OBJECTIVE: To prospectively evaluate the reliability and validity of the Collateral Source Geriatric Depression Scale (CS-GDS) administered by telephone (T-CS-GDS) in patients undergoing outpatient comprehensive geriatric assessment. SUBJECTS: Eighty-three geriatric patients evaluated in a 1-year period at the outpatient Geriatric Assessment Center of the University of Nebraska Medical Center. METHODS: The 30-item CS-GDS was completed by the collateral source of all patients on three occasions: by telephone several days before their assessment, face-to-face during their assessment visit and several days later, again by phone. During their assessment, all patients were evaluated by one of three geriatric psychiatrists who were blinded to CS-GDS results. The test retest reliability of the T-CS-GDS was measured by comparing the results of the two phone interviews. The construct validity of the T-CS-GDS was estimated by comparing the results of the initial T-CS-GDS with the CS-GDS obtained during the comprehensive assessment. The criterion validity of the T-CS-GDS was estimated by comparing the results of the T-CS-GDS with the clinical diagnosis of depression assigned by the psychiatrists. RESULTS: The individual items of the initial T-CS-GDS showed substantial concordance with the second T-CS-GDS (kappa range 0.41-0.8, mean = 0.61) and with the assessment GDS (kappa range 0.33-0.85, mean = 0.61). Twelve items showed evidence of bias when comparing the two T-CS-GDSs and four items when comparing the initial T-CS-GDS with the CS-GDS done during the assessment. The mean number of symptomatic responses was not significantly different for the T-CS-GDS vs assessment administration but did decline slightly when comparing the two T-CS-GDSs. ROC curve analysis showed good agreement between the clinical diagnosis and the T-CS-GDS. CONCLUSION: The CS-GDS appears to maintain its reliability and validity when administered via telephone and thus may be useful for a variety of epidemiologic and clinical purposes.
OBJECTIVE: To prospectively evaluate the reliability and validity of the Collateral Source Geriatric Depression Scale (CS-GDS) administered by telephone (T-CS-GDS) in patients undergoing outpatient comprehensive geriatric assessment. SUBJECTS: Eighty-three geriatric patients evaluated in a 1-year period at the outpatient Geriatric Assessment Center of the University of Nebraska Medical Center. METHODS: The 30-item CS-GDS was completed by the collateral source of all patients on three occasions: by telephone several days before their assessment, face-to-face during their assessment visit and several days later, again by phone. During their assessment, all patients were evaluated by one of three geriatric psychiatrists who were blinded to CS-GDS results. The test retest reliability of the T-CS-GDS was measured by comparing the results of the two phone interviews. The construct validity of the T-CS-GDS was estimated by comparing the results of the initial T-CS-GDS with the CS-GDS obtained during the comprehensive assessment. The criterion validity of the T-CS-GDS was estimated by comparing the results of the T-CS-GDS with the clinical diagnosis of depression assigned by the psychiatrists. RESULTS: The individual items of the initial T-CS-GDS showed substantial concordance with the second T-CS-GDS (kappa range 0.41-0.8, mean = 0.61) and with the assessment GDS (kappa range 0.33-0.85, mean = 0.61). Twelve items showed evidence of bias when comparing the two T-CS-GDSs and four items when comparing the initial T-CS-GDS with the CS-GDS done during the assessment. The mean number of symptomatic responses was not significantly different for the T-CS-GDS vs assessment administration but did decline slightly when comparing the two T-CS-GDSs. ROC curve analysis showed good agreement between the clinical diagnosis and the T-CS-GDS. CONCLUSION: The CS-GDS appears to maintain its reliability and validity when administered via telephone and thus may be useful for a variety of epidemiologic and clinical purposes.