Defining score interpretation thresholds for clinical outcome assessments: a review of terminology and reporting...

The concept of 'score interpretation threshold' for understanding score differences of clinical outcome assessments (COAs) and terminology around this topic have evolved over several decades. Yet, considerable confusion regarding terminology remains, leading to potentially erroneous interpretation of COA results. This article sought to provide an updated overview of terminology and an assessment of trends to explore opportunities for harmonizing the field.

A targeted literature review was conducted for review articles published 2016-September 2024 discussing terminology related to COA score interpretation thresholds, followed by a review of guidance by regulatory and reimbursement/payer stakeholders for specific terminology in this context. A targeted review of original research articles that were aimed at deriving interpretation thresholds was undertaken, spanning a five-year period (2016- Apr 2021) to explore potential trends regarding use of terms, acronyms, and definitions.

As expected, vast heterogeneity in terminology and definitions was observed across review articles and regulatory/reimbursement/payer guidelines. Across 318 original research articles, 39 different terms were identified, with 'minimal clinically important difference' (MCID) most frequently used (mentioned in 163 articles), which was more than twice as often as the next term ('minimal important difference'; MID), mentioned in 76 articles, followed by 'minimal important change' (MIC), mentioned in 54 articles. Articles also showed great variation in how thresholds were defined, derived, and applied. Frequently, authors failed to provide sufficient details on methods and application, making it difficult to interpret derived thresholds.

COA score interpretation threshold terminology is far from harmonized. Evidence is insufficient to derive specific recommendations on which terms to use. Instead, we present minimum reporting standards for defining thresholds to ensure that they are comprehensible and reproducible, regardless of the specific terms and acronyms used.