Original article
Psychological risk factors for cardiac-related hospital readmission within 6 months of coronary artery bypass graft surgery

https://doi.org/10.1016/j.jpsychores.2006.09.008Get rights and content

Abstract

Objective

The objective of this study was to examine the psychological risk factors for cardiac-related readmission within 6 months of coronary artery bypass graft surgery (CABG).

Methods

Consecutive patients awaiting elective CABG (N=119; 100 males and 19 females), with a mean age of 63.3 years, completed a battery of psychosocial measures in a three-stage repeated-measures design. Relevant medical data were also extracted from patients' medical records 6 months postoperatively to allow for the examination of potential covariates.

Results

Two psychological variables, increased postoperative anxiety and increased preoperative depression, were identified as risk factors for cardiac-related readmission independent of the only significant covariate identified, cardiopulmonary bypass time.

Conclusion

Anxiety in the immediate postoperative period and, to a lesser extent, preoperative depression are important determinants of health care utilization postdischarge. Further research to clarify the psychological factors that are predictive of readmission, and that attempt to determine both the underlying cause of readmissions and potential mechanisms through which psychological factors act is recommended. Such research may highlight potential factors to target in interventions and the best time at which to intervene.

Introduction

Coronary artery bypass graft surgery (CABG) is a commonly used medical procedure for the treatment of coronary artery disease (CAD). Following CABG, it has recently been reported that between 7.4% and 19.1% of patients are readmitted for cardiac-related causes [1], [2], [3], [4]. Specific reasons for readmission have included angina, with and without shortness of breath, arrhythmia, wound infection, myocardial infarction (MI), angioplasty, and repeat CABG [1], [2], [3], [4]. These readmissions have adverse effects for both patients, in terms of quality of life and well-being, and for the health care system, in terms of economic costs [4]. While medical factors, including gender, left ventricular ejection fraction (LVEF), previous MI, and chronic renal insufficiency, are important predictors of cardiac-related readmission [1], [2], [3], [5], they alone do not explain the wide variation in this outcome. Thus, researchers have begun to examine psychological factors as a further means of explaining both physical health outcomes in general, and cardiac-related readmissions in particular, following CABG.

To date, the psychological functioning variable of primary interest has been depression. Preoperative depression has been identified as a predictor of higher readmission rates within the first 6 months postoperatively [1], [4], [5], [6]. Similarly, postoperative depression has been identified as a significant predictor of cardiac events and readmissions within 12 months of CABG, independent of disease severity [2]. In the only published study identified, postcardiac event anxiety in a mixed cardiac sample, including CABG patients, was not detected as a significant predictor of the length of all-cause or cardiac-related readmission 6 months after the initial cardiac event [5]. CABG-related posttraumatic stress disorder (PTSD) has yet to be examined as a predictor of readmission, but patients with PTSD precipitated by MI have been reported to be less likely to adhere to medication and, as a result, have experienced increased cardiac readmissions and mortality 6–12 months post-MI [7], [8]. Thus, the purpose of the current study was to identify psychological risk factors (preoperative and postoperative) for cardiac-related hospital readmission within 6 months of CABG, independent of covariates. Two sources of information were drawn upon to generate directional hypotheses: previous findings regarding psychological functioning variables as predictors of cardiac-related readmission, and previous research examining psychological functioning variables as predictors of other long-term physical outcomes in patients with cardiac conditions. From these findings, it was hypothesized that increased depression, anxiety, and PTSD would act as risk factors for CHD and surgery-related readmission within 6 months of CABG.

Section snippets

Participants

Consecutive patients awaiting elective isolated CABG or combined CABG/valve surgery at two South Australian hospitals between April 2002 and June 2003 were eligible to participate (N=140); all patients requiring emergency surgery were excluded. Consistent with previous studies [9], [10], both isolated CABG patients and combined CABG/valve surgery patients were included because of similarities in the procedure and in the course of physical and psychological recovery.

Of the 140 eligible patients,

Independent variables

Preoperatively, 17 patients (14.3%) were depressed, 18 patients (15.1%) were anxious, and 9 patients (7.3%) satisfied requirements for significant PTSD. In the immediate postoperative period, 17 patients (15.7%) were depressed, 33 patients (30.6%) were anxious, and 3 patients (2.8%) satisfied requirements for significant PTSD. With regard to change over time, of the 17 patients who were depressed preoperatively, in the immediate postoperative period, 8 patients remained depressed, 7 patients no

Discussion

Readmission following cardiac surgery is an adverse outcome that has deleterious effects both for patients and for the health care system. In the current study, 17.9% of patients who survived to hospital discharge were readmitted for CHD and surgery-related reasons within 6 months of CABG. This figure is higher than the 7.4–14% reported by other researchers who have examined psychological functioning as a risk factor for readmission [1], [2], [4], but is not as high as the cardiac-related

Acknowledgments

Support for this research was provided by Flinders University RSM and URB grants to Melissa Oxlad. Thanks to the staff of the Cardio-Thoracic Surgical Unit, in particular Trish Smith, Tina Wong, and Mary Ann Duggan, for their assistance with administrative information, patient recruitment, and access to medical data. We thank Kylie Lange for assistance with statistical methods, and the patients with cardiac conditions for their participation in this project.

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