THE RELIABILITY AND VALIDITY OF THE GERIATRIC DEPRESSION RATING-SCALEADMINISTERED BY TELEPHONE

OBJECTIVE: To evaluate prospectively the reliability and validity of t he Geriatric Depression Scale administered by telephone (T-GDS) in pat ients undergoing outpatient comprehensive geriatric assessment. SUBJEC TS: A total of 101 geriatric patients were evaluated in a 1-year perio d at the outpatient Geriatric Assessment Center of the University of N ebraska Medical Center. METHODS: The 30-item GDS was completed by all patients on three occasions: by telephone several days before their as sessment, face-to-face during their assessment visit, and several days later, again by phone. During their assessment, all patients were eva luated by one of three geriatric psychiatrists who were blind to all G DS results. The test-retest reliability of the T-GDS was measured by c omparing the results of the two phone interviews. The construct validi ty of the T-GDS was estimated by comparing the results of the initial T-GDS to the GDS obtained during the comprehensive assessment. The cri terion validity of the T-GDS was estimated by comparing the results of the T-GDS with the clinical diagnosis of depression assigned by the p sychiatrists. RESULTS: The individual items of the initial T-GDS showe d substantial concordance with the second T-GDS (kappa range 0.35 - 0. 7, mean = 0.52), and with the assessment GDS (kappa range 0.29 - 0.75, mean = 0.52). One item showed evidence of bias when comparing the two T-GDSs, and two items when comparing the initial T-GDS to the GDS don e during the assessment. The mean number of symptomatic responses was not significantly different for the T-GDS versus assessment administra tion but did decline slightly when comparing the two T-GDSs. ROC curve analyses showed good agreement between the clinical diagnosis and the T-GDS. CONCLUSION: The GDS appears to maintain its reliability and va lidity when administered via telephone and thus may be useful for a va riety of epidemiological and clinical purposes.