What are the differences between the three most used classifications for acute colonic diverticulitis? A comparative multicenter study

Modified Hinchey, AAST, and WSES classifications are the most popular classifications for acute diverticulitis. 597 patients were retrospectively evalutated. AAST, WSES, and modified Hinchey classifications are similar in predicting complications, reintervention, and mortality.

A cute colonic diverticulitis represents one of the most rele- vant diseases in emergency general surgery.Proper clinical assessment of the pathology can help surgeons to stratify patients who may require tailored medical and surgical strategies as an adequate patient categorization is associated with more appropriate clinical management.To objectively identify the severity and consequent patient outcomes, one of the tools at surgeons' disposal is classification systems.2][3][4][5] As the oldest and most used system, Hinchey classification takes into consideration both preoperative and intraoperative findings.Although there have been several attempts to modify it, mainly with the aim of discriminating stages I and II, 2 there is still an objective difficulty in stratifying patients earlier.Therefore, the American Association for the Surgery of Trauma (AAST) and the World Society of Emergency Surgery (WSES) proposed two classifications that focus on patients' computed tomography (CT) images 5,6 (Fig. 1).To date, no studies have specifically compared these three classification systems in terms of clinical utility and outcomes, although there has been an attempt to compare the AAST and Hinchey classifications; however, the latter still represents the established scoring system for acute diverticulitis. 7The aim of the present study was to compare AAST, WSES, and modified Hinchey classifications of acute colonic diverticulitis in terms of their ability to predict the need for procedural intervention, mortality, hospital length of stay (HLOS), intensive care unit (ICU) admission, and com-medical centers.The study population was derived from a consecutive patient sample gathered from 2014 to 2021.Adult patients (older than 18 years) were included in the study if they were admitted with left-sided acute colonic diverticulitis.The present study has been registered at ClinicalTrial.org with the number NCT04596280.Having CT images obtained at the time of admission was an essential inclusion criterion.Each admission was inspected via chart review.Demographic and clinical data were collected, including age, gender, comorbidities (hypertension, cardiopathy, smoking status, diabetes mellitus, chronic obstructive pulmonary disease), and medication status (steroids, anticoagulation, and immunosuppression).The term "cardiopathy" included all the heterogeneous diseases or disorders of the heart that could potentially lead to heart failure or severe arrhythmias.In those patients presenting with either purulent or fecal diffuse peritonitis, suture of the skin was initially avoided and delayed in the following postoperative days.The primary outcome was the need for procedural intervention (operation or percutaneous drainage).Secondary outcomes included ICU admission, in-hospital complications (incisional surgical site infection, renal failure, deep vein thrombosis/pulmonary embolism, urinary tract infection, major adverse cardiac event, need for mechanical ventilation), reintervention rate, HLOS, and inhospital mortality.Both superficial and deep incisional surgical site infections were taken into consideration.Reinterventions were considered surgical operations required after the initial surgical treatment.Computed tomography images were examined by experienced radiologist reviewers from each participating center, and each scan was assigned an AAST grade, a WSES grade, and a modified Hinchey grade (Fig. 1).Radiologists were blinded to the interventions and outcomes prior to reviewing CT scans.The study was conducted according to the STROBE guidelines 8 (Supplemental Digital Content, http://links.lww.com/TA/D242).Data collection and analysis were performed according to the institutional guidelines and to the ethical standards of the Helsinki Declaration.

Statistics
A computerized spreadsheet (Microsoft Excel 2013; Microsoft Corporation; Redmond, WA) was used for data collection.Analyses were performed using SPSS version 23 (SPSS Inc., Chicago, IL).Descriptive statistics were calculated for all clinical variables; categorical variables are presented as n (%), and continuous variables are represented as median (interquartile range [IQR]).Shapiro-Wilk normality test was checked for continuous variables.Univariate analysis of unadjusted outcomes was performed using Pearson's χ 2 test or Fisher's exact test for categorical variables and the Kruskal-Wallis test for continuous variables.Adjusted outcomes were compared via logistic regression (need for procedure, morbidity, major complications, reinterventions, and mortality) and linear regression (HLOS) analysis.Receiver operating characteristic (ROC) curves were created, controlling for demographic and comorbidity risks.Nonparametric comparison of the modified Hinchey, AAST, and WSES ROC curves were compared, adjusting for covariates.Statistical significance was set at p = 0.05.

RESULTS
A total of 597 patients were enrolled in the study.Demographic and clinical characteristics are presented in Table 1.The mean age was 65 years, and 57% of the patients were female.Median body mass index was 25.1 kg/m 2 , and 29% of cases had ASA score ≥3.Thirty-five percent of patients had previous history of acute diverticulitis.The most common medical comorbidities were hypertension (41%), cardiopathy (19%), and current smoking (16%).Conservative management was attempted in 41% of cases (Table 2).In the remaining 59% of patients, several interventions were performed, and a percutaneous drain was placed in 3% of these patients.In-hospital outcomes are described in Table 2.

DISCUSSION
According to our analysis, the three selected classification systems were effective for predicting major outcomes including intervention, morbidity, reintervention, and HLOS; higher scores   were significantly related to increased complication rates (in general and for major complications alone) and need for surgery or reintervention.In contrast, only high grades (Hinchey Grade 4, AAST Grade 5, and WSES Grade 4) were independent risk factors for increased mortality.The modified Hinchey, AAST, and WSES classifications did not differ significantly in their ability to predict morbidity, reinterventions, or mortality.AAST grading was more accurate than the modified Hinchey and WSES classifications when evaluating the need for intervention (c-statistics: AAST = 0.836 vs. WSES = 0.824 vs. modified Hinchey = 0.813), and AAST was more accurate than modified Hinchey for predicting major complications (c-statistics: modified Hinchey = 0.757 vs. AAST = 0.736 vs. WSES = 0.709).This study aimed to compare the accuracy of the most frequently used classifications for acute diverticulitis.Few such comparisons are reported in the current literature.To our knowledge, only one study compared grading systems.Erbesole et al. retrospectively analyzed 129 patients with acute diverticulitis and compared the modified Hinchey classification and the AAST grading scale.They found that the need for operation c-statistics were 0.80 for Hinchey and 0.83 for AAST ( p = 0.35), and the complication c-statistics curve was 0.83 for AAST and 0.80 for Hinchey ( p = 0.33).In contrast, the AAST and Hinchey scores were less predictive for ICU admission, readmission, and mortality, with c-statistics less than 0.80.Therefore, the authors concluded that the AAST classification for acute diverticulitis is equivalent to the modified Hinchey classification for predicting procedural interventions and complications, but the AAST system is preferred to Hinchey because it can be applied preoperatively. 7However, the study was unable to achieve a definitive conclusion, as the sample size was relatively small and underpowered by the fact that it was conducted in a single-center setting.
0][11][12][13][14] In a review published in 2012, Klarenbeek et al. 14 proposed that a proper classification system could improve mutual communication between doctors from different specialties and support clinical decision making.
The principal limitation of the original Hinchey score is its lack of application in the preoperative setting as this system grades only intraoperative findings.The effort to improve the Hinchey classification with further sub-classifications has not addressed this weakness.Moreover, the modified classification still has important "gray" areas that are not adequately represented by the clinical and radiological findings.For example, the presence of bubbles close to the colon or far from the diverticular site, in the absence of significant peritoneal collections, would be difficult to properly classify with the Hinchey system. 15The AAST and WSES classification systems aimed to overcome the lack of preoperative specificity of the modified Hinchey classification by stratifying CT findings.Their spread and progressive use in the literature has raised the important question of these two scales could improve risk stratification and patient management.As stated by the European Society of Coloproctology, no CT scan-based classification is superior to others as a diagnostic tool for acute diverticulitis, and each center should adopt their preferred classification, in accordance with the radiologist personnel. 16his study has several limitations.First, some in-hospital items and follow-up criteria, such as the need for ICU admission, recurrence rate, and need for elective surgery, were not considered.However, we speculate that the addition of these outcomes would have reduced the significance of the results, as these outcomes can be potentially influenced by other clinical variables.Furthermore, the cohort of patients was selected from several centers, and clinical management practices may vary from hospital to hospital.Similarly, we did not consider patients who were discharged from general medicine departments with presumably mild disease.However, the strength of this study is the sample size, that was considerable.As a multicenter study, we were able to enroll a large enough patient population to adequately evaluate the secondary outcomes.
In conclusion, AAST, WSES, and modified Hinchey classifications are adequate tools in the management of left-sided acute colonic diverticulitis.All three classification systems are equally effective for predicting outcomes, like complications, need for reintervention, and mortality.American Association for the Surgery of Trauma and modified Hinchey scores result the most adequate for predicting the need for surgery and the occurrence of major complications.

Figure 1 .
Figure 1.Three most used classifications for diverticular disease.

TABLE 1 .
Demographics and Comorbidities

TABLE 2 .
Interventions, Outcomes, and Complications **Diversion without resection, total colectomy, dead as damage-control surgery or unknown.†% of overall surgeries: n = 342) ‡% of overall laparoscopic approaches: n = 167) §Superficial and Deep incisional surgical site infection; the % was calculated over the population of patients with a laparotomic incision (total number = 223).PLOS, postoperative length of stay; C-D, Clavien-Dindo.

TABLE 4 .
Adjusted Scoring Outcomes for Hinchey, AAST and WSES Classifications (Regression Analysis) Values with p < 0.005 in bold.