Post-MI Readmission Risk and Causes Vary By Time, Analysis Shows

Nearly 40 percent of readmissions in the three months following myocardial infarction (MI) occurred within the first 15 days, and these early readmissions stemmed chiefly from cardiovascular causes. Those findings, from a new large single-center analysis at Cleveland Clinic, argue for initiating readmission prevention strategies well before MI patients are discharged, the researchers note.

“Our analysis suggests that the factors leading to readmission after MI are often likely to be embedded within the index hospitalization,” says Umesh N. Khot, MD, lead author of the study, published as a letter in the August 2017 issue of the Journal of the American College of Cardiology. “Efforts to prevent readmission need to account for the changes in risk over time that we observed, and these efforts should start early during the index admission.”

In search of better value in MI care

He and colleagues undertook their analysis to better define the risk of readmission after MI over time and by cause of readmission. “As reimbursement continues to shift toward bundled payments, understanding when and why patients are at highest risk of readmission is key to providing quality care and managing costs,” explains Dr. Khot, Vice Chairman of Cardiovascular Medicine at Cleveland Clinic.

They retrospectively identified all patients discharged from Cleveland Clinic’s main campus hospital with a principal diagnosis of MI from April 2008 to June 2012. The institutional billing system was used to identify all readmissions to the Cleveland Clinic health system within 90 days of the index MI. In all cases the primary cause of readmission was assigned to one of four categories:

• MI-related
• Other cardiovascular (CV)-related
• Non-CV-related
• Planned

Major findings of the study

Among the 3,069 patients discharged after an index MI, 494 readmissions occurred within three months of discharge. Key observations included the following:

• 232 of the 494 readmissions (47 percent) were either MI- or other CV-related
• 191 of 494 readmissions (39 percent) occurred within the first 15 days; risk of readmission dropped rapidly early in the post-discharge period
• Risk of MI-related and other CV-related readmissions was highest immediately after discharge (i.e., within 15 days) and declined steadily thereafter
• After about 15 days, non-CV-related readmissions overtook MI-related readmissions as the leading readmission category and remained so throughout the rest of three-month follow-up

“We found that both the risk and primary cause of readmission changed markedly over time,” says co-author Michael J. Johnson, MD, an interventional cardiology fellow at Cleveland Clinic. “These findings contrast with prior studies suggesting that the causes of post-MI readmission did not vary substantially over time.”

He notes that this is one of the first investigations to evaluate the risk and cause of readmission in the second and third months following discharge after MI. The study showed that readmission risk during this time was substantially lower than in the first month after discharge and remained relatively constant.

Messages for providers and payers alike

While acknowledging the limitations of a single-center retrospective study like this, including the inability to capture readmissions outside the Cleveland Clinic health system, Dr. Khot says this investigation offers several notable takeaways.

“The risk of post-MI readmission was highest right after discharge — especially for MI-related and other CV-related causes — and plummeted by nearly half within 15 days after discharge,” he observes. “This suggests readmission is often apt to be linked to aspects of the initial hospitalization. So strategies to curb readmissions should start on the day of the admission, not the day of discharge.”

He adds that the finding of variance in readmission risk over time and by cause might call for “a more nuanced approach” to preventing readmissions and improving the quality of MI care. “Factoring in such nuances may make sense both for hospitals and for the payers that hold hospitals accountable for post-MI readmissions,” Dr. Khot concludes.