Objective: To investigate the psychometric performance and clinical validity of the 36-Item Short Form (SF-36) health survey when completed by asymptomatic HIV-positive Italian patients and to compare their health profile with a representative sample of 2031 Italian citizens (the Italian norm).
Patients and methods: This was an observational, multicentre, cross-sectional survey. Microbiologists throughout Italy recruited asymptomatic HIV-positive individuals who were aged at least 18 years and aware of their infection. Investigators collected demographic, social, clinical and treatment data. Patients, classified into 2 clinical categories (A1 and A2) according to explicit pre-defined criteria, completed the SF-36 health survey in the context of a medical visit.
Results: Between April and July 1996, 46 microbiologists recruited 214 patients (201 evaluable). No inconsistent responses were observed in 96% of the sample. The usually recommended psychometric standards were satisfied, and the internal consistency reliability indices were always greater than 0.70. Weak to moderate associations were found between SF-36 health survey scores and physicians' estimates of patients' physical performance, while no significant associations were found with CD4+ counts. On average, HIV-positive patients reported lower scores than the Italian norm, and patients in category A2 showed lower scores than patients in A1. These differences were more relevant in scales describing role limitations, general health perception, and psychological well-being.
Conclusion: Our study showed that the SF-36 health survey maintained its psychometric properties in a sample of Italian asymptomatic HIV-positive patients and produced data that showed its validity and robustness in such a setting.