Author + information
- Umesh N. Khot, MD∗ (, )
- Michael J. Johnson, MD,
- Ashley M. Lowry, MS,
- Jeevanantham Rajeswaran, PhD,
- Samir Kapadia, MD,
- Mehdi H. Shishehbor, DO, MPH, PhD,
- Venu Menon, MD,
- Stephen G. Ellis, MD,
- Pamela Goepfarth, RN, MBA and
- Eugene H. Blackstone, MD
- ↵∗Heart and Vascular Institute Center for Healthcare Delivery Innovation J2-4, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, Ohio 44122
Twenty percent of patients who experience a myocardial infarction (MI) will be readmitted within 30 days of discharge (1,2). Previous studies have suggested that the timing of readmission after MI by cause is relatively uniform (2). Because hospital reimbursement and payment structures continue to change and move toward bundled payments (3), understanding when and why patients are at greatest risk for readmission is critical to help provide quality care and manage costs. We sought to further evaluate the risk of readmission over time by cause after MI.
We retrospectively identified all patients discharged alive from our main hospital with a principal diagnosis of MI from April 2008 until June 2012 using discharge International Classification of Disease-9 (ICD-9) diagnosis codes (ICD 410 to 410.9). All readmissions to our health system within 3 months were identified using our institutional billing system. Readmissions outside of our health system were not available and not included in the analysis. The primary cause of readmission was identified using principal diagnosis billing codes and categorized into 4 groups: MI-related, other cardiovascular (CV)−related, non−CV-related, or planned. Time-varying instantaneous risk of readmission was estimated for all readmissions and readmissions by cause using a nonlinear parametric temporal decomposition model (4).
The study cohort consisted of 3,069 patients discharged alive after an index MI. Within 3 months of the index MI, there were 494 readmissions. Forty-seven percent (232 of 494 patients) were either MI- or other CV-related. Thirty-nine percent (191 of 494 patients) occurred within the first 15 days. The instantaneous risk of readmission after MI was highest immediately after discharge and then dropped rapidly early in the post-discharge period (Figure 1A). The risk of MI-related and other CV-related readmissions was highest immediately after discharge, and after approximately 15 days, non−CV-related causes posed the highest risk for readmission (Figure 1B). During the second and third months after discharge, the risk of readmission was substantially lower and remained relatively constant.
Our findings contrasted with previous studies that suggested that the causes of readmission after MI did not vary substantially over time (1,2). Our results demonstrated that both the risk and primary cause of readmission changed dynamically over time. Nearly 40% of readmissions within 90 days occurred within the first 15 days, and these readmissions were predominantly CV-related. This finding suggested that the factors that led to these readmissions were likely embedded within the index hospitalization. Readmission prevention strategies should thus begin on the day of admission and not on the day of discharge. As pressure builds to decrease length of stay to manage costs, premature discharge could lead to an increased rate of readmission (5), paradoxically increasing overall costs for a hospital system. Furthermore, as payment bundles for MI might soon extend to 90 days (3), our study was one of the first to address the risk and cause of readmission in the 31- to 90-day window. Our finding of overwhelming non-CV readmissions in this time highlighted the challenges for cardiologists in reducing the rate of these readmissions. Close collaboration with other clinical teams, such as primary care and internal medicine specialists dealing with chronic disease processes, might be needed to affect these readmissions. We acknowledged limitations inherent to a single-center retrospective study.
The risk of readmission after MI was highest immediately after discharge, particularly for CV-related readmissions and dropped by almost one-half within 15 days of discharge. Efforts to prevent readmission need to account for this change in risk over time and prevention strategies should begin early during the index admission. A more nuanced approach based on the risk and cause of readmission over time might be a more preferred method to improve quality of MI care and to hold hospitals accountable for readmissions after MI.
Please note: The primary funding source was unrestricted philanthropic support to the Heart and Vascular Institute Center for Healthcare Delivery Innovation, Cleveland Clinic. The funding source had no role in the design or conduct of the study; collection, management, analyses, or interpretation of the data; preparation, review, or approval of the manuscript; or the decision to submit the manuscript for publication. Dr. Khot serves as a consultant for AstraZeneca. All other authors have reported that they have no other relationships relevant to the content of this paper to disclose.
- 2017 American College of Cardiology Foundation