Reliable change and minimum important difference (MID) proportions facilitated group responsiveness comparisons using individual threshold criteria.
OBJECTIVE
This study contrasted the use of responsiveness indices at the group level vs. individual patient level.


METHODS
We followed a cohort of 211 patients (50% male; mean age 47.5 years; SD 14) with musculoskeletal upper extremity problems for a total of 3 months. Outcome measures included the Disabilities of the Arm, Shoulder, and Hand (DASH) questionnaire, Shoulder Pain and Disability Index (SPADI), Patient-Rated Wrist Evaluation (PRWE), and the Medical Outcomes Study 12-Item Short-Form Health Survey (SF-12). We calculated confidence intervals on various group-level responsiveness statistics based on effect size and correlation with global change. The proportion of patients exceeding the minimum detectable change (or reliable change proportion) and minimum important difference (MID proportion) were included as indices applicable to the individual patient.


RESULTS
For the DASH, effect size ranged from 1.06 to 1.67 for various patient subgroups, and the reliable change and MID proportions indicated that 50%-70% of individuals exhibited change based on individual change scores. Only the SRM and reliable change proportion indicated differences among the outcome measures used in this study.


CONCLUSIONS
The reliable change and MID proportions have an intuitive interpretation and facilitate quantitative responsiveness comparisons among outcome measures based on individual patient criteria.
Schmitt
John S
JS
Department of Physical Medicine and Rehabilitation, School of Medicine, University of Minnesota, Mayo Mail Code 388, Minneapolis, MN 55455, USA.
Di Fabio
Richard P
RP
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004185:Disability Evaluation; D005260:Female; D005500:Follow-Up Studies; D006305:Health Status Indicators; D006801:Humans; D008297:Male; D008875:Middle Aged; D026741:Physical Therapy Modalities; D015203:Reproducibility of Results; D000070599:Shoulder Injuries; D012785:Shoulder Joint / Q000503:physiopathology; D011795:Surveys and Questionnaires; D016896:Treatment Outcome; D014954:Wrist Injuries / Q000503:physiopathology / Q000534:rehabilitation*; D014955:Wrist Joint / Q000503:physiopathology