Minimal important change in physical function in trauma patients: a study using the short musculoskeletal function
M W de Graaf1, I H F Reininga2, E Heineman3
1Department of Trauma Surgery, University Medical Center Groningen, University of Groningen, PO Box 30 001, 9700 RB, Groningen, The Netherlands. m.w.de.graaf@umcg.nl.
Purpose:
The Short Musculoskeletal Function Assessment (SMFA) questionnaire can be used to evaluate physical functioning in patients with traumatic injuries. It is not known what change in score reflects a meaningful change to patients. The aim was to determine minimal important change (MIC) values of the subscales (0-100) of the Dutch SMFA-NL in a sample of patients with a broad range of injuries.
Methods:
Patients between 18 and 65 years of age completed the SMFA-NL and the Global Rating of Effect (GRE) questions at 6-week and 12-month post-injury. Anchor-based MIC values were calculated using univariable logistic regression analyses.
Results:
A total of 225 patients were included (response rate 67%). The MIC value of the Upper Extremity Dysfunction (UED) subscale was 8 points, with a misclassification rate of 43%. The Lower Extremity Dysfunction subscale MIC value was 14 points, with a misclassification rate of 29%. The MIC value of the Problems with Daily Activities subscale was 25 points, with a misclassification rate of 33%. The MIC value of the Mental and Emotional Problems (MEP) subscale was 7 points, with a misclassification rate 37%.
Conclusion:
MIC values of the SMFA-NL were determined. The MIC values aid interpreting whether a change in physical functioning can be considered clinically important. Due to the considerable rates of misclassification, the MIC values of the UED and MEP subscales should be used with caution.
