSION: A change in PeLTQL score of 6.5 or more points suggests a change in health status that is meaningful to the patient, providing the clinical team an opportunity to engage the patient's voice in reassessing current health status and management strategies.

Minimal clinically important differences in health-related quality of life after treatment with direct-acting antivirals for chronic hepatitis C: ANRS CO22 HEPATHER cohort (PROQOL-HCV).

PURPOSE: Patient Reported Outcomes Quality of Life survey for HCV (PROQOL-HCV) is a specific tool developed to assess health-related quality of life (HRQoL) in patients with chronic hepatitis C receiving direct-acting antivirals (DAA). Thresholds for clinically meaningful changes in PROQOL-HCV scores should be documented to improve the tool's use in clinical practice. This study aimed to estimate the minimal clinically important differences (MCIDs) in PROQOL-HCV scores before and after HCV cure by DAA among participants in the prospective cohort ANRS-CO22 HEPATHER. METHODS: Data from 460 chronic HCV patients were collected at DAA initiation (baseline) and 24 weeks after treatment end. MCIDs were estimated for the six HRQoL dimensions (Physical Health (PH), Emotional Health (EH), Future Uncertainty (FU), Intimate Relationships (IR), Social Health (SH), and Cognitive Functioning (CF)) using two approaches: anchor-based and score distribution-based. Each MCID was estimated for improvement/deterioration both globally and separately for patients with a baseline PRQoL-HCV score ≤ 50 (group1) and patients with a baseline PRQoL-HCV score > 50 (group2). RESULTS: The pooled MCIDs for improvement/deterioration globally, in group1, and in group2, respectively, were as follows: 8.8/- 7.6, 9.7/- 9.5, and 6.0/- 6.9 for PH; 7.1/- 4.6, 7.7/- 9.6, and 6.6/- 6.7 for EH; 6.7/- 6.7, 8.2/- 8.2, and 6.0/- 6.0 for FU; 7.0/- 7.0, 5.4/- 5.4, and 6.2/- 6.2 for IR; 7.7/- 7.7, 8.6/- 8.6, and 6.5/- 6.5 for SH; 7.3/- 5.6, 9.1/- 8.0, and 6.5/- 6.3 for CF. CONCLUSIONS: The overall MCID for the PROQOL-HCV scores ranged from 6.7 to 8.8 for improvement and from - 7.7 to - 4.6 for deterioration. The effect of DAA on PROQOL-HCV scores seemed particularly beneficial for patients with lower baseline scores. This subgroup could be motivated to take DAA if they are informed of the benefits for their HRQoL.

Assessing Clinically Important Differences During Rehabilitation for Stroke: A Pilot Study Evaluating Anchor and Distribution Derived Estimates of Physical Function Change in Classically Summed and Rasch Models of Section GG of the Inpatient Rehabilitation Facility Patient Assessment Instrument.

OBJECTIVE: To determine clinically important differences (CIDs) on Section GG physical functioning scores on the Centers for Medicare and Medicaid Services (CMS) Inpatient Rehabilitation Facility Assessment Instrument (IRF-PAI) for patients with stroke, using anchor and distribution-based approaches. DESIGN: Pilot prospective observational cohort study. SETTING: Inpatient rehabilitation facility. PARTICIPANTS: Patients with stroke (N=208). INTERVENTIONS: Physicians assessed improvements during rehabilitation using the modified Rankin scale (mRS). Improvements (≥1 point) on the mRS were used as the anchor for establishing CIDs. MAIN OUTCOME MEASURES: Classically summed and Rasch transformed Section GG change scores associated with clinically important improvements on the mRS. RESULTS: A total of 166 patients (79.8%) improved ≥1 point on the mRS. Change scores of 27, 9, and 16 on Section GG total physical functioning (self-care + mobility), self-care, and mobility/walk scales, respectively, had high sensitivity (0.82-0.85) but low specificity (0.52-0.69) in identifying patients improving on the mRS. Positive predictive values ranged from 0.87 to 0.91, and negative predictive values ranged from 0.42 to 0.52. Total physical functioning and selfcare anchor-derived change scores were similar to the reliable change index (RCI [2.77 × SEM]), calculated as 28 and 10 points, respectively, whereas anchor-derived mobility/walk scale change scores were equivalent to 1.96 × SEM. Exploratory Rasch modeling identified 3 Section GG subscales (R-Self-Care, R-Mobility, and R-Walking). Improvements on the R-Walking subscale were most correlated with mRS improvements (ρ=-0.47); however, accuracy of CID estimates was not improved. CONCLUSIONS: Cut-off scores obtained using the mRS anchor aligned with more robust estimates of change, as estimated by distribution-based measures. While patients achieving anchor-derived cut-offs have a high probability of mRS improvement, change scores may fail to detect clinically meaningful improvements at these same thresholds. Alternative criteria for determining MCID/CIDs, should be explored. Rasch models require further validation.

Minimal important difference in postoperative morphine consumption after hip and knee arthroplasty using nausea, vomiting, sedation and dizziness as anchors.

BACKGROUND: Morphine-sparing effects are often used to evaluate non-opioid analgesic interventions. The exact effect that would warrant the implementation of these interventions in clinical practice (a minimally important difference) remains unclear. We aimed to determine this with anchor-based methods. METHODS: This was a post hoc analysis of three studies investigating pain management after hip or knee arthroplasty (PANSAID [NCT02571361], DEX-2-TKA [NCT03506789] and Pain Map [NCT02340052]). The overall population was median aged 70, median ASA 2, 54% female. We examined the correlation between 0 and 24 h postoperative iv morphine equivalent consumption and the severity of nausea, vomiting, sedation and dizziness. The anchor was different severity degrees of these opioid-related adverse events. The primary outcome was the difference in morphine consumption between patients experiencing no versus only mild events. Secondary outcomes included the difference in morphine consumption between patients with mild versus moderate and moderate versus severe events. We used Hodges-Lehmann median differences, exact Wilcoxon-Mann-Whitney tests and quantile regression. RESULTS: The difference in iv morphine consumption was 6 mg (95% confidence interval: 4-8) between patients with no versus only mild events, 5 mg (2-8) between patients with mild versus moderate events and 0 mg (-4 to 4) between patients with moderate versus severe events. CONCLUSIONS: In populations comparable to this post-hoc analysis (orthopaedic surgery, median age 70 and ASA 2), we suggest a minimally important difference of 5 mg for 0-24 h postoperative iv morphine consumption.

Minimal Clinically Important Difference (MCID) in Patient-Reported Outcome Measures for Neurological Conditions: Review of Concept and Methods.

The concept of the minimal clinically important difference (MCID) emerged from the recognition that statistical significance alone is not enough to determine the clinical relevance of treatment effects in clinical research. In many cases, statistically significant changes in outcomes may not be meaningful to patients or may not result in any tangible improvements in their health. This has led to a growing emphasis on the importance of measuring patient-reported outcome measures (PROMs) in clinical trials and other research studies, in order to capture the patient perspective on treatment effectiveness. MCID is defined as the smallest change in scores that is considered meaningful or important to patients. MCID is particularly important in fields such as neurology, where many of the outcomes of interest are subjective or based on patient-reported symptoms. This review discusses the challenges associated with interpreting outcomes of clinical trials based solely on statistical significance, highlighting the importance of considering clinical relevance and patient perception of change. There are two main approaches to estimating MCID: anchor-based and distribution-based. Anchor-based approaches compare change scores using an external anchor, while distribution-based approaches estimate MCID values based on statistical characteristics of scores within a sample. MCID is dynamic and context-specific, and there is no single 'gold standard' method for estimating it. A range of MCID thresholds should be defined using multiple methods for a disease under targeted intervention, rather than relying on a single absolute value. The use of MCID thresholds can be an important tool for researchers, neurophysicians and patients in evaluating the effectiveness of treatments and interventions, and in making informed decisions about care.

Exploration of the methods of establishing the minimum clinical important difference based on anchors and their applications in the quality of life measurement scale QLICP-BR (V2.0) for breast cancer.

Objective: The measurement of the quality of life (QOL) in patients with breast cancer can evaluate the therapeutic effects of medical treatments and help to provide reference for clinical decisions. The minimum clinically important difference (MCID) can be better used in clinical interpretation than the traditional statistical significance. Based on the anchors, a variety of ways including traditional and updated anchor-based methods were used to explore most suitable MCID, so that to find better interpretation on scores of the scale QLICP-BR(V2.0) (Quality of Life Instruments for Cancer Patients-Breast cancer). Methods: According to the investigation data of breast cancer patients before and after treatment, the most relevant indicators in various domains of QLICP-BR (V2.0) was found as an anchor to statistically analyze the value of MCID, and three analysis methods of anchors were used: Traditional anchor-based method, ROC curve method, multiple linear regression model analysis. Anchors are divided into four standards according to the degree of change in the treatment effect: one grade difference (Standard A), at least one grade difference (Standard B), one grade better (Standard C), better (Standard D). The final MCID value is selected from different statistical methods and classification standards that are most suitable for clinicians to use. Results: Using Q29 of the EORTC QLQ-C30 as an anchor has the highest correlation with each domain of QLICP. The order of magnitude of MCID values among the four standard groups is: standard A< Standard C< Standard B< Standard D. The MCID value obtained by the ROC curve method is the most stable and is least affected by the sample size, and the MCID value obtained by the multiple linear regression model is the least. After comparisons and discussions, Standard C in the multiple linear regression model is used to determine the final MCID, which is the closest to other methods. After integer the MCID values of Physical domain (PHD), Psychological domain (PSD), Social domain (SOD), Common symptoms and side effect domain (SSD), Core/general module (CGD), Specific domain (SPD), Total score(TOT) can be taken as 15,10, 10, 11, 10, 9 and 9, respectively. Conclusion: In the evaluation of the QOL of breast cancer patients, although the results of MCID values produced by different methods are different, the results are relatively close. The anchor-based methods make the results of MCID more clinically interpretable by introducing clinical variables, and clinicians and researchers can choose the appropriate method according to the research purpose.

Serious reporting deficiencies exist in minimal important difference studies: current state and suggestions for improvement.

BACKGROUND AND OBJECTIVES: To evaluate reporting of minimal important difference (MID) estimates using anchor-based methods for patient-reported outcome measures (PROMs), and the association with reporting deficiencies on their credibility. METHODS: Systematic survey of primary studies empirically estimating MIDs. We searched Medline, EMBASE, PsycINFO, and the Patient-Reported Outcome and Quality of Life Instruments Database until October 2018. We evaluated study reporting, focusing on participants' demographics, intervention(s), characteristics of PROMs and anchors, and MID estimation method(s). We assessed the impact of reporting issues on credibility of MID estimates. RESULTS: In 585 studies reporting on 5,324 MID estimates for 526 distinct PROMs, authors frequently failed to adequately report key characteristics of PROMs and MIDs, including minimum and maximum values of PROM scale, measure of variability accompanying the MID estimate and number of participants included in the MID calculation. Across MID estimates (n = 5,324), the most serious reporting issues impacting credibility included infrequent reporting of the correlation between the anchor and PROM (66%), inadequate details to judge precision of MID point estimate (13%), and insufficient information about the threshold used to ascertain MIDs (16%). CONCLUSION: Serious issues of incomplete reporting in the MID literature threaten the optimal use of MID estimates to inform the magnitude of effects of interventions on PROMs.

Establishing minimal clinically important difference for the UCLA and ASES scores after rotator cuff repair.

BACKGROUND/HYPOTHESIS: Minimal clinically important difference (MCID) is a vital tool in the analysis of clinical results. It allows the determination of clinical relevance of statistical data. Our hypothesis was that specific differences between preoperative and postoperative scores would be able to accurately predict patient perception of improvement and satisfaction as reflected by anchor and distribution-based questions. METHODS: Retrospective cohort with patients that underwent rotator cuff repair. We evaluated the University of California at Los Angeles Shoulder Rating Scale (UCLA) and the American Shoulder and Elbow Surgeons Assessment Form (ASES) before and 12-months after surgery. Anchor-based, distribution-based and minimum detectable change (MDC) approaches were utilized. RESULTS: We evaluated 289 shoulders. The MCID for the UCLA scale was 4.5 points using the anchor method, 2.5 by the distribution method and 3.6 by MDC. Patients with a baseline score>20 presented a lower MCID (1.5, 1.1 and 1.7, respectively). For the ASES score, the MCID was 6.1 by the anchor method, 10.5 based on the distribution method and 26.3 by MDC. In the group of patients above the 60 point cutoff, the obtained values were 2.4, 4.9 and 13.6, respectively. CONCLUSION: The mean MCID value for the UCLA shoulder score is 3.5 points, ranging from 2.5 points (distribution method) to 4.5 points (anchor method). The mean MCID value for the ASES score was 15.2 points, ranging from 6.1 (anchor method) to 26.3 (MDC). Patients groups presenting with higher preoperative scores showed lower MCID values. This fact needs to be considered in postoperative comparisons between treatment groups. LEVEL OF EVIDENCE: Basic Science Study, Validation of Outcomes Instruments/Classification Systems.

A Patient-Centered Evaluation of Meaningful Change on the 32-Item Motor Function Measure in Spinal Muscular Atrophy Using Qualitative and Quantitative Data.

The 32-item Motor Function Measure (MFM32) is an assessment of motor function used to evaluate fine and gross motor ability in patients with neuromuscular disorders, including spinal muscular atrophy (SMA). Reliability and validity of the MFM32 have been documented in individuals with SMA. Through semi-structured qualitative interviews (N = 40) and an online survey in eight countries (N = 217) with individuals with Types 2 and 3 SMA aged 2-59 years old and caregivers, the meaning of changes on a patient-friendly version of the MFM32 was explored. In an independent analysis of clinical trial data, anchor- and distribution-based analyses were conducted in a sample of individuals with Type 2 and non-ambulant Type 3 SMA to estimate patient-centered quantitative MFM32 meaningful change thresholds. The results from this study demonstrate that, based on patient and caregiver insights, maintaining functional ability as assessed by a patient-friendly version of the MFM32 is an important outcome. Quantitative analyses using multiple anchors (median age range of 5-8 years old across anchor groups) indicated that an ~3-point improvement in MFM32 total score represents meaningful change at the individual patient level. Overall, the qualitative and quantitative findings from this study support the importance of examining a range of meaningful change thresholds on the MFM32 including ≥0 points change reflecting stabilization or improvement and ≥3 points change reflecting a higher threshold of improvement. Future research is needed to explore quantitative differences in meaningful change on the MFM32 based on age and functional subgroups.

Establishing anchor-based minimally important differences (MID) with the EORTC quality-of-life measures: a meta-analysis protocol.

INTRODUCTION: As patient assessment of health-related quality of life (HRQOL) in cancer clinical trials has increased over the years, so has the need to attach meaningful interpretations to differences in HRQOL scores between groups and changes within groups. Determining what represents a minimally important difference (MID) in HRQOL scores is useful to clinicians, patients and researchers, and can be used as a benchmark for assessing the success of a healthcare intervention. Our objective is to provide an evidence-based protocol to determine MIDs for the European Organisation for Research and Treatment for Cancer Quality of life Questionnaire core 30 (EORTC QLQ-C30). We will mainly focus on MID estimation for group-level comparisons. Responder thresholds for individual-level change will also be estimated. METHODS AND ANALYSIS: Data will be derived from published phase II and III EORTC trials that used the QLQ-C30 instrument, covering several cancer sites. We will use individual patient data to estimate MIDs for different cancer sites separately. Focus is on anchor-based methods. Anchors will be selected per disease site from available data. A disease-oriented and methodological panel will provide independent guidance on anchor selection. We aim to construct multiple clinical anchors per QLQ-C30 scale and also to compare with several anchor-based methods. The effects of covariates, for example, gender, age, disease stage and so on, will also be investigated. We will examine how our estimated MIDs compare with previously published guidelines, hence further contributing to robust MID guidelines for the EORTC QLQ-C30. ETHICS AND DISSEMINATION: All patient data originate from completed clinical trials with mandatory written informed consent, approved by local ethical committees. Our findings will be presented at scientific conferences, disseminated via peer-reviewed publications and also compiled in a MID 'blue book' which will be made available online on the EORTC Quality of Life Group website as a free guideline document.

Domain-specific transition questions demonstrated higher validity than global transition questions as anchors for clinically important improvement.

OBJECTIVES: Estimates of minimal clinically important differences in health measures may be affected by the anchor used. We examined if domain-specific transition questions had higher construct validity than global health transition questions as anchors for measures in a given domain. STUDY DESIGN AND SETTING: In a prospective study of 249 patients with rheumatoid arthritis, we examined changes in pain, physical function, joint swelling, stiffness, fatigue, and depression with treatment. We related these changes to a domain-specific transition question, global arthritis transition question, and the Short Form-36 (SF-36) health transition item. RESULTS: Changes in all six clinical measures were more highly correlated with the domain-specific transition questions than with the global arthritis question and SF-36 transition question. Discrimination between patients who improved or not was also better using domain-specific questions. Estimates of minimal clinically important improvement (MCII) differed with the anchor when these were based on mean changes. MCII estimates from receiver operating characteristic curve analysis were not influenced by the choice of anchor when anchors had high agreement. CONCLUSION: Domain-specific transition questions had higher construct validity as anchors for determining clinically important differences in health measures focused on a single domain than either global disease or general health transition questions.

Minimal important changes in the Constant-Murley score in patients with subacromial pain.

OBJECTIVE: The purpose of this study was to determine the minimal important change (MIC) of improvement in the Constant-Murley score in patients with long-standing subacromial pain and in subgroups of patients with subacromial pain with and without rotator cuff ruptures. METHOD: The MIC was estimated by the anchor-based MIC distribution method, which integrates an anchor- and distribution-based approach: the optimal cutoff point of the receiver operating characteristic curve (MICROC) and the 95% limit cutoff point (MIC95% limit). The study population consisted of 93 patients included in a randomized clinical trial evaluating the effect of a specific exercise strategy. RESULTS: The MICROC was found at a mean change of 17 points in the Constant-Murley score, which corresponds to a sensitivity of 91% and a specificity of 79%. The MIC95% limit was found at a mean change of 24 points. In the subgroup analysis, the MICROC was found at a mean change of 19 points and the MIC95% limit at 18 points in patients with an intact rotator cuff. In patients with rotator cuff ruptures, the MICROC was found at a mean change of 15 points and the MIC95% limit at 30 points. CONCLUSION: The Constant-Murley score is able to detect the MIC in individual patients with long-standing subacromial pain when the rotator cuff is intact. The estimated MIC values could be used as an indication for relevant changes in the Constant-Murley score in clinical practice and guide the clinician in how to interpret the results of specific treatments.

Health-related quality of life as an outcome variable in Parkinson's disease.

In the past three decades, health-related quality of life (HRQoL) has become an outcome variable in Parkinson's disease clinical trials. This review considers the measuring tools that have been developed, suitability of data reporting, complexity of outcome interpretation, and clinical application to provide evidence regarding available therapeutic interventions to date. In the introduction, different terms regarding quality of life are clearly defined. The methodology section offers an overview of generic, disease specific, and recommended HRQoL scales in Parkinson's disease and the most important psychometric attributes a scale should meet. The interpretation of HRQoL outcomes is complex and not intuitive. Thus, appropriate reporting of data is crucial in order to calculate relative change, a result that facilitates understanding to what extent an intervention is beneficial. The concept of minimally important change/difference is explained as well as the different approaches to its calculation (anchor-based and distribution-based methods). In the results section, a brief overview of the impact on HRQoL of currently available treatments in Parkinson's disease is provided. Special emphasis is given to data assessment, highlighting reports that helped understanding of the clinical significance of the intervention and therefore aided in making therapeutic decisions. The discussion section emphasizes the need for more clinical trials with HRQoL as a primary outcome and standardized reporting in order to further our understanding of the complexity of treatment effects and make evidence-based clinical decisions regarding HRQoL in patients with Parkinson's disease.