Introduction

Appendicitis is the most common cause of acute abdomen in adult that usually treated with emergent operation, with a 6.7–8.6% chance of occurrence in one's lifetime [1]. Appendectomy has been accepted as a standard treatment for a long time although conservative treatment with antibiotics has gained some attention in recent years [2, 3]. The advances in surgical techniques have significantly reduced the size of surgical incisions, improved pain management, and reduced complications [4]. Many factors affect the treatment outcomes of appendicitis, including the patient's age [5, 6], sex [7], physical status [5, 6, 8], and the degree of appendix inflammation [9, 10]. Several studies have reported an association between surgical delay and higher rate of appendiceal perforation, peritonitis, and postoperative complications. [11,12,13] Different from those patient or disease-related factors, the quality of surgery and surgical delay are factors that might get improved.

Tertiary care hospitals and regional hospitals differ in terms of their size, care processes, medical equipment, geographical location, and patient population. Studies have reported that some high-risk surgeries have better outcomes in tertiary care hospitals, reflecting the advantages of anesthesiology care and multidisciplinary teams in treating complex diseases and patients [14, 15]. However, appendectomy is thought to be an uncomplicated surgery, and hence, both tertiary care hospitals and regional hospitals have the ability to treat these patients. However, tertiary care hospitals have larger volume of critically ill patients and many life-threatening emergent operations with higher priority, which may lead to delays of diagnosis and surgery in patients with appendicitis because of their “stable” condition. In addition, as a basic surgery in general surgery, many trainees, such as resident physicians, may perform the surgery in tertiary care hospitals. Currently, there is a lack of adequate research on the variations in surgical outcomes between tertiary care hospitals and regional hospitals.

The aim of this study is to perform a multicenter retrospective analysis comparing surgical outcomes and the quality of care among adult patients undergoing appendectomy for acute appendicitis in tertiary care hospitals versus regional hospitals. This investigation may yield valuable insights with the potential to inform future healthcare planning and policy decisions, thereby potentially enhancing both healthcare system efficiency and patient outcomes.

Materials and methods

Patients and study design

This study is a multicenter retrospective observational study approved by the ethics committee of the institute review board of National Taiwan University Hospital (Protocol ID: 201904076RINA) and was carried out in accordance with the approved guidelines. Consecutive patients with acute appendicitis who underwent appendectomy from January 2014 to June 2018 at three hospitals were included. We included consecutive patients with acute appendicitis who underwent appendectomy between January 2014 and June 2018 at three hospitals. The three hospitals comprise of a tertiary care hospital (National Taiwan University Hospital, Taipei) and two regional hospital (National Taiwan University Hospital Hsinchu branch, and Yunlin branch). The inclusion criteria of the patients were (1) age ≥ 20 years, (2) admitted from emergency department, (3) with a preoperative diagnosis of acute appendicitis, and (4) underwent an urgent appendectomy. The study design and flow diagram of the patients are shown in Fig. 1. Total of 2158 patients were eligible for final analysis. The data were retrieved from National Taiwan University Hospital-integrated Medical Database.

Fig. 1
figure 1

Study design and flow diagram of the patient inclusion and exclusion criteria in this study

Full size image

Variables and outcome measures

All variables regarding patient demographics and clinical outcomes were collected from electronic medical record system, including age, sex, body mass index, educational status, personal medical history, substance use (cigarette, alcohol, betel nut), perioperative characteristics (data at triage in emergency room, surgical waiting time, operation time, intraoperative findings) and postoperative data (length of postoperative hospital stay and stay of intensive care unit, complications, and total hospital cost). The patient cohort was divided into two groups: regional hospital group and tertiary care hospital group, according to the hospital they were treated at. The tertiary care hospital refers to the National Taiwan University Hospital (Taipei), which was a referral hospital with more than 2600 beds during the study period; regional hospital refers to the National Taiwan University Hospital Hsinchu branch and Yunlin branch, both of them were regional hospitals with about 800 beds. The operation waiting time is defined as the period from patient triage in the emergency department to the beginning of the operation. This timeframe encompasses both the diagnostic process and the subsequent wait for surgery. A surgical delay is characterized by an operation waiting time exceeding 24 h. The perforation of the appendix is determined by intraoperative findings. Postoperative complications were classified according to the Clavien–Dindo classification, with only complications of at least grade 3 severity being analyzed in this study.

Statistical analysis

Data were presented as mean ± standard deviation (SD) or median (interquartile range, IQR) for continuous variables, and frequency (percentage) for categorical variables. In univariate analysis, the differences in the distributions of continuous variables and categorical variables between two groups were examined using the Student t test, Mann–Whitney U test, Wilcoxon rank-sum test, Chi-square test, and Fisher’s exact test as appropriate. Multivariate analysis was conducted by fitting a logistic regression model to estimate the adjusted effects of risk factors or predictors on outcome. Two-sided p value ≤ 0.05 was considered statistically significant. All statistical analysis was performed using the R 4.2.2 software (R Foundation for Statistical Computing, Vienna, Austria).

Results

Patient characteristics

A total of 2158 patients underwent appendectomy because of acute appendicitis between January 2014 and June 2018. The baseline patient characteristics in the regional hospital group (N = 1223) and the tertiary care hospital group (N = 935) are presented in Table 1. Patients in regional hospital group had higher body mass index (24.0 vs. 23.5, p < 0.001); more use of cigarette (28.7 vs. 18.8%, p < 0.001), alcohol (17.2 vs. 8.7%, p < 0.001), and betel nut (8.8% vs. 2.7%, p < 0.001); more patients with WBC count greater than 20 k (/µL) (9.3 vs. 6.7%, p = 0.031); however, patients in the tertiary care hospital group had more college degree (68.9 vs. 43.8%, p < 0.001), pregnancy (1 vs. 0.2%, p = 0.026), and coronary artery disease (1.3 vs. 0.4%, p = 0.023). There were no significant differences of age, sex, and other preoperative characteristics between the two groups. Regarding surgical methods, laparoscopic appendectomy has been the standard procedure for over a decade. Of the 2158 patients, 98.1% underwent laparoscopic method, and 1.9% had open procedures. In the care hospital group, 2.6% had open surgeries, compared to 1.5% in the regional hospital group.

Table 1 Comparisons of preoperative characteristics between patients operated in the regional hospital group and tertiary care hospital group
Full size table

Perioperative outcomes

The comparison of perioperative outcomes of the patients in regional hospital group and tertiary care hospital group are shown in Table 2. Preoperatively, there were significant more patients with delay diagnosis in the regional hospital group (5.3 vs. 3.3%, p = 0.026). The mean waiting time from triage until surgery was significantly shorter in regional hospital group (12.0 vs. 17.3 h, p < 0.001). Significant more patients experienced a surgical delay more than 24 h (15.7 vs. 7.6%, p < 0.001) and midnight operation (27.7 vs. 21.6%, p = 0.001) in the tertiary care hospital group than in regional hospital group. The median time of operation was significantly longer in tertiary care hospital group (64 vs. 50 min, p < 0.001), with a higher prevalence of appendix perforation (22.4 vs. 13.3%, p < 0.001). There were more patients with postoperative ICU stay in the regional hospital group (4.4 vs. 2.5%, p = 0.015). The median hospital costs were significantly higher in the tertiary care hospital group (1712 vs 1428 USD, p < 0.001). There was no significant difference of complication rate and postoperative hospital stay between the two groups.

Table 2 Comparison of perioperative outcomes of the patients treated in the regional hospital group and the tertiary care hospital group
Full size table

Factors associated with surgical delay and complications

Four factors for surgical delay were found in univariate analysis, including age, tertiary care hospital, diabetes mellitus, and delay diagnosis (Table 3). In the multivariate logistic regression analysis, diabetes mellitus was not associated with the development of a surgical delay. After adjusting the factors of age, sex, diabetes mellitus, off work time triage, and delay diagnosis, treating in a tertiary care hospital is still a risk factor for surgical delay (OR: 2.94, 95% CI 2.18–4.01, p < 0.001, Table 4). Many factors for postoperative complications were found in univariate analysis, including older age, male sex, lower education, use of cigarette, alcohol, or betel nut, diabetes mellitus, fever at triage, WBC count greater than 20 k (/µL) at triage, surgical delay of more than 24 h, longer operation time, and appendix perforation (Table 5). In the multivariate logistic regression analysis (Table 6), age (OR: 1.027, 95% CI 1.00–1.04, p = 0.013), male sex (OR: 2.382, 95% CI 1.11–5.52, p = 0.031), surgical delay (OR: 2.997, 95% CI 1.30–6.47, p = 0.007), and appendix perforation (OR: 5.619, 95% CI 2.72–11.85, p < 0.001) were association factors of postoperative complications. After adjusting the factors of age, sex, surgical delay, appendix perforation, treating in a tertiary care hospital becomes a protective factor of postoperative complication (OR: 0.449, CI 0.20–0.94, p = 0.041).

Table 3 Comparisons of preoperative characteristics between patients with and without surgery delay exceeding 24 h
Full size table
Table 4 Factors associated with surgical delay using multivariate logistic regression analysis
Full size table
Table 5 Comparisons of characteristics between patients with and without postoperative complications after urgent appendectomy for acute appendicitis
Full size table
Table 6 Preoperative factors associated with postoperative complications using multivariate logistic regression analysis
Full size table

Discussion

The aim of the present study was to compare the surgical outcomes and the quality of care among adult patients undergoing appendectomy for acute appendicitis in tertiary care hospitals versus regional hospitals. Our results showed that patients in tertiary care hospitals required longer surgical waiting time, with more surgical delay of greater than 24 h, and more perforated appendix. The average hospital cost was higher in tertiary care hospital than in regional hospitals.

Patient outcomes are influenced by the entire treatment process, which encompasses administrative efficiency, surgical quality, and medical care quality. While tertiary care hospitals and regional hospitals differ in these areas, this classification merely captures a multitude of intricate factors. Delayed surgery leading to perforation and increased postoperative complications has always been a concern in the treatment of appendicitis patients. The results of different studies on the impact of waiting time are highly variable, with some suggesting that a delay up to 48 h would not have much impact [16,17,18], while majority of studies suggest that delays exceeding 12–24 h would increase risks of perforation and complications [19,20,21,22,23]. A meta-analysis of 11 non-randomized studies also showed that in-hospital delays of 12–24 h in stable patients were not associated with increased risk of perforation [9]. From a conservative standpoint, avoiding surgery delays exceeding 24 h is a reasonable goal and is beneficial for patients with acute appendicitis. Although appendicitis is an abdominal emergency, its symptoms are often similar to those of gastroenteritis or other abdominal discomforts [9, 24]. From seeking medical attention and inspection by a doctor, to laboratory tests and arranging imaging tests, a period of evaluation and making diagnosis is required. For tertiary care hospitals filled with critically ill patients and emergency surgeries, appendicitis patients may be sacrificed invisibly because they are less urgent than other critically ill patients. The reasons for delaying surgery and causing delays are numerous, with the most likely cause being overload of medical services. Emergency surgeries that are life-threatening, such as brain or heart surgery, will be prioritized randomly before appendectomy. In our results, although the proportion of delayed diagnoses was lower in tertiary care hospitals than in regional hospitals, the average surgical wait time was longer, the proportion of delays exceeding 24 h was higher, the proportion of appendix perforation was higher, and the proportion of midnight surgeries was higher, all of which corroborate these findings.

In addition to tertiary care hospitals, other factors that cause surgical delays include delayed diagnosis and older age. It is not surprising that a delayed diagnosis inherently prolongs the timeline from triage to surgical intervention. Surgical delay for appendicitis in older patients may be attributed to multiple factors: the necessity of additional time to optimize the patient's overall health status prior to surgery, extended deliberation periods for patients and their families to reach informed decisions, and a potential reluctance among surgeons to operate on older patients during non-daylight hours. While our findings showed prolonged surgical waiting times and increased surgical delays in tertiary care hospitals, we observed more postoperative ICU stays in regional hospitals. This discrepancy may be attributed to the differential ICU bed allocation between the two settings. In particular, regional hospitals, typically serving fewer critically ill patients, often have greater ICU bed availability. This abundance leads to more lenient postoperative ICU admission criteria compared to tertiary care hospitals.

Surgical complications are an important issue for patients undergoing appendectomy. Our study found that the occurrence of complications was related to age, male sex, delayed surgery, and perforated appendix, but not related to tertiary care hospital. Age [5, 6], male sex [7], and diabetes [8] have been reported as risk factors for complications in the literature. Tertiary care hospital has never been reported as a risk factor for complications in appendectomy surgery. While tertiary care hospital was an independent risk factor for delayed surgery in this study, it appears to be a protective factor for complications. This suggests that the medical care provided by tertiary care hospitals might be better than that provided by regional hospitals. However, if surgery is delayed for more than 24 h due to various possible factors, the delay itself increases the risk of complications.

Tertiary care hospitals differ from regional hospitals in that they have many surgical residents who are still in training, and therefore, it is more likely that surgery performed during the night is carried out by these residents. This fact may explain the longer average surgical times at tertiary care hospitals compared to regional hospitals. Our results also show that there are some inherent differences between the patient populations at tertiary care hospitals and regional hospitals, such as education level and substance use habits, including smoking, alcohol use, and betel nut consumption, as well as personal medical history, among others. These differences may be due to regional urban–rural disparities or selection bias, as patients with more complex medical histories or worse health conditions may be more inclined to seek treatment at tertiary care hospitals. As the elderly and those with complex diseases are increasingly prevalent in today's society, tertiary care hospitals theoretically have an advantage in treating these patient populations due to their new equipment and multidisciplinary care teams. However, tertiary care hospitals also have disadvantages, such as having more critically ill patients, being busier, and having longer surgical waiting times and delays exceeding 24 h. Overall, based on the results of our study, we suggest that younger patients with less complex medical histories who require appendectomy surgery may receive treatment at regional hospitals to reduce surgical waiting times, delays, and medical costs. Tertiary care hospitals could be reserved for patients with more complex diseases or older patients with appendicitis. Therefore, for adult patients with less complex medical histories diagnosed with appendicitis at a tertiary care hospital, establishing an efficient referral system to seamlessly redirect them to a regional hospital for urgent surgery without delays might enhance their quality of care, especially during busy times.

Our study has several limitations. Firstly, it is a retrospective study that is limited to a specific region and a single ethnicity of patients from three hospitals. Secondly, we only examined surgical patients and did not consider non-surgical treatment of appendicitis patients. However, our study benefits from a significant sample size and investigates a topic that has previously been understudied by comparing the differences in perioperative outcome between tertiary care hospitals and regional hospitals in treating adult appendicitis patients.

Conclusion

In summary, patients who undergo appendectomy in regional hospitals experience shorter wait times and fewer surgical delays exceeding 24 h than those treated in tertiary care hospitals. Tertiary care hospitals could consider to establish effective referral systems to direct patients with simpler medical histories to regional hospitals, to enhance the quality of patient care and outcomes, while also reducing medical expenses.