Discordance Abounds in Minimum Clinically Important Differences in THA: A Systematic Review

Abstract

BackgroundThe minimum clinically important difference (MCID) is intended to detect a change in a patient-reported outcome measure (PROM) large enough for a patient to appreciate. Their growing use in orthopaedic research stems from the necessity to identify a metric, other than the p value, to better assess the effect size of an outcome. Yet, given that MCIDs are population-specific and that there are multiple calculation methods, there is concern about inconsistencies. Given the increasing use of MCIDs in total hip arthroplasty (THA) research, a systematic review of calculated MCID values and their respective ranges, as well as an assessment of their applications, is important to guide and encourage their use as a critical measure of effect size in THA outcomes research.Questions/purposesWe systematically reviewed MCID calculations and reporting in current THA research to answer the following: (1) What are the most-reported PROM MCIDs in THA, and what is their range of values? (2) What proportion of studies report anchor-based versus distribution-based MCID values? (3) What are the most common methods by which anchor-based MCID values are derived? (4) What are the most common derivation methods for distribution-based MCID values? (5) How do the reported medians and corresponding ranges compare between calculation methods for each PROM?MethodsThe EMBASE, MEDLINE, and PubMed databases were systematically reviewed from inception through March 2022 for THA studies reporting an MCID value for any PROMs. Two independent authors reviewed articles for inclusion. All articles calculating new PROM MCID scores after primary THA were included for data extraction and analysis. MCID values for each PROM, MCID calculation method, number of patients, and study demographics were extracted from each article. In total, 30 articles were included. There were 45 unique PROMs for which 242 MCIDs were reported. These studies had a total of 1,000,874 patients with a median age of 64 years and median BMI of 28.7 kg/m2. Women made up 55% of patients in the total study population, and the median follow-up period was 12 months (range 0 to 77 months). The overall risk of bias was assessed as moderate using the modified Methodological Index for Nonrandomized Studies criteria for comparative studies (the mean score for comparative papers in this review was 18 of 24, with higher scores representing better study quality) and noncomparative studies (for these, the mean score was 10 of a possible 16 points, with higher scores representing higher study quality). Calculated values were classified as anchor-based, distribution-based, or not reported. MCID values for each PROM, MCID calculation method, number of patients, and study demographics were extracted from each study. Anchor-based and distribution-based MCIDs were compared for each unique PROM using a Wilcoxon rank sum test, given the non-normal distribution of values.ResultsThe Oxford Hip Score (OHS) and the Hip Injury and Osteoarthritis Score (HOOS) Pain and Quality of Life subscore M...

Letter to the Editor: There are Considerable Inconsistencies Among Minimum Clinically Important Differences in TKA: A Systematic Review

“…The investigators summarized evidence reporting minimum clinically important difference (MCID) estimates for knee and hip arthroplasty patient-reported outcome measures (PROMs). The titles of these papers emphasized that "discordance abounds" [2] and that there were "considerable inconsistencies" [3] in MCID estimates. We agree with this message of substantial MCID variability, a finding reported by others [8,10].…”

“…We were struck by the conflicting messages of two recently published systematic reviews by Deckey and colleagues [2,3]. The investigators summarized evidence reporting minimum clinically important difference (MCID) estimates for knee and hip arthroplasty patient-reported outcome measures (PROMs).…”

Reply to the Letter to the Editor: There are Considerable Inconsistencies Among Minimum Clinically Important Differences in TKA: A Systematic Review

“…We thank Dr. Riddle and Dr. Dumenci for their insightful response [7] to our systematic reviews about the use of minimum clinically important differences (MCID) for patient-reported outcome measures (PROMs) after hip and knee arthroplasty [3,4]. Much of their response focuses on inherent problems with the PROMS that have been commonly used in orthopaedic surgery, the limitations of MCIDs, as well as potential alternatives for determining meaningful changes.…”

CORR Insights®: Discordance Abounds in Minimum Clinically Important Differences in THA: A Systematic Review

“…The authors of this study in Clinical Orthopaedics and Related Research ® [2] conducted a systematic review of MCIDs reported in THA studies. This well-conducted methodologic review identified 242 eligible THA studies that calculated an MCID for any patient-reported outcome measure (PROM).…”

“…The authors noted that anchor-based MCIDs were larger than distribution-based MCIDs in all PROMs for which there was a direct comparison between the two approaches, indicating that the distribution-based method may underestimate the MCID. I suggest that readers of clinical research "bookmark" this CORR study [2] and keep it handy.…”