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.