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Role of prophylactic antibiotics in elective laparoscopic cholecystectomy: A systematic review and meta-analysis

Backgrounds/Aims The role of prophylactic antibiotics for laparoscopic cholecystectomy in low-risk patients is still unclear. This study aimed to verify the conclusion of previous meta-analyses concerning the effectiveness of antibiotic prophylaxis for elective laparoscopic cholecystectomy in low-risk patients. Methods Comprehensive literature searches were performed on electric databases and manual searches. Randomized controlled trials (RCTs), prospective studies, and retrospective studies comparing antibiotic prophylaxis to placebo or no antibiotics in low-risk elective laparoscopic cholecystectomy were included. Results This study included 28 RCTs, three prospective studies, and three retrospective studies. In RCTs, prophylactic antibiotics did not prevent deep surgical site infections (SSI) (RR 1.10, 95% confidence interval [CI] [0.45–2.69], p=0.84) but reduced SSI (RR 0.70, 95% CI [0.53–0.94], p=0.02), and superficial SSI (RR 0.58, 95% CI [0.42–0.82], p=0.01). Prospective studies showed prophylactic antibiotics did not reduce superficial SSI (RR 0.35, 95% CI [0.01–8.40], p=0.52) but reduced SSI (RR 0.12, 95% CI [0.04–0.35], p=0.0001). In retrospective studies, antibiotic prophylaxis did not reduce SSI (RR 1.59, 95% CI [0.30–8.32], p=0.58). The pooled data (12121 patients) including RCTs and prospective and retrospective studies showed that prophylactic antibiotics were not effective in preventing deep SSI (RR 1.01 95% CI [0.46–2.21], p=0.98) but effective in reducing SSI (RR 0.67, 95% CI [0.51–0.88], p=0.003) and superficial SSI (RR 0.61, 95% CI [0.45–0.83], p=0.002). Conclusions The use of prophylactic antibiotics is effective for reducing the incidence of SSI and superficial SSI but is not effective for preventing deep SSI in low-risk patients who underwent elective laparoscopic cholecystectomy.

and prospective and retrospective studies on this topic.
This study aimed to verify the conclusion of previous meta-analyses.

MATERIALS AND METHODS
The study protocol for this systemic review and meta-analysis followed the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guidelines. 14 Searching and other resources MEDLINE, Embase, the Cochrane Central Register of Controlled Trials, PubMed, and KMbase were searched using medical subject heading terms and following keyword combinations: "laparoscopic," "cholecystectomy," "antibiotic," "prophylac," and "meta-analysis." Table 1 shows was ＞50% or p-value of Cochrane Q test was ＜0.1. The publication bias was evaluated to detect "small-study effects" by funnel plot. 54 RCTs and prospective and retrospective studies were pooled separately to minimize the bias. Sensitivity analysis was performed to assess whether including non-randomized studies or low-quality studies is appropriate in this meta-analysis. 17

Study selection
A total of 1472 studies were screened through electronic database using our search strategies in July 2018.
And 1096 articles were found by hand search. After investigation of title and abstract, 239 articles were screened.

Publication bias
Third, few RCTs provide the data regarding high-risk patients associated with diabetes mellitus, steroid or immunosuppressive therapy, biliary obstruction, jaundice, antibiotic intake 7 days prior to surgery, emergency cholecystectomy, acute or chronic cholecystitis 6 weeks before surgery, and open conversion surgery. Therefore, whether prophylactic antibiotics play a role in high-risk laparoscopic cholecystectomy still remains unclear. Fourth, the number of patients in the included studies is insufficient to avoid type II error because most of the trials, including RCTs and non-RCTs, in this meta-analysis showed a relatively low incidence rate of SSI and very low difference in incidence rate between the prophylactic antibiotic group and control group. Fifth, there was publication bias evaluated by funnel plot that showed asymmetry, which sug- also include diabetes, emergency surgery, long duration of procedures, ASA score of 3 or higher, recent episode of colic within 30 days before surgery and age ＞70 years as high-risk group for SSI. However, several studies 23,[25][26][27][28]46 included patients with an ASA score of 3 or the ASA score was not applied to inclusion criteria in several RCTs. 22,32,38,40,43 Therefore, future studies need to provide a consistent set of inclusion criteria based on guidelines for defining low-risk or high-risk groups for SSI.
In conclusion, the overall pooled data of this meta-anal-