Evaluating risk factors for surgical site infections and the effectiveness of prophylactic antibiotics in patients undergoing laparoscopic cholecystectomy

Abstract

BACKGROUND

Surgical site infections (SSIs) are a significant complication in laparoscopic cholecystectomy (LC), affecting patient outcomes and healthcare costs.

AIM

To identify risk factors associated with SSIs and evaluate the effectiveness of prophylactic antibiotics in reducing these infections.

METHODS

A comprehensive retrospective evaluation was conducted on 400 patients who underwent LC from January 2022 to January 2024. Patients were divided into infected (n = 36) and non-infected (n = 364) groups based on the occurrence of SSIs. Data collected included age, diabetes mellitus status, use of prophylactic antibiotics, and specific surgical complications. Statistical analyses using SPSS (Version 27.0) involved univariate and multivariate logistic regression to determine factors influencing the risk of SSIs.

RESULTS

The use of prophylactic antibiotics significantly reduced the incidence of SSIs (χ² = 68.34, P < 0.01). Older age (≥ 60 years) and comorbidities such as diabetes mellitus were identified as significant risk factors. Surgical complications like insufficient cystic duct stump, gallbladder perforation, and empyema also increased SSI risk. Notably, factors such as intraoperative blood loss and operation time did not significantly impact SSI occurrence.

CONCLUSION

Prophylactic antibiotics are effective in reducing the risk of SSIs in patients undergoing LC. Age, diabetes mellitus, and certain surgical complications significantly contribute to the risk. Effective management of these risk factors is essential to improve surgical outcomes and reduce the incidence of SSIs.

Key Words: Surgical site infections; Laparoscopic cholecystectomy; Prophylactic antibiotics; Risk factors; Surgical outcomes

Core Tip: This study addresses the significant challenge of surgical site infections in laparoscopic cholecystectomy, highlighting critical risk factors and the role of prophylactic antibiotics in reducing these infections. Our comprehensive retrospective analysis of 400 patients offers vital insights into the prevention and management strategies that can be employed to minimize surgical site infections, thereby enhancing patient outcomes and reducing healthcare costs. The robustness of our statistical analysis and the practical implications of our findings make this study a valuable contribution to the field of surgical research.

INTRODUCTION

Laparoscopic cholecystectomy (LC) has established itself as the gold standard for gallbladder removal, owing to its less invasive characteristics, diminished postoperative discomfort, abbreviated hospitalizations, and expedited recovery periods relative to open cholecystectomy[1]. Despite its extensive utilization and general safety, LC is not devoid of problems. Surgical site infections (SSIs) continue to pose a substantial issue, impacting patient outcomes and healthcare expenditures. SSIs are prevalent healthcare-associated infections that arise postoperatively at the surgical site. These infections may vary from superficial dermal infections to more severe infections affecting subcutaneous tissues, organs, or implanted materials[2,3]. SSIs correlate with heightened morbidity, extended hospitalizations, supplementary surgical interventions, and escalated healthcare expenditures[4,5]. Comprehending the risk variables linked to SSIs is essential for formulating effective prevention strategies.

Multiple risk factors for SSIs have been discovered in individuals receiving LC. These factors can be classified into patient-related, procedure-related, and environmental categories. Factors associated to the patient encompass age, obesity, diabetes mellitus, immunosuppression, and the existence of concomitant conditions[6,7]. Procedure-related parameters encompass the duration of surgery, the surgeon’s level of experience, the utilization of drains, and the intricacy of the surgical intervention. Environmental considerations include operating room settings, such as sterilization methods and the surgical team’s compliance with aseptic techniques. A crucial strategy to avert SSIs is the administration of prophylactic antibiotics[8,9]. Prophylactic antibiotics are provided to patients prior to, during, and following surgery to mitigate the risk of infections. Their application is to reduce the microbial load in the surgical area, thereby reducing infection onset[10,11].

Current debates on the use of prophylactic antibiotics, particularly for low-risk patients, are underscored by contrasting findings in recent studies. Carey et al[12] highlighted the elevated risk of severe infections in patients with diabetes, suggesting a potential need for tailored antibiotic strategies based on diabetic status and type. In contrast, Ko et al[13] observed no significant benefit from perioperative antibiotic use in carpal tunnel release surgeries, even in diabetic patients, though a trend towards benefit was noted in those with uncontrolled diabetes. The objective of this study is to evaluate the risk factors associated with SSIs in patients undergoing LC and to assess the effectiveness of prophylactic antibiotics in preventing these infections. By identifying the key risk factors, this study aims to provide insights into targeted interventions that can reduce the incidence of SSIs.

MATERIALS AND METHODS

Study design

A retrospective analysis was conducted at our institution to determine the risk factors for SSIs and evaluate the efficacy of prophylactic antibiotics in patients having LC. This study covered the period from January 2022 to January 2024. This study comprised a total of 400 individuals who underwent LC. Among them, 36 patients acquired SSIs postoperatively and were categorized into the infection group. The remaining 364 patients did not experience SSIs and were categorized in the non-infection group. All participants in the study provided informed consent. The ethics committee of our hospital painstakingly evaluated and approved the research methodology, objectives, and protocols.

Inclusion and exclusion criteria

Patients undergoing LC within the specified study period (January 2022 to January 2024) were included if they were aged 18 years and older, provided informed consent for participation, and had comprehensive medical records and follow-up data available for analysis. Patients were excluded if their LC was converted to an open cholecystectomy during the procedure, if they had active infections or SSIs prior to the LC, if they had known immunodeficiency disorders or were on long-term immunosuppressive therapy, or if they underwent emergency LC to maintain a homogeneous study population. To minimize confounding factors and maintain homogeneity, the following exclusion criteria were applied: These criteria were critical to ensuring a study cohort conducive to accurately evaluating the impact of prophylactic antibiotics on the prevention of SSIs in LC.

Data collection

We collected comprehensive patient data to identify factors potentially contributing to surgical outcomes. The information gathered included the use of prophylactic antibiotics, intraoperative blood loss (≥ 100 mL), age (≥ 60 years), hospital stay (> 5 days), body mass index (≥ 25 kg/m²), operation time (≥ 1 hour), anemia, diabetes mellitus, insufficient cystic duct stump, gallbladder perforation, gallbladder empyema, and postoperative hematoma. The rationale behind selecting these variables was to comprehensively assess a multitude of factors that could potentially influence surgical and post-surgical outcomes, particularly the incidence of SSIs. In the protocol for prophylactic antibiotic administration, all patients assigned to receive antibiotics were administered a single dose of intravenous cefazolin (1 g) within 30 minutes prior to the surgical incision. This choice is aligned with clinical guidelines recommending cefazolin due to its efficacy against common pathogens involved in SSIs in abdominal surgeries. Missing data were managed by excluding any patient records with incomplete critical information, ensuring that all analyzed cases had comprehensive and reliable data. Specifically, patients with incomplete follow-up data, insufficient medical records, or missing essential variables such as the use of prophylactic antibiotics were excluded from the final analysis. This approach minimized potential biases arising from incomplete datasets, and we verified that the proportion of missing data was minimal and unlikely to affect the study outcomes significantly. Data collection adhered to ethical standards to ensure accuracy and reliability in the subsequent analyses.

Statistical analysis

Statistical analyses were rigorously conducted using SPSS software (version 27.0). Initially, data were categorized as either quantitative or categorical, with normality tests applied to determine their distribution. Quantitative data following a normal distribution were analyzed using independent sample t-tests to assess inter-group statistical significance, with results expressed as mean ± SD. For quantitative data not normally distributed, medians and interquartile ranges M[P25, P75] were used for representation, and the Mann-Whitney U test was utilized for group comparisons. Categorical data were summarized as frequencies and percentages, and the χ² test was employed to analyze independence or associations among these variables. To control for potential confounding factors, variables demonstrating significant associations with the occurrence of SSIs in univariate analysis were further analyzed through multivariate logistic regression. This advanced statistical approach allowed us to adjust for confounding variables, such as age, diabetes mellitus, and specific surgical complications, providing a more definitive understanding of their independent impact on infection risks. This method enabled the calculation of odds ratios and confidence intervals, thus offering a comprehensive view of the contributory factors affecting SSIs. All hypotheses were tested using two-tailed analyses, with a P value of less than 0.05 considered indicative of statistical significance.

RESULTS

Univariate analysis of factors influencing SSIs in LC

The univariate analysis conducted to identify risk factors for SSIs in patients undergoing LC highlighted several significant associations. Age was another significant factor, with older patients (≥ 60 years) more frequently affected by SSIs. Specifically, 55.6% of infected patients were older than 60, compared to only 27.7% in the non-infected group, indicating a clear age-related vulnerability (χ² = 10.72, P < 0.01). Other clinical variables that showed a statistically significant association with SSIs included diabetes mellitus, conditions related to surgical technique such as insufficient cystic duct stump, gallbladder perforation, gallbladder empyema, and postoperative hematoma. Each of these factors had a markedly higher prevalence in the infected group, all correlating with increased risks of developing SSIs (P < 0.01 for each) (Table 1).

Table 1 Univariate analysis of factors associated with surgical site infections in patients undergoing laparoscopic cholecystectomy.

Factors	Infected (n = 36)	Non-infected (n = 364)	χ²	P value
Prophylactic antibiotics use, n (%)	13 (36.1)	326 (89.6)	68.34	< 0.01
Intraoperative blood loss (≥ 100 mL), n (%)	14 (38.9)	146 (40.1)	0	1
Age (≥ 60 years), n (%)	20 (55.6)	101 (27.7)	10.72	< 0.01
Hospital stay (> 5 days), n (%)	11 (30.6)	98 (26.9)	0.07	0.79
Body mass index (≥ 25 kg/m²), n (%)	15 (41.7)	168 (46.2)	0.12	0.73
Operation time (≥ 1 hours), n (%)	12 (33.3)	118 (32.4)	0	1
Anemia, n (%)	10 (27.8)	58 (15.9)	2.47	0.12
Diabetes mellitus, n (%)	15 (41.7)	69 (19.0)	8.86	< 0.01
Insufficient cystic duct stump, n (%)	16 (44.4)	36 (9.90)	31.6	< 0.01
Gallbladder perforation, n (%)	17 (47.2)	53 (14.6)	22	< 0.01
Gallbladder empyema, n (%)	19 (52.8)	61 (16.8)	24.36	< 0.01
Postoperative hematoma, n (%)	13 (36.1)	28 (7.7)	25.75	< 0.01

Factors like intraoperative blood loss, hospital stay, body mass index, and operation time did not show a statistically significant impact on the likelihood of developing SSIs. This suggests that while operative conditions are essential, they might not be as predictive of SSIs as the patient’s health status and specific procedural complications. Anemia, although more common among infected individuals, did not reach a level of statistical significance to be considered a robust predictor of infection risk (χ² = 2.47, P = 0.12).

Multivariate logistic regression analysis of factors influencing SSIs in LC

This study employed multivariate logistic regression to examine the influence of various factors on the risk of SSIs following LC. Key findings from this analysis are presented in terms of their OR, Wald statistics, and associated P values to ascertain the significance and strength of each predictor. Age also played a crucial role, with patients aged 60 years or older being significantly more likely to develop SSIs, as reflected by an odds ratio (OR) of 3.702 [95% confidence interval (CI): 1.311-4.545, P = 0.044). Diabetes Mellitus further compounded the risk, with an odds ratio of 2.599 (95%CI: 1.110-3.950, P = 0.018), indicating that diabetic patients are more susceptible to postoperative infections (Table 2).

Table 2 Multivariate logistic regression analysis of factors associated with surgical site infections in patients undergoing laparoscopic cholecystectomy.

Factors	β	Standard error	Wald	OR	95%CI for OR	P value
Prophylactic use of antibiotics	-0.365	1.504	4.17	0.694	0.650-0.740	0.008
Age (≥ 60 years)	0.328	1.275	3.89	3.702	1.311-4.545	0.044
Diabetes mellitus	0.237	1.095	2.798	2.599	1.110-3.950	0.018
Insufficient cystic duct stump	0.361	1.392	4.053	3.865	1.345-4.900	0.026
Gallbladder perforation	0.280	1.015	3.457	3.150	1.125-4.295	0.043
Gallbladder empyema	0.291	1.288	3.270	3.055	1.118-4.135	0.011
Postoperative hematoma	0.235	1.215	2.735	2.575	1.030-3.750	0.029

OR: Odds ratio; CI: Confidence interval.

Technical factors during surgery such as an insufficient cystic duct stump, gallbladder perforation, and gallbladder empyema were also significant predictors. These factors showed increased odds of infections, with ORs of 3.865, 3.150, and 3.055 respectively, all indicating heightened risk associated with these complications. Postoperative hematoma was another significant risk factor with an OR of 2.575 (95%CI: 1.030-3.750, P = 0.029) (Table 2). These results underscore the importance of vigilant surgical practices and careful management of patient comorbidities to mitigate the risk of SSIs following LC. Prophylactic antibiotics remain a critical component of infection control strategies in this patient population.

Impact of prophylactic antibiotics on SSIs in LC

The prophylactic use of antibiotics in LC has shown a marked impact on reducing SSIs, a critical component of postoperative care. The data reveals that the administration of antibiotics was significantly lower in the infected group (36.1%) compared to the non-infected group (89.6%), strongly indicating that prophylactic antibiotics significantly reduce the risk of SSIs (χ² = 68.34, P < 0.01, Table 1). Multivariate logistic regression further confirmed this, showing a protective β value of -0.365 and an OR of 0.694, which statistically supports the beneficial effect of antibiotic use in preventing infections (95%CI: 0.650-0.740, P = 0.008, Table 2). These findings underscore the necessity of integrating prophylactic antibiotic protocols into the surgical regimen for patients undergoing LC, particularly for those identified as high-risk based on other underlying factors.

DISCUSSION

SSIs present a considerable issue in LC, impacting patient outcomes, extending hospital stays, and elevating healthcare expenses. Comprehending the risk factors linked to SSIs and assessing the efficacy of prophylactic antibiotics are essential for enhancing surgical safety and patient care. Prophylactic antibiotics, given before to incision, have been thoroughly investigated for their ability to prevent infections by diminishing the microbial load at the surgical site[14,15]. However, the debate continues regarding their routine use in LC, particularly given the procedure’s minimally invasive nature and generally low risk of infection compared to open surgeries. The focus of this discussion revolves around the multifactorial nature of SSIs, which include patient-related factors such as age and comorbidities (e.g., diabetes mellitus), and procedure-specific variables such as operative time and technical complications like gallbladder perforation or insufficient cystic duct stump[16,17]. The discourse persists concerning their habitual application in LC, especially considering the procedure’s minimally invasive characteristics and comparatively low infection risk relative to open operations. This discussion centers on the multifactorial nature of SSIs, encompassing patient-related factors such as age and comorbidities (e.g., diabetes mellitus), as well as procedure-specific variables including operative duration and technical complications like gallbladder perforation or inadequate cystic duct stump[18,19]. Each of these factors can separately or collectively elevate the risk of postoperative infections. This work seeks to analyze these interactions and offer evidence-based recommendations for the preventive use of antibiotics, considering their advantages in relation to the risks of antibiotic resistance and other possible consequences. The results herein enhance the comprehension of optimal management and mitigation of risk variables associated with SSIs in LC, ensuring that preventative interventions are both prudent and efficacious.

The results of this study elucidate several pivotal risk factors that predispose patients to SSIs following LC, with notable implications for both clinical practice and patient management strategies. The significant reduction in SSIs associated with prophylactic antibiotic use highlights the crucial role of timely and appropriate antimicrobial prophylaxis in preventing postoperative infections. The efficacy of prophylactic antibiotics can be attributed to their ability to reduce bacterial colonization at the surgical site, thereby minimizing the potential for pathogenic invasion during and immediately after surgical procedures[20-22]. The heightened risk of SSIs in older patients (≥ 60 years) observed in our analysis may be explained by the physiological changes and comorbid conditions commonly associated with aging, such as diminished immune response and reduced physiological reserve. These factors can impair wound healing and increase vulnerability to infections[23]. This demographic trend underscores the need for tailored perioperative care protocols that address the specific risks associated with elderly patients.

Diabetes mellitus has emerged as a notable risk factor for SSIs. The hyperglycemic condition in diabetic individuals is recognized to disrupt normal immunological processes, such as neutrophil activity, chemotaxis, and phagocytosis. Additionally, the microvascular and macrovascular issues linked to diabetes may hinder blood flow to the surgical site, hence exacerbating healing impairment and elevating infection risks[10,24]. Consequently, rigorous glycemic management throughout the perioperative period is crucial to reduce this risk. The surgical technicalities, including an inadequate cystic duct stump, gallbladder perforation, and gallbladder empyema, were associated with elevated infection rates[25,26]. These difficulties may result in the leakage of bile and potentially gallstones into the peritoneal cavity, so augmenting the bacterial load and eliciting inflammatory responses that can exacerbate the postoperative course. These technological constraints underscore the necessity of precise surgical technique and maybe preoperative imaging or planning to recognize and address any anatomical complications.

The correlation between postoperative hematoma and elevated infection rates can be attributed to the potential of hematomas to act as a culture medium for bacteria. Blood clots can diminish local oxygen levels and impede immune cell function, both essential for infection prevention and treatment. Consequently, meticulous hemostasis during surgery, together with measures to reduce bleeding tendencies in the perioperative phase, is essential[27,28]. The study results necessitate a reevaluation of existing protocols on the treatment of risk factors in LC. The significant protective impact of prophylactic antibiotics indicates that their careful application should be prioritized in clinical procedures, particularly for patients deemed high risk due to age, diabetes, or expected surgical difficulties[29]. The results support a multidisciplinary approach to perioperative care, incorporating the knowledge of surgeons, anesthesiologists, and diabetes specialists to enhance patient outcomes. This collaboration is essential for managing older and diabetic patients, since personalized care regimens can markedly decrease the occurrence of SSIs.

In our analysis, intraoperative blood loss and operation time showed no significant impact on SSIs in LC. This might be attributed to the minimal variation in these factors due to the standardized nature of laparoscopic procedures, which typically involve less blood loss and shorter durations compared to open surgeries. Moreover, the stringent aseptic techniques and controlled environments characteristic of these surgeries likely reduce the potential influence of these factors on infection risks. Additionally, the effective use of prophylactic antibiotics could have mitigated any associated risks, contributing to their non-significant influence in our study. Caroff et al[30] highlight lower SSI rates with laparoscopic vs open colon surgery, mirroring our findings on the efficacy of laparoscopic techniques in cholecystectomy. We build on this by quantifying the role of prophylactic antibiotics, providing a broader evaluation of infection prevention in laparoscopic procedures. Dhole et al’s review of antibiotic prophylaxis confirms its significance in reducing SSIs, a point our research supports with added focus on LC[31]. We further this by detailing how prophylactic antibiotics differentially impact patients with various comorbidities, enriching the strategy for antibiotic use. Woods et al[32] develop a predictive model for SSIs based on pre- and peri-operative factors, akin to our method of identifying risk factors in LC. Our study tailors this model specifically to laparoscopic procedures, improving predictive accuracy and preventive strategies for this surgery type.

This study is not without its limitations. This retrospective nature may lead to selection bias, as it relies on historical data, which can sometimes be incomplete or inconsistent. This limitation restricts our ability to establish causality between observed factors and SSIs, highlighting a need for cautious interpretation of the findings. Additionally, the study’s single-center setting limits its generalizability, as the patient population, surgical protocols, and healthcare practices may differ significantly from those at other institutions. Future studies should also explore routine preoperative screenings, tailored prophylactic antibiotics, and specialized surgical training to mitigate common complications. Incorporating vigilant postoperative monitoring into clinical guidelines could systematically reduce SSIs and enhance safety in LC.

CONCLUSION

The study underscores that age ≥ 60 years, diabetes mellitus, surgical complications such as insufficient cystic duct stump, gallbladder perforation, empyema, and postoperative hematoma significantly elevate the risk of SSIs in LC. Prophylactic antibiotics serve as a protective factor. Prompt identification and proactive management of these risk factors are crucial in clinical practice to minimize the incidence of infections and improve patient outcomes.

ACKNOWLEDGEMENTS

We sincerely thank every patient who participated in this study.