In April of 2012, the CMS proposed a new methodology for adjusting hospital reimbursements based upon the number of readmissions, with excessive readmissions leading to decreased payments.16
Furthermore, the Agency for Healthcare Research and Quality has recently funded a program entitled Project RED (re-engineered discharge) which focuses upon patient education that facilitates successful hospital discharge.17
With the increased attention placed upon readmissions in our current healthcare climate, it is essential to understand risk factors and how readmissions might be prevented.
The reasons for readmission following a General Surgery procedure are multi-factorial. However, the common denominator which appears in our data, as well as other studies in the literature, is that of postoperative complications. Studies examining patients who were readmitted following colon resection cite postoperative blood transfusion, dehydration, and infection as being the complications leading to significant rates of readmission.9,11,12,18
Similarly, among patients undergoing pancreatic resections, postoperative wound infections, pancreatic fistulas, and delayed gastric emptying have been reported to be associated with increased risk of readmission.4,8,19,20
Our study provides further evidence that postoperative complications are the most significant independent risk factor leading to hospital readmissions. Our analysis shows that any postoperative complication, independent of patient- and procedure-specific risk factors, increases risk of readmission by a factor of four. Furthermore, patients with postoperative sepsis or UTI were around five times more likely to be readmitted than those patients without, and postoperative wound infections and postoperative pulmonary complications both carried an approximate three and a half-fold increase in readmission rates.
The results of our analysis also demonstrate that certain complications represent a disproportionately large portion of readmissions. For example, postoperative blood transfusions doubled a patient’s risk for readmission and represented over 25% of our readmitted patient population. On the other hand, postoperative UTIs accounted only for 9.2% of readmissions, but they actually carried the highest risk for readmission of all complications studied (OR=5.08). Understanding which postoperative complications carry larger risks will be helpful in determining how to allocate resources in order to prevent the complications, and readmission, following surgery.
We also show that the number of complications, along with their timing, influence the risk of readmission. Patients with one complication were over two times likely to be readmitted than those without any postoperative complications. Furthermore, patients with two complications were over twice as likely to be readmitted as patients with only one complication, and over five times as likely when compared to patients without complications. Our data reveal, however, that patients who have three or more complications have a slightly lower risk of readmission than those who only have two complications. There could be several ways to interpret this finding. First, we demonstrate that patients with a three or more complications have substantially longer lengths of stay (24 days compared to 12 days or less for two or fewer complications), and are thus less likely to be discharged prematurely before the complications are completely treated and/or appropriate transition of care has been arranged. This reasoning is further supported by the fact that patients whose complications occur during, not after, their index admission are more than half as likely to be readmitted. Finally, it could be that the severity of the complications, not the actual number, is driving the rate of readmission. Future prospective analysis will be needed to clarify this result.
In addition to postoperative complications, certain risk factors such as procedure type and preoperative length of stay were associated with readmission risk. While these variables cannot be changed in and of themselves, we do have an opportunity to intervene pre- and postoperatively if we know ahead of time that specific patients are at increased risk for readmission. Hendren and colleagues report that patients at risk for readmission following colectomy for colon cancer are more likely to be elderly, male, African American, and from a lower socioeconomic status.9
While our study did not find any significant association between age, race, gender and readmission, we do reveal that patients who undergo complex gastrointestinal surgery (pancreatectomy, hepatectomy, and colectomy), and have a preoperative length of stay greater than 24 hours are more likely to be readmitted than other patients.
Intra-abdominal General Surgery procedures are much more likely to be associated with postoperative complications than those outside the abdomen all together (e.g. mastectomy, parathyroidectomy, and thyroidectomy), and our study results further support this notion.21
Additionally, patients who are in the hospital for at least 24 hours prior to their surgery are likely to have greater exposure to nosocomial bacteria, further increasing the risk of an infectious complication following surgery. Multidisciplinary efforts by physicians, nurses, therapists and social workers, should be focused on these specific patient populations during preoperative clinic visits and throughout their hospital stay in order to minimize the risk of postoperative complications and readmission.
There are a few comorbidities which significantly affect the risk of readmission. Patients with disseminated cancer and open wounds are at nearly double the risk of readmission than those without. Patients with dyspnea are at further risk for readmission. When you compare preoperative comorbidities to the postoperative complications associated with readmission, they are undoubtedly related. Patients who are immunosuppressed, poor wound healers, and who have baseline pulmonary disease are vulnerable to complications which will increase the likelihood of postoperative readmission. There is an abundance of evidence within the literature to support that comorbidities such as diabetes, smoking, and immunosuppresion increase the risk of surgical site infections and postoperative pulmonary complications.22,23
However, our analysis underscores the notion that postoperative complications, independent of patient comorbidity, are associated with a four-fold increase in risk of readmission. Multiple comorbidities such as acute renal failure, ventilator dependence, and ascites, while associated with a high rate of readmission, were not statistically significant risk factors within our study. This is likely due to the small number of patients with these comorbidities within our cohort. Only three patients had preoperative renal failure, 11 were ventilator dependent, and 26 had ascites.
In early 2011, Atul Gawande introduced the idea of “hot spots” within the American healthcare system.24
Based upon healthcare utilization research, Gawande suggests that the sickest, most “difficult” patients account for the largest expenditure of healthcare dollars. Thus, if resources can be focused upon certain high-risk patient populations undergoing complex inpatient procedures, the number of postoperative complications could be considerably reduced and incidence of hospital readmission could be less frequent. As a result, the potential for healthcare savings could be quite significant.
Our data demonstrate that postoperative complications, in particular, drive readmission rates at our institution. Consequently, focusing our efforts on effectively preventing and appropriately managing postoperative complications in high-risk patients could greatly impact the number of readmissions following surgical procedures. Patients who experience postoperative complications are likely to have a more complex discharge plan involving wound care instructions, antibiotic regimens, and/or rehabilitation therapy, each of which could lead to a readmission if not properly executed following discharge from the hospital.25
There are at least three weaknesses to our study. First, the data were collected locally for a single institution, and the small study size leads to deficiencies in gaining statistical power. While large multi-institutional databases such as the NSQIP Participant User Files are extremely valuable, the data are de-identified, thus limiting the ability to capture patient readmissions. What is important to appreciate, however, is the impact that local data can have on quality improvement within single medical centers. It can be difficult to determine an institution’s quality risks using large-powered, multi-institutional studies, while here we show the value of local data.
Second, we utilized encounter-specific NSQIP variable to analyze the risk of readmission. It is possible that other factors which are not captured by the NSQIP database could be contributing to hospital readmissions. Furthermore, we should note that our method of detecting readmissions by linking our NSQIP data to our clinical data warehouse leaves the study vulnerable to underestimating readmissions. It is plausible that a patient might seek treatment for follow-up care at an outside institution. However, due to the fact that we are a regional tertiary care referral center, the majority of patients treated at our institution for their index admission are directed back here for care if a subsequent complication arises. In future studies, it might be possible to link multiple data sets which could capture patient readmissions at multiple institutions.
Finally, this study is exploratory with the aim of identifying factors associated with readmission following a general surgical procedure. Future studies with larger sample sizes should be utilized to build and validate predictive models for the risk of 30-day readmission. The results we have presented, however, offer a framework for institutions to think about when trying to address and prevent unplanned patient readmissions to the hospital.