To determine the MIDs of pain intensity and disability outcomes in patients undergoing physical therapy treatment using the Global Rating of Change Scale (GRCS) as an anchor.
The data from this study came from a triple-blinded, placebo-controlled randomized controlled trial (RCT) which involved women with primary TMD symptoms. Participants were randomly assigned to either a motor control training using visual feedback (MCTF) or a placebo group (TENS). Both groups underwent an eight-week program, with two sessions per week for the first four weeks and one session per week for the subsequent four weeks. The main outcomes of this RCT were pain intensity measured with the Visual Analogue Scale (VAS) and neck disability measured with the Neck Disability Index (NDI) at baseline, two months, and six months post-randomization. This secondary analysis focused on these main outcomes at the end of the treatment. Participants were divided in responders and non-responders based on their response to the treatment, according to the GRCS. We used anchor-based methods (Change Difference (CD) and the Receiver Operating Characteristic curve) to estimate the MID of each of the outcomes of interest (e.g., VAS and NDI) using the GRCS as the anchor. Changes from baseline to end of treatment were calculated for each one of these outcomes for analysis to determine the MID values.
Eighty-seven women with an average age of 28.01 years were included in these analyses; 42 from the exercise group and 45 from placebo TENS group. No differences in baseline characteristics were observed between groups. Forty-one patients were considered responders to the treatments, and the remaining 41 were considered nonresponders based on the GRCS. MIDs calculated based on CD and ROC curves for changes before and after treatment on pain intensity were 9.9 points and 6.5 points, and for NDI, were 2.67 and 2.5 points, respectively.
As far as the author's knowledge, there is limited research on MID values of outcomes after physiotherapy treatment for patients with TMD. Pain intensity and neck disability are commonly used outcomes in patients with TMD, and thus, these MID values could potentially be used as guidance for both clinical practice and research when determining the clinical relevance of treatment effects in this specific population.
In the era of Evidence-Based Practice (EBP), it is crucial that research supports clinical practice and that clinical significance is evaluated. By providing minimal important differences (MIDs) of key outcomes in the field, clinicians can determine the usefulness and applicability of these outcomes in clinical settings. This information will strengthen the ability of practitioners in this field to determine the most effective interventions.
clinical significance
randomized controlled trial
