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

objectiveThe 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.

methodsPatients 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 6months. 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.

resultsAmong 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 (χ(2)=6.36; p=0.012). Findings were similar (p<.05) for the composite outcome.

conclusionIn depressed cardiac patients, each additional point on the PHQ-9 was independently associated with a 9% greater risk of cardiac readmission over the subsequent 6months.