MSS16: NEUTROPHIL-TO-LYMPHOCYTE RATIO IN ACUTE CHOLECYSTITIS
Hillary Danis; Kelly Tang; Navtej Grewal; Samuel Grasso; William Beaumont Army Medical Center
Objectives: Laparoscopic cholecystectomy is one of the most common procedures performed, estimated 300,000 performed annually in the United States, including among the military population. Approximately 20 million people in the United States have gallstones, 20% are symptomatic, and 1-4% develop complications.
Acute cholecystitis is defined as inflammation secondary to impaired gallbladder emptying. Diagnosis is made by physical exam, laboratory, and imaging findings, best described in the 2018 Tokyo Guidelines. Acute cholecystitis can progress to advanced or complicated disease, encompassing necrotizing, gangrenous, hemorrhagic, suppurative, emphysematous, or perforated cholecystitis, with mortality rates approaching 50%. This emphasizes the need for rapid identification and treatment.
The neutrophil-to-lymphocyte ratio (NLR) is a novel metric for predicting acute inflammatory processes. We hypothesize that elevated preoperative NLR scores correlate with the presence of acute and complicated cholecystitis.
Methods: This study is a retrospective investigation of NLR as a predictor of the presence and severity of acute cholecystitis as determined via intraoperative and pathologic findings in patients who underwent cholecystectomy at a single military academic hospital between January 2015 and August 2021.
Data is sourced from the electronic medical record (EMR) to determine preoperative NLR score, intraoperative findings, and postoperative histopathologic final diagnosis. The independent variables are NLR. The dependent variables are intraoperative and pathologic findings. Statistical analysis was used to exclude outlier values that likely represented laboratory errors. Correlation was assessed with t-test, Point-Biserial, and Shapiro-Wilk testing.
Results: The study initially encompassed a total of 1,198 patients who underwent surgery between 2015 and 2021. Statistical analysis refinement resulted in 516 patients after removing likely erroneous outliers. Of these, 377 patients were diagnosed with acute cholecystitis on histopathology.
The statistical assumptions for conducting a t-test and Point-Biserial correlation were validated using the Shapiro-Wilk test for normality. The Point-Biserial Correlation Coefficient was 0.18, demonstrating statistically significant, though relatively weak, correlation. The t-test analysis yielded a t-statistic of 5.42 with a p-value less than 0.01.
Conclusion: Preliminary data from international centers have shown an elevated NLR in patients with acute cholecystitis. However, this has not been widely investigated in the United States. To our knowledge, this is the first retrospective investigation of data spanning six years at a single military academic hospital.
The statistical analyses demonstrated p-values <0.01, highlighting a significant correlation between presence of acute cholecystitis and elevated preoperative NLR. These findings may expedite patient triage and reduce time to definitive surgical therapy.