Background: Depressive symptoms, assessed by using self-report scales, are present at a striking rate of 45% in patients with chronic kidney disease (CKD) at dialysis therapy initiation. These scales may emphasize somatic symptoms of anorexia, sleep disturbance, and fatigue, which may coexist with chronic disease symptoms and lead to overestimation of depression diagnosis. No study has validated these scales in patients with CKD before dialysis therapy initiation.
Study design: We conducted a diagnostic test study in participants with CKD to investigate the screening characteristics of 2 depression self-report scales against a gold-standard structured psychiatric interview.
Setting & participants: 272 consecutively recruited outpatients with stages 2 to 5 CKD not treated by dialysis were studied.
Index tests: The Beck Depression Inventory (BDI) and the 16-item Quick Inventory of Depressive Symptomatology-Self Report (QIDS-SR(16)) depression screening scales were administered to all participants.
Reference test: A structured Diagnostic and Statistical Manual of Mental Disorders (Fourth Edition)-based interview, the Mini International Neuropsychiatric Interview, was administered by trained persons blinded to self-report scale scores.
Results: 57 of 272 (21%) patients had major depression according to the reference test. The best cutoff scores by means of receiver/responder operating characteristic curves to identify a major depressive episode were 11 for the BDI and 10 for the QIDS-SR(16). Sensitivities were 89% (95% confidence interval [CI], 78 to 96; BDI) and 91% (95% CI, 80 to 97; QIDS-SR(16)), whereas specificities were 88% (95% CI, 83 to 92; BDI) and 88% (95% CI, 83 to 92; QIDS-SR(16)). The positive and negative likelihood ratios for these cutoff scores were 7.6 and 0.1 (BDI) and 7.5 and 0.1 (QIDS-SR(16)).
Limitations: Single-center study and a sample not representative of US demographics.
Conclusions: We found that a BDI score of 11 or higher was a sensitive and specific cutoff value for identifying a major depressive episode in patients with CKD not on dialysis therapy. Both the BDI and QIDS-SR(16) are effective screening tools.