The SF-36 physical and mental health factors were confirmed in cancer and HIV/AIDS patients

Background and 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. Conclusion: This paper demonstrated the value of Rasch residual factor analysis for understanding and enhancing interpretation of health. (c) 2006 Elsevier Inc. All rights reserved.