Lactic Acid Is an Independent Predictor of Mortality and Improves the Predictive Value of Existing Risk Scores in Patients Presenting With Acute Gastrointestinal Bleeding

BACKGROUND: There are validated clinical risk scores for risk stratifying patients presenting with acute upper gastrointestinal bleed (GIB), including Glasgow-Blatchford score (GBS), Pre-endoscopic Rockall score (RS-PE) and post-endoscopic complete Rockall Score (RS-C), and AIMS65. Several studies have explored the predictive value of lactic acid (LA) in the context of GI bleeding, but the prognostic role of LA and its incremental value in combination with existing clinical risk scores is not well defined. METHODS: We conducted a retrospective analysis of consecutive patients presenting to the emergency department of a single large academic tertiary care center from January 2014 to December 2015 with a charted diagnosis of acute GIB, inclusive of both upper and lower sources. We evaluated the independent role of LA as well as three clinical risk scores for predicting in-hospital mortality in these patients. RESULTS: Out of 704 patients admitted with acute GI bleeding, 366 patients had LA measured on presentation to the emergency department. The mean LA level, GBS, RS-PE and RS-C were found to be significantly higher in non-survivors, while there was no difference in the mean AIMS65 score between survivors and non-survivors. A multivariate logistic regression analysis showed that LA level was an independent predictor of in-hospital mortality. The area under the curve (AUC) for the receiver operator characteristic for RS-C, RS-PE, and GBS were 0.742, 0.675, and 0.652, respectively. When integrating LA into the above risk scores, the AUC for RS-C, RS-PE, and GBS showed statistical significance improvements to 0.780 (P = 0.04), 0.774 (P = 0.012), and 0.706 (P = 003), respectively. CONCLUSIONS: In unselected patients with GIB who presented to the emergency department, LA is an independent predictor of in-hospital mortality. Integration of LA into RS-C, RS-PE, and GBS risk scores improved their ability to predict in-hospital mortality. The modified LA-based RS-PE (L-Rockall pre-endoscopic) score demonstrated predictive value comparable to the post-endoscopic RS-C.