The SF-36 physical and mental health factors were confirmed in cancer and HIV/AIDS patients.
OBJECTIVE
This study assesses the extent to which the RAND-36/SF-36 items measure physical and mental health (PH and MH), as implied by existing summary scoring systems.


METHODS
A total of 1,714 heterogeneous cancer and HIV/AIDS patients were recruited from five institutions. Of these, 56% were women; 81% Caucasians; and about 10% were from each of the major cancer types and HIV/AIDS.


RESULTS
Analyses of the SF-36 confirmed the two dimensions of health namely physical and mental. However, item fit statistics and residual factor analysis revealed that some items intended to represent the PH dimension fit better with the MH dimension.


CONCLUSIONS
This paper demonstrated the value of Rasch residual factor analysis for understanding and enhancing interpretation of health.
Chang
Chih-Hung
CH
Buehler Center on Aging, Institute for Healthcare Studies, Division of General Internal Medicine, and Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA. chchang@northwestern.edu
Wright
Benjamin D
BD
Cella
David
D
Hays
Ron D
RD
D000203:Activities of Daily Living; D000328:Adult; D000368:Aged; D001294:Attitude to Health; D005163:Factor Analysis, Statistical; D005260:Female; D015658:HIV Infections / Q000503:physiopathology / Q000523:psychology / Q000534:rehabilitation*; D006305:Health Status Indicators; D006801:Humans; D008297:Male; D008603:Mental Health; D008875:Middle Aged; D009369:Neoplasms / Q000503:physiopathology / Q000523:psychology / Q000534:rehabilitation*; D011594:Psychometrics; D011788:Quality of Life