Reliability and validity of the geriatric depression scale in elderly individuals with coronary artery disease

The prevalence of depression in individuals with coronary artery disease (CAD) is high. The Geriatric Depression Scale (GDS) is a broadly used tool to screen for depression in elderly individuals. In Brazil, the psychometric properties of the short version have not been adequately assessed. To evaluate the psychometric properties of the short version of the GDS in patients with CAD treated at a Cardiology Outpatient Clinic. The present is a cross-sectional study that assessed 209 elderly individuals (> or = 65 years) with CAD using the GDS-15, the Cumulative Illness Rating Scale for Geriatrics (CIRS-G), the Brazilian OARS Multidimensional Function Assessment Questionnaire (BOMFAQ) and The Cambridge Examination for Mental Disorders of the Elderly (CAMDEX). The internal consistency of the GDS-15 was calculated through the KR-20. A factorial analysis of this scale was carried out. The GDS-15 scores were compared with the diagnoses of depression (DSM-IV) for the validity of criteria. At the analysis of concurrent validity, the same scores were correlated with those of the CAMDEX, mini-mental state examination (MMSE), Cambridge Cognitive Examination (CAMCOG) and BOMFAQ depression scales. Clinical depression was diagnosed in 35.71% of the sample assessed according to the DSM-IV. For the diagnosis of major depression or dystimia, the cutoff 5/6 presented moderate accuracy (AUROC = 0.84), sensitivity of 79.92% and specificity of 78.29%. The internal consistency was 0.80. At the factorial analysis, three obtained factors explained 52.72% of the total variance that was observed. The GDS-15 scores correlated with those of the CAMDEX depression scale. In general, the GDS-15 presented good reliability and validity (concurrent and of criterion). In cardiologic settings, its use, which is simple and fast, can be utilized in the screening for depression.