A novel preoperative score to predict severe acute cholecystitis.

BACKGROUND: In a large multicenter trial, The Parkland Grading Scale(PGS) for acute cholecystitis outperformed other grading scales and has a positive correlation with complications but is limited in its inability to preoperatively predict high-grade cholecystitis. We sought to identify preoperative variables predictive of high-grade cholecystitis(PGS 4 or 5).

METHODS: In a six-month period, patients undergoing cholecystectomy at a single institution with prospectively graded PGS were analyzed. Stepwise logistic regression models were constructed to predict high-grade cholecystitis. The relative weight of the variables was used to derive a novel score, the Severe Acute Cholecystitis Score(SACS). This score was compared to the Emergency Surgery Acuity Score(ESS), American Association for the Surgery of Trauma(AAST) preoperative score and Tokyo Guidelines(TG) for their ability to predict high-grade cholecystitis. SACS was then validated using the database from the AAST multicenter validation of the grading scale for acute cholecystitis.

RESULTS: Of the 575 patients that underwent cholecystectomy, 172(29.9%) were classified as high-grade. The stepwise logistic regression modeling identified 7 independent predictors of high-grade cholecystitis. From these variable the SACS was derived. Scores ranged from 0 to 9 points with a C statistic of 0.76, outperforming the ESS(C statistic of 0.60), AAST(0.53), and TG(0.70)(p-value <0.001). Using a cutoff of 4 or more on the SACS correctly identifies 76.2% of cases with a specificity of 91.3% and a sensitivity of 40.7%.In the multicenter database, there were 464 patients with a prospectively collected PGS. The C statistic for SACS was 0.74. Using the same cutoff of 4, SACS correctly identifies 71.6% of cases with a specificity of 83.8% and a sensitivity of 52.2%.

CONCLUSIONS: The Severe Acute Cholecystitis Score can preoperatively predict high-grade cholecystitis and may be useful for counseling patients and assisting in surgical decision making.

LEVEL OF EVIDENCE: Prognostic Level III.