Perforated diverticulitis is a challenging disease with a spectrum of severity and varied clinical presentations. Patients with signs of hemodynamic instability or diffuse peritonitis undergo urgent surgery, while those without are increasingly being managed without an operation on their index admission. Over the last decade, there has been a shift toward nonoperative management for perforated diverticulitis with little data to guide clinicians on which patients are at risk for failing nonoperative management. Since there are no large U.S. population based studies evaluating non-elective readmissions and the risk factors for readmissions in this patient population, our results are not comparable to those in the literature. A smaller population study performed in the United Kingdom evaluating patients with perforated diverticulitis managed nonoperatively found that 203 of 767 (26.5%) patients required non-elective readmission at 1-year follow-up [10]. Of those non-electively readmitted, 3% required an emergency operation. Their study reported a non-elective readmission rate two times that of our study (26.5% versus 12.4%.) This may be due to their 1-year follow-up study timeframe when compared to our 30-day follow-up study timeframe. Their study also differed in the number of patients requiring emergency surgery upon readmission (3%) compared to our study (27.6%).
Several small retrospective studies have evaluated the success rates of the nonoperative management of perforated diverticulitis at index admission and identified the risk factors for failed management. In a cohort of 132 patients with perforated diverticulitis, Sallinen et al. [4], reported the successful non-operative management of 112 (85%) with 20 patients (15%) requiring emergent surgery. They identified abundant or distant free air and fluid in the fossa of Douglas on computed tomography (CT) imaging to be risk factors for nonoperative treatment failure [4]. In another study of 64 patients, Titos-Garcia et al. [5], found nonoperative management was successful in 54 patients (83.1%) with extraluminal air identified on their index admission for complicated diverticulitis [5]. Their work echoed the work of Sallinen et al. [4], in that distant free air on CT imaging was a risk factor for failed nonoperative management. Interestingly, two other studies reported a higher success rate of nonoperative management in patients with distant free air when compared to pericolic air [6, 8]. Both of these studies reported similar overall success rates of nonoperative management with Dharmarajan et al. [6], reporting success in 131 of 136 (91%) patients and Costi et al. [8], reporting success in 36 of 39 (92.3%) patients. Risk factors for nonoperative failure reported by Costi et al. [8], included severe sepsis, previous antibiotic therapy, duration of symptoms prior to presentation, higher CRP and WBC values, and presence of fluid in the pouch of Douglas on CT imaging. These studies did not report on readmission rates. A systematic review by Chua et al. [2], revealed 407 of the 479 (85%) included patients with acute perforated diverticulitis were successfully managed non-operatively. Hartmann’s procedure and resection with anastomosis with or without stoma were the most common operations performed in patients who failed nonoperative treatments [2].
While our study cannot be directly compared to earlier studies since we looked at 30-day readmissions, our study reports a similar success rate of nonoperative management at 87.6%. We did not report on CT imaging findings including volume or location of pericolic air or intraabdominal fluid. The NRD does not include laboratory or imaging data for comparison. We found the greatest independent predictors of readmission were patient disposition, index LOS, and insurance status. A longer LOS on the index readmission may highlight longer times to resolve the initial disease process or patients presenting with more severe disease.
To our knowledge, this is the only population-based study and the largest study in the United States evaluating the predictors of nonoperative treatment failure in this distinct patient population. Our study echoes that nonoperative management of acute perforated colonic diverticulitis is safe and effective for most stable patients. However, the decision to employ a nonoperative approach to manage perforated colonic diverticulitis should be based on individual patient characteristics including comorbid diseases, morbidity of emergent surgery, ongoing symptoms, and the complexity and severity of disease at presentation. Early recognition of patients who show clinical signs of persistent perforation after nonoperative management remains crucial to the success of this strategy. Considering the finding that 27.6% of readmitted patients required an emergent operation, clinicians should pay special attention to those at risk for readmission. The highest readmission rates were found in those discharged with home health, which may cautiously be interpreted that these patients were either frailer on admission or upon discharge. Our study also found that readmitted patients were more likely to have Medicare compared to private insurance. This is an alarming disparity that deserves attention. These findings highlight a vulnerable population and an unsatisfactory trend in the management of perforated diverticulitis. This should be considered when caring for diverse populations of patients and creates opportunities for quality improvement projects.
Our study has many strengths including a large sample size of 143,546 and vast diversity geographically. However, database studies may allow for skewed data as they rely on the proper coding that may overestimate or underestimate the disease being studied. With a large sample size, it is also possible that statistical differences detected are amplified and may not be clinically meaningful. Additionally, this study is limited by its retrospective methodology and the NRD does not include data points of interest including radiographic findings and laboratory values.
In conclusion, the nonoperative management of perforated diverticulitis may be a safe and effective way to treat stable patients. However, if nonoperative management fails, this study found that 27.6% of readmitted patients will require surgical intervention. The high morbidity associated with delayed surgery mandates patient care is tailored to individual patient characteristics including those characteristics that portend a higher risk of readmission. Finally, the disparities related to insurance coverage need to be promptly addressed with future studies. There is an opportunity to study this patient population prospectively to better define candidates safe for nonoperative management.