Objective: While health-related quality of life (HRQOL) is increasingly being used as an outcome in clinical trials, it is unknown whether HRQOL assessments are influenced by the method of administration. Within the context of a randomized, controlled trial evaluating a pharmacist intervention for elderly outpatients prescribed at least five medications, we compared telephone and face-to-face administration of the SF-36, a widely used HRQOL measure.
Design: Survey.
Setting: General Medicine Clinic, Veterans Affairs Medical Center.
Patients: At entry, participants in the randomized trial received continuous care from a general medicine clinic physician, were > or = 65 years of age, and were prescribed > or = 5 regularly scheduled medications. Patients were excluded if they were cognitively impaired and had no caregiver available to participate in the study as a proxy or if they resided in a nursing home.
Measurements: Subjects completed the SF-36 by telephone at closeout and face-to-face at clinic visits within 1 month (mean = 16.7 days).
Main results: Telephone administration required significantly less time than face-to-face interviews (10.2 vs 14.0 minutes, P < 0.001). Although systematic differences between modes of administration were generally small, there were substantial nonsystematic discrepancies for all eight SF-36 scales (mean absolute difference scores ranged from 10.8 to 30.1). Discrepancies were greatest for emotional role functioning, physical role functioning, social functioning, and bodily pain; these four scales also demonstrated low to moderate correlations (.33 to .58).
Conclusions: The two modes of administration may not produce interchangeable results. Researchers should be cautious when mixing modes of administration to elderly patients.