Importance of minimal clinically important difference in medical research and guideline development

Abstract

P-values have posed various challenges in conducting and interpreting medical research. In an endeavor to establish more objective criteria for assessing outcomes in medical care, statistical methods have been utilized to analyze clinical trial results, often leading to a perceived dichotomy: trial outcomes are categorized as either positive or negative based on a p-value. Unfortunately, clinicians began to overly rely on the statistical significance of studies, misinterpreting their findings as clinically meaningful. Recognizing the detrimental effects of p-values, the American Statistical Association advised against their use in scientific publications (1). Instead, emphasis should be placed on the magnitude of difference between intervention and control groups. Prior to conducting a study, and in assessing the results of a body of evidence it is essential to estimate the minimum size of the difference that would be clinically significant. The smallest magnitude of benefit that patients would deem as clinically important is the minimal clinically important difference (MCID) (2). The MCID encapsulates a patient-centered approach, encompassing both the degree of improvement and the value patients attribute to this change.