Responsiveness of the shoulder pain and disability index in patients with adhesive capsulitis.
BACKGROUND
Instruments designed to measure the subjective impact of painful shoulder conditions have become essential in shoulder research. The Shoulder Pain and Disability Index (SPADI) is one of the most extensively used scales of this type. The objective of this study was to investigate reproducibility and responsiveness of the SPADI in patients with adhesive capsulitis.


METHODS
SPADI test-retest reproducibility was estimated by the "intraclass correlation coefficient" (ICC) and the "smallest detectable difference" (SDD). Responsiveness was assessed by exploring baseline and follow-up data recorded in a recently reported clinical trial regarding hydrodilatation and corticosteroid injections in 76 patients with adhesive capsulitis. "Standardized response mean" (SRM) and "reliable change proportion" (RCP) for SPADI were compared with corresponding figures for shoulder range-of-motion (ROM). The relationship between SPADI and ROM change scores was investigated through correlation and linear regression analyses.


RESULTS
Results for test-retest reproducibility indicated a smallest detectable difference of 17 points on the 0-100 scale, and an intraclass correlation coefficient of 0.89. The SPADI was generally more responsive than ROM. Weak to moderately strong associations were identified between SPADI and ROM change scores. According to the regression model, the three variables baseline SPADI, baseline active ROM and change in active ROM together explained 60% of the variance in SPADI improvement.


CONCLUSIONS
This study supports the use of SPADI as an outcome measure in similar settings.
Tveitå
Einar Kristian
EK
Department of Physical Medicine and Rehabilitation, Ullevål University Hospital, University of Oslo, Oslo, Norway. e.k.tveita@medisin.uio.no
Ekeberg
Ole Marius
OM
Juel
Niels Gunnar
NG
Bautz-Holter
Erik
E
D000305:Adrenal Cortex Hormones / Q000627:therapeutic use; D002062:Bursitis / Q000175:diagnosis* / Q000453:epidemiology / Q000628:therapy; D015897:Comorbidity; D004185:Disability Evaluation; D018450:Disease Progression; D005500:Follow-Up Studies; D006801:Humans; D017063:Outcome Assessment, Health Care / Q000379:methods; D010147:Pain Measurement / Q000379:methods*; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D012785:Shoulder Joint / Q000473:pathology / Q000503:physiopathology; D020069:Shoulder Pain / Q000175:diagnosis* / Q000453:epidemiology / Q000628:therapy; D011795:Surveys and Questionnaires; D016896:Treatment Outcome
D000305:Adrenal Cortex Hormones