Use of SF-36 and SF-12 health status measures: a quantitative comparison for groups versus individual patients.
BACKGROUND
The extent to which SF-12 scores reflect SF-36 scores has not been well studied.


OBJECTIVE
One purpose was to compare the sensitivity to change of the SF-36 Physical Function sub-score, and the Physical Component Summary Scores (PCS) of the SF-36 and SF-12 on patients with low back pain (LBP). A second purpose was to determine if the SF-12 could serve as a surrogate measure for the SF-36 when making decisions about individual patients.


METHODS
The sample consisted of 101 consecutive patients.


METHODS
SF-36 questionnaires were completed by patients at both initial and discharge examinations. SF-12 scores were calculated from the completed SF-36 questionnaires. Therapists' judgments of whether patients were judged to have returned to premorbid function served as the construct for meaningful clinical change.


METHODS
Receiver Operating Characteristic (ROC) curve analysis and repeated measures MANCOVA were used to assess sensitivity to change. Linear regression and 95% prediction bands described the extent to which SF-12 scores predict individual SF-36 scores.


RESULTS
No significant differences were found between the ROC curve areas for the Physical Function sub-scale, the PCS-36 and PCS-12. No significant differences were found for the comparison of change scores between PF-36, PCS-36 and PCS-12 scores.


CONCLUSIONS
The findings suggest that Physical Function sub-scores, SF-36 and SF-12 PCS scores are equally sensitive to change. SF-12 PCS scores do not adequately predict SF-36 PCS scores for individual patients. The PCS-12 should probably not be used to make judgments about the health status of individual patients with LBP.
Riddle
D L
DL
Department of Physical Therapy, School of Allied Health Professions, Medical College of Virgina, Virginia Commonwealth University, Richmond, VA 23298-0224, USA. driddle@hsc.vcu.edu
Lee
K T
KT
Stratford
P W
PW
D000203:Activities of Daily Living / Q000145:classification*; D000328:Adult; D000368:Aged; D003657:Decision Making; D005260:Female; D006305:Health Status Indicators; D006801:Humans; D016014:Linear Models; D017116:Low Back Pain / Q000175:diagnosis* / Q000534:rehabilitation*; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D010147:Pain Measurement / Q000379:methods*; D012372:ROC Curve; D011795:Surveys and Questionnaires