ACS NSQIP Formula May Predict Readmission Risk After Surgery

Norra MacReady

April 03, 2014

Existing formulas used to identify patients at high risk for postsurgical complications may also prospectively identify patients at high risk for unplanned readmission after surgery, according to a recent study. Among patients deemed to be at very high risk for complications, defined as a risk higher than 15% based on the American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) model, the odds of readmission were 10-fold greater than those of patients considered to be at very low risk.

"Having shown that the risk of rehospitalization is closely predicted by the risk of major complications, it should be feasible for ACS NSQIP hospitals to identify high risk for rehospitalization using the ACS NSQIP prediction model," write Laurent Glance, MD, from the Department of Anesthesiology, University of Rochester School of Medicine, New York, and colleagues in an article published online March 5 in JAMA Surgery.

"Although the complication risk index is not currently available in real time, ACS NSQIP could provide participating hospitals with the means of calculating a patient’s risk index at the time of data collection. Physicians and hospitals could then use this information to guide efforts to reduce the likelihood of rehospitalization through early detection and treatment."

Postdischarge Complications Key

To learn whether the ACS NSQIP model, which was designed to prospectively identify patients at risk for postsurgical complications, could also be used to predict readmission risk, the researchers examined hospital readmissions among 143,232 patients who underwent noncardiac surgery in 2011 in 400 hospitals who were included in the ACS NSQIP participant data file. The ACS NSQIP data file contains detailed information on patient demographics, along with medical information such as preoperative risk factors, postoperative mortality, and complications.

Identifying high-risk patients and implementing preventive measures before the complications occur could have a payoff that is "immediate and substantial," write Dr. Glance and colleagues.

The overall rate of unplanned readmissions among this patient population was 6.8%. On initial exploratory analysis, patients with any postdischarge complications had a readmission rate of 78.3% compared with 12.3% among patients with in-hospital complications and 4.8% for patients who experienced no complications (P < .001 for both comparisons). The relationship between postdischarge complications and 30-day readmission rate persisted in a multivariate analysis that controlled for baseline disease severity and surgical complexity.

Among patients deemed to be at very high risk of for complications, defined as a risk higher than 15%, as predicted by ACS NSQIP criteria, the odds of readmission were 10-fold greater than those of patients considered to be at very low risk for hospital readmission (adjusted odds ratio [AOR], 10.35; 95% confidence interval [CI], 9.16 - 11.70). The AOR for patients with a high risk for complications was 6.57 (95% CI, 5.89 - 7.34) compared with those at very low risk, and for patients at moderate risk, the AOR was 3.96 (95% CI, 3.57 - 4.39; P < .001 for all comparisons).

Predischarge complications were associated with an AOR of 2.09 (95% CI, 1.86 - 2.35) compared with no complications, but postdischarge complications carried a 61-fold increase in readmission risk (AOR, 61.11; 95% CI, 55.87 - 66.83; P < .001 for all comparisons).

"Based on these findings, we conclude that a patient's risk of developing a serious postoperative complication is a powerful predictor of unplanned rehospitalization," the authors state. Providing clinicians the tools to identify high-risk patients early on "may be the key to preventing poor outcomes down the line."

In an accompanying editorial, Sandra DiBrito, MD, and Martin A. Makary, MD, MPH, from the Department of Surgery, Johns Hopkins Hospital, Baltimore, Maryland, describe the study as "the most detailed study of surgical readmission of its kind." They point out that interventions such as "better discharge teaching, home health support, follow-up calls, early clinic visits, and even home health monitoring," as well as other outpatient services such as 24-hour telephone assistance from nurses and other clinicians, might help in the detection and management of complications before they become serious.

However, Dr. DiBrito and Dr. Makary warn, "we must also remember that social, economic, and cultural characteristics can influence readmission rates." They conclude that it may be critical to account for these differences "before penalizing hospitals that disproportionately and admirably care for populations at higher risk for readmission."

The authors and editorialists have disclosed no relevant financial conflicts of interest.

JAMA Surg. Published online March 5, 2014. Article abstract, Editorial extract


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