ABSTRACT

Objective:

Obesity is a major public health issue worldwide. Obesity, along with its associated comorbidities, may impact surgical outcomes. Obesity is linked to wound infection, thromboembolic complications, and respiratory difficulties in surgical patients. Obesity may or may not have a negative impact on postoperative outcomes.

Methods:

Patients over the age of 18 who had endometrial cancer surgery were screened retrospectively. Patient data from the hospital database were retrieved in terms of demographics, comorbidities, American Society of Anesthesiologists (ASA) score, Charlson Comorbidity index (CCI) score, duration of operation and anesthesia, postoperative intensive care admission, complications, and length of hospital stay. They were also reviewed and recorded from the patient file.

Results:

The subjects’ mean age was 57.2±9.8 years (range: 31-84 years). In patients with endometrial cancer, American Society of Anesthesiologist (ASA) (p=0.001), Charlson Comorbidity Index (CCI) (p=0.001) scores, operation time, postoperative complication risk (p=0.004), and hospital stay increase (p=0.029) as we progress from the normal group to the obese and morbidly obese groups.

Conclusion:

Obesity increases the risk of postoperative complications such as wound infection, sepsis, acute renal damage, evisceration, and hospital stay in patients who have had endometrial cancer surgery. The ASA and CCI scores were related to postoperative complications, with the CCI score also being related to the length of hospital stay. The fact that these scores provide information about the postoperative outcomes of patients from the preoperative period emphasizes the significance of these scores once more.

INTRODUCTION

Obesity is a major public health issue worldwide (1,2). Endometrial cancer, one of the most common cancers worldwide, is strongly linked to obesity (3,4). Endometrial cancer is primarily treated through surgery (5). Obesity, along with its associated comorbidities, is thought to impact surgical outcomes. Obesity is associated with wound infection, thromboembolic problems, and respiratory problems in patients undergoing surgery, but whether obesity causes a negative postoperative outcome is debatable (6,7). As a result, studying the effect of obesity on postoperative outcomes is critical for predicting morbidity and hospital stay in patients undergoing surgery. Because of the numerous comorbid diseases that accompany obese patients, a practical preoperative evaluation is essential (8,9).

For more than sixty years, the American Society of Anesthesiologists (ASA) score has been the most commonly used score for preoperative patient evaluation by anesthesiologists. When combined with other factors (for example, the type of surgery), the score, which was last updated in 2020, is extremely useful in estimating perioperative risk (10). Obese patients [body mass index (BMI); 30-40] with no other comorbidities, for example, were classified as ASA-II; morbidly obese patients (BMI>40)were classified as ASA-III. In other words, according to the ASA score, the presence/increase of obesity alone raises the perioperative risk. However, the ability of this score to predict postoperative risk is unclear. The management of obese patients is difficult because of accompanying metabolic dysfunction, impaired glucose intolerance, and respiratory and cardiovascular diseases (11).

The Charlson Comorbidity index (CCI) was developed to assess the one-year mortality risk by allocating specific points to each of the seventeen comorbidities (12). CCI is a simple and easily applicable method for estimating the risk of death from comorbid disease (13). This index was later adapted for use with the International Classification of Diseases nine and ten, and it was used to estimate mortality (14,15). There are also studies on the use of CCI to predict postoperative outcomes in the literature (16,17). Obesity is not listed as a risk factor in CCI. Obesity, on the other hand, can be accompanied by diseases such as diabetes mellitus and stroke. In studies, the accuracy of the hypothesis is that as obesity increases, so do comorbid disorders and, consequently, CCI has not been fully clarified (18). CCI studies in obese patients are also important in testing this hypothesis.

The purpose of this retrospective study was to assess the effect of obesity on postoperative complications in endometrial cancer patients, including the role of two commonly used scoring systems (ASA, CCI) in predicting postoperative complications.

METHODS

Bakırköy Dr. Sadi Konuk Training and Research Hospital Ethics Committee approval was obtained (protocol no: 2020/221, date: 08.06.2020). Patients over the age of 18 who had endometrial cancer surgery between January 2018 and April 2020 were screened retrospectively. Demographic information, comorbidities, ASA score, CCI score, duration of operation, duration of anesthesia, hospitalization in the postoperative intensive care unit (ICU), complications, and length of hospital stay of patients included in the study. In terms of time, patient data were analyzed and recorded from the hospital database and patient file. Patients who presented to the gynecological oncology clinic with the diagnosis of endometrial cancer were also included. Patients with missing data were barred from participation in the study.

All patients undergoing endometrial ca are subjected to a standard anesthesia protocol developed in our clinic. Patients who undergo a preoperative anesthesia examination have detailed physical examination and laboratory results, ASA scores based on comorbidities, and anesthesia risks recorded. The ASA standard (electrocardiogram, peripheral oxygen saturation, and non-invasive blood pressure) is used to monitor each patient brought into the operating room. An infusion of 4-6 mL/kg/h crystalloid fluid is initiated, and antibiotic therapy is initiated. Following anesthesia induction with 2 mcg/kg iv fentanyl, 2-3 mg/kg propofol, and 0.6 mg/kg rocuronium, patients are intubated and connected to the anesthesia device in volume control mode. The tidal volume is 6-8 mL/kg, and the respiratory frequency is 12 beats per minute. End-tidal CO₂ is adjusted to stay between 35 and 45 mmHg. For anesthesia maintenance, sevoflurane (MAC 0.8-1) and remifentanil (0.05-0.2 mcg/kg/min) are used. When the surgical field was being closed, the patients were given paracetamol 1 g and tramadol 1 mg/kg iv as analgesics. In the postoperative recovery room, patients with numerical rating scale pain scores greater than 4 are given pethidine hydrochloride 0.3 mg/kg as rescue analgesia.

The need for postoperative intensive care is assessed following the operation, and admission to the ICU is determined based on the patients’ comorbidities, the preoperative hemodynamic course, respiratory distress, and the need for vasopressor/inotrope. Patients whose general condition and hemodynamics are stable are extubated and taken to the recovery room. Patients who have a modified Aldrete score of more than 8 in their follow-up are referred to the service.

Statistical Analysis

Data were analyzed using SPSS 20 for Windows (IBM Corp., Armonk, NY, USA). The normal distribution of the data was evaluated using the Kolmogorov-Smirnov test. The normally distributed variables were presented as the mean ± standard deviation, while the non-normally distributed variables were presented as the median (interquartile range: 25-75 percentiles). Categorical variables were presented as numbers and percentages. ANOVA test (post-hoc: Bonferroni correction) was used for the group comparison of the normally distributed variables and the Kruskal-Wallis H test (post-hoc: Dunn’s correction) was used for the intergroup comparison of the non-normally distributed variables. The chi-square and Fisher Exact tests were used for the intergroup comparison of the categorical variables. Possible risk factors for developing postoperative complications were determined by Cox regression analysis. Variables related to operation time and complication development time were analyzed by Spearman correlation analysis. P<0.05 was accepted as statistically significant.

RESULTS

The mean age of the subjects was 57.2±9.8 years (range: 31-84 years), and BMI was 35.1±8.8 kg/m². According to ASA classification the percentage of ASA II patients’ were 54.7% (n=70) and ASA III patients’ were 45.3% (n=58). In addition, 35.9% of patients had normal BMI levels. While 32.8% patients were obese, 31.3% were morbidly obese. Comorbidities were present in 67.2% of the patients. Postoperative complications developed in 16.4% of the patients. The median length of hospital stay was five days, and the mortality rate was 1.6%. The comorbidity ratio and ASA-III rate ratio were higher in the morbid obese group compared to the other groups. The highest value of median CCI scores was in the morbid obesity group. The complication ratio was higher in the morbid obese group than in the other groups, and higher in the obese group than the normal weight. The duration of hospital stay was longer in the morbid obese group compared to the other groups, while it was similar in the obese group and normal weight (Table 1).

Table 1

The factors associated with the risk of complications are shown in Table 2. Increased BMI, morbid obesity, the presence of respiratory diseases, ASA-III score, increased duration of operation, and hospitalization in the ICU are associated with the risk complications (Table 2). In the regression model, including all risk factors, the independent risk factors that increased the risk of complications were morbid obesity [hazard ratio (HR)= 6.03, p=0.008] and hospitalization in ICU (HR=10.2, p=0.001). A positive correlation was found between BMI level and length of hospital stay (r=0.336, p=0.007), and a negative correlation was found between the time of complication development (r=-0.328, p=0.013) (Table 3).

Table 2

Table 3

Compared with the normal BMI group, ASA (p<0.001) and CCI (p<0.001) scores, operation time, length of hospital stay (p=0.029) and postoperative complication risk (p=0.004) were increased in the obese and morbidly obese patient group.

DISCUSSION

The current study assessed the effect of obesity on postoperative complications in patients undergoing endometrial cancer surgery, as well as the ability of ASA, CCI, one of the widely used scoring systems, to predict postoperative outcome. Our secondary goal was to assess the impact of obesity on these patients’ length of hospital stay and the ability of the scores to indicate this.

In our study, it was found that as BMI increased in patients with endometrial cancer, the rate of comorbidity increased (p=0.005), the CCI score increased (p<0.001) and the length of hospital stay was prolonged. Obesity is associated with a number of comorbid diseases, independent of endometrial cancer. Insulin resistance, type 2 diabetes mellitus, hypertension, dyslipidemia, cardiovascular disease, stroke and sleep apnea are the most serious ones (19,20). In our study, we observed a significant increase in hypertension, diabetes and respiratory tract diseases as BMI increased (p<0.05). While the presence of respiratory tract diseases increased the risk of postoperative complications in our patients (p<0.05), the presence of diabetes mellitus and hypertension did not increase the risk of complications. In addition to the increase in comorbid diseases seen in obese patients, chronic inflammation and dysmetabolism have been shown to adversely affect postoperative outcomes (7,21). However, there are also studies stating that the risk of complications (22) and mortality (23,24) is significantly lower in obese patients as an obesity paradox. In addition to obesity, it has been shown that the risk of postoperative complications is higher in patients with high ASA and CCI, long operative time and preoperative respiratory disorders (25-29). In our study, it has been shown that the ASA scores of the patients are high, CCI scores increase as BMI increases (p<0.05), the operation time is longer (p<0.05) and the need for ICU hospitalization is higher, supporting the literature. These scores and associated comorbid diseases explain the relationship between scores and postoperative complications as obesity rises. From the preoperative period, these two scores must predict the postoperative outcome. In our study, while the increase in CCI score was associated with the length of hospital stay (p<0.05), the same correlation was not found in the ASA score. We think that this may be due to the study population being limited to ASA-II and III patients. There are studies in the literature supporting the prognostic importance of CCI in terms of postoperative complications. Our study results were in agreement with the results of previous studies in predicting the postoperative outcome of obesity and CCI by cross-sectional design (30,31). A study of patients undergoing radical cystectomy found that demographic factors and comorbidity indices such as ASA, BMI, and CCI had poor discriminating ability for adverse events (sepsis, wound infection, hospitalization, and prolonged hospital stay) (32). The ASA independently estimated the duration of surgery, length of hospital stay, and hospital cost in a study of total knee arthroplasty patients; BMI has been associated with intraoperative time (33). According to the findings of this study, there is no statistically significant increase in postoperative intensive care admissions as we approach the morbidly obese group. However, as one progresses from the normal BMI group to the obese and morbidly obese groups, the hospitalization rate in the postoperative ICU increases by 4.3, 11.9, and 15.0 percent, respectively. As a result, it is expected that increasing the number of patients in the groups will result in statistical significance. In our study, the factors affecting the length of hospital stay were found to be age, BMI, CCI score, and operation time. In direct proportion to the increase in these factors, the length of stay in the hospital also increased.

Study Limitations

The number of patients in the groups was insufficient because of the retrospective nature of the presented study. Furthermore, whether the patients’ operations were performed laparoscopically or openly may have affected postoperative complications and hospital stay, but this was not investigated in our study.

CONCLUSION

Obesity increases the risk of postoperative complications such as wound infection, sepsis, acute renal damage, evisceration, and hospital stay in patients who have had endometrial cancer surgery. Obesity is an effective risk factor for developing endometrial cancer, and it is associated with a poor postoperative outcome in patients who have this cancer and have undergone surgery. Furthermore, in our study, ASA and CCI scores were linked to postoperative complications. Simultaneously, the CCI score was linked to the length of hospital stay. The fact that these scores, which are widely used in routine practice, provide us with information about patients’ postoperative outcomes from the preoperative period emphasizes the importance of these scores once more.

ETHICS

Ethics Committee Approval: Bakırköy Dr. Sadi Konuk Training and Research Hospital Ethics Committee approval was obtained (proctocol no:2020/221, date: 08.06.2020).

Informed Consent: This was a retrospective study.

Authorship Contributions

Surgical and Medical Practices: G.Ö.Y, G.S., Concept: G.Ö.Y., G.S., F.T., D.A., Design: G.Ö.Y., G.S., F.T., D.A., Data Collection or Processing: D.A., Literature Search: G.S., F.T., Writing: G.Ö.Y., G.S., F.T., D.A.

Conflict of interest: No conflict of interest was declared by the authors.

Financial Disclosure: The authors declared that this study received no financial support.

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The Effect of Comorbidities and Obesity on Postoperative Outcomes