Psychometric assessment of the Cardiac Depression Scale Short Form in cardiac outpatients

Abstract

Background: Depression is common in patients with cardiovascular disease and is a risk marker for increased mortality. The valid and reliable detection of depression is fundamental to the appropriate management of these patients. Aim: The aim of this study was to evaluate the psychometric characteristics of the Cardiac Depression Scale Short Form 1 (DS-SF1) and the Cardiac Depression Scale Short Form 2 (DS-SF2) for screening cardiac outpatients in clinical settings. Methods: Adult cardiac outpatients attending a cardiovascular clinic completed the Cardiac Depression Scale (CDS), two versions of the DS-SF (DS-SF1 and DS-SF2) and the Physical Health Questionnaire 2 (PHQ2-Y/N) prior to their cardiac consultation. Results: Data from 326 patients (224 men; mean±SD age 66.25±14.39 years) were analysed. The DS-SF1 (mean score 16.28±5.70) had good construct validity with the CDS (r=0.77; p<0.0001), adequate convergence with the PHQ2-Y/N (r=0.59; p<0.0001) and good internal consistency (α=0.73). The DS-SF2 (mean score 15.80±6.80) had a better construct validity with the CDS (r=0.84; p<0.0001) and the PHQ2-Y/N (r=0.69; p<0.0001) and better internal consistency (α=0.82). The DS-SF2 showed strong criterion validity with the CDS with a DS-SF2 3/415 cut-point yielding 90% sensitivity and 73% specificity (area under the curve 0.92) for detecting depression (CDS 3/495). Conclusion: These findings confirm the excellent psychometric properties of the DS-SF2 as an ideal tool for screening depression in cardiac patients in clinical practice. The DS-SF2 should be regarded as the definitive version of the DS-SF.