Patient Health Questionnaire-9 score and adverse cardiac outcomes in patients hospitalized for acute cardiac disease

Objective: The Patient Health Questionnaire-9 (PHQ-9) is increasingly used as a depression assessment tool in cardiac patients. However, in contrast to older depression instruments, there is little data linking PHQ-9 scores to adverse cardiac outcomes. Our goal was to evaluate whether higher PHQ-9 scores were predictive of subsequent cardiac readmissions among depressed patients hospitalized for an acute cardiac event. Methods: Patients diagnosed with depression during hospitalization for acute coronary syndrome, heart failure, or arrhythmia were enrolled in a randomized depression management trial. Participants were administered PHQ-9 at enrollment, and data was collected regarding cardiac readmissions and mortality over the next 6 months. To evaluate the independent association of PHQ-9 score with subsequent cardiac readmission, Cox regression analysis that included relevant sociodemographic and medical covariates was used. Survival analysis examining time to first event, stratified by quartile of initial PHQ-9 score, was performed using Kaplan-Meier curves and log-rank test for trend. Analyses were then repeated using a composite (cardiac readmission or mortality) outcome. Results: Among 172 subjects, 62 (36.0%) had a cardiac-related rehospitalization. Higher initial PHQ-9 score predicted cardiac-related rehospitalization, independent of multiple relevant covariates (hazard ratio 1.09 [95% confidence interval = 1.02-1.17]; p = 0.015). On survival analysis, log-rank test for trend revealed a significant rise in event rates across increasing PHQ-9 quartiles (chi(2) = 6.36; p = 0.012). Findings were similar (p < .05) for the composite outcome. Conclusion: In depressed cardiac patients, each additional point on the PHQ-9 was independently associated with a 9% greater risk of cardiac readmission over the subsequent 6 months. (C) 2013 Elsevier Inc. All rights reserved.