Determining the clinical importance of treatment benefits for interventions for painful orthopedic conditions

Abstract

The overarching goals of treatments for orthopedic conditions are generally to improve or restore function and alleviate pain. Results of clinical trials are generally used to determine whether a treatment is efficacious; however, a statistically significant improvement may not actually be clinically important, i.e., meaningful to the patient. To determine whether an intervention has produced clinically important benefits requires a two-step process: first, determining the magnitude of change considered clinically important for a particular measure in the relevant population and, second, applying this yardstick to a patient’s data to determine whether s/he has benefited from treatment. Several metrics have been devised to quantify clinically important differences, including the minimum clinically important difference (MCID) and clinically important difference (CID). Herein, we review the methods to generate the MCID and other metrics and their use and interpretation in clinical trials and practice. We particularly highlight the many pitfalls associated with the generation and utilization of these metrics that can impair their correct use. These pitfalls include the fact that different pain measures yield different MCIDs, that efficacy in clinical trials is impacted by various factors (population characteristics, trial design), that the MCID value is impacted by the method used to calculate it (anchor, distribution), by the type of anchor chosen and by the definition (threshold) of improvement. The MCID is also dependent on the population characteristics such as disease type and severity, sex, age, etc. For appropriate use, the MCID should be applied to changes in individual subjects, not to group changes. The MCID and CID are useful tools to define general guidelines to determine whether a treatment produces clinically meaningful effects. However, the many pitfalls associated with these metrics require a detailed understanding of the methods to calculate them and their context of use. Orthopedic surgeons that will use these metrics need to carefully understand them and be aware of their pitfalls.

Corticosteroid Injections Give Small and Transient Pain Relief in Rotator Cuff Tendinosis: A Meta-analysis

“…Despite that the MCID depends on the condition type, the severity, sex, and age, to our knowledge, the MCID of the VAS has not been studied for upper extremity problems. In musculoskeletal problems, however, the MCID has been shown to vary from 9 mm in low back pain to 37 mm in knee osteoarthritis [35]. Given that the MCID should be applied to changes in individual subjects, not to group changes, we were unable to determine how many of patients in the reviewed trials experienced a meaningful difference in their pain.…”

Statistics In Brief: Minimum Clinically Important Difference—Availability of Reliable Estimates

“…In studies using the ROC approach, two additional alternatives exist: studies that focus on maximum overall accuracy, and studies that ascertain whether 80% specificity had been achieved. Importantly, Katz et al [11] also warn that anchor-based approaches may be misleading in scenarios where a few patients show large benefits, but most show negligible changes.…”

“…Before the current work, a compendium of outcome scores was assembled by Katz et al [11], who reviewed painful orthopaedic conditions. They found, as we have, that there is a range of MCIDs for the same condition, and that some scores depend on the initial condition of the patient.…”

Women Demonstrate More Pain and Worse Function Before THA but Comparable Results 12 Months After Surgery

“…The MCID values reported in the literature refer to changes over time (mostly for improvement) within a group, usually in relation to some external criterion of change, ie, they reflect ''change'' rather than ''differences.'' In addition, the MCID depends on the characteristics of the population and the treatment used and should be used only for general guidance in interpreting individual, not group change [24]. Depending on the method used for calculation, the MCID values reported in the literature range from 6 to 29 for WOMAC and from 1 to 11 for OHS [2, 6-8, 13, 16, 36, 41, 44, 45]; if these values are used to interpret the clinical relevance of our findings (despite the previously mentioned caveats), the CIs of our baseline gender differences would include clinically important differences, whereas the differences at 12 months are highly unlikely to be clinically relevant.…”