Retrospective Study
Copyright ©The Author(s) 2020. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastrointest Surg. Feb 27, 2020; 12(2): 45-54
Published online Feb 27, 2020. doi: 10.4240/wjgs.v12.i2.45
Hyponatremia is associated with more severe biliary disease
Michael John Zobel, Lygia Stewart
Michael John Zobel, Lygia Stewart, Department of Surgery, University of California San Francisco, San Francisco, CA 94143, United States
Lygia Stewart, Department of Surgery, San Francisco VA Medical Center, San Francisco, CA 94121, United States
Author contributions: Zobel MJ and Stewart L designed the research, performed the research, contributed analytic tools, analyzed the data, and wrote the paper.
Institutional review board statement: This study was exempt from IRB approval as patient data was anonymously collected and not associated with any identifying information.
Informed consent statement: No consent was needed for this study.
Conflict-of-interest statement: All the authors have no conflict of interest related to the manuscript.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Corresponding author: Lygia Stewart, MD, Professor, Surgeon, Chief Surgeon, Department of Surgery, University of California San Francisco, 4150 Clement Street, San Francisco, CA 94143, United States. lygia.stewart@va.gov
Received: September 5, 2019
Peer-review started: September 5, 2019
First decision: October 13, 2019
Revised: November 4, 2019
Accepted: December 14, 2019
Article in press: December 14, 2019
Published online: February 27, 2020
Processing time: 132 Days and 10.8 Hours
ARTICLE HIGHLIGHTS
Research background

While hyponatremia has been studied in the context of other infectious and inflammatory disease states, sodium level has not yet been studied in a large-scale clinical study of patients with severe biliary disease. Serum sodium a common initial laboratory test for patients presenting with biliary disease, may serve as an important diagnostic tool for assessing the underlying severity of illness.

Research motivation

Despite advances in both laboratory and radiographic technologies, identifying patients with severe biliary disease remains a challenge for health care providers in the acute setting. We felt that serum sodium could serve as a critical tool in identifying patients with severe illness, accelerating their care, and improving patient outcomes.

Research objectives

We sought to clarify the relationship between serum sodium and severe biliary disease. Specifically, our goals were to determine if a correlation existed between serum sodium and both illness severity and the presence/location of biliary bacteria. We also sought to determine if such a correlation existed with other clinical factors including the presence of gangrenous changes, Charlson comorbidity score, and glucose level.

Research methods

We utilized a prospectively collected, comprehensive quality outcomes database containing detailed patient demographics, clinical information, and outcomes spanning from March 1989 to October 2019 with 920 patients with gallstone disease. The lowest sodium level during the initial acute phase of illness, prior to therapeutic intervention was recorded. We determined illness severity based on pre-intervention findings and classified patients accordingly. The level of bacterial infection was determined using culture results from gallstones, bile, and blood; patients were stratified by the highest level of bacterial infection detected. Patients were also stratified by the Charlson Comorbidity Index.

Research results

We observed a progressive, statistically significant decrease in sodium level with worsening disease severity. We also observed an incremental decrease in serum sodium with ascending bacterial infection. Charlson Comorbidity Index and the presence of gangrenous changes were also independent predictors of decreased sodium on multivariate analysis.

Research conclusions

This study is the first to describe an inverse relationship between serum sodium and severity of biliary disease. Furthermore, it reveals that both underlying medical morbidity and acute illness severity contribute to decreased sodium levels, and that the effects are additive. This study justifies the use of serum sodium as a clinical predictor of the severity of biliary disease.

Research perspectives

The direction of future research regarding patients with low serum sodium and biliary disease should focus on the pathophysiologic cause of decreased serum sodium. The applications of this research have implications not only for patients with biliary disease, but with any inflammatory or infectious process.