Retrospective evaluation of management guidelines for extracorporeal treatment of metformin poisoning

Abstract

Introduction

The Extracorporeal Treatments in Poisoning (EXTRIP) Workgroup defined criteria for extracorporeal toxin removal in patients with metformin poisoning. The primary objective of this study was to determine the benefit of extracorporeal toxin removal in patients meeting EXTRIP criteria. The secondary objective was to determine the performance characteristics of the EXTRIP criteria.

Methods

This was a single-center retrospective analysis of metformin poisoned patients. Inclusion criteria were: suspicion of metformin poisoning with at least one of the following present: lactate concentration >5 mmol/L; pH < 7.35; or impaired kidney function. Patient data were extracted by reviewers who were unaware of the study hypothesis. Cases were analyzed based on EXTRIP criteria, whether extracorporeal toxin removal was performed, and survival. Sensitivity, specificity, negative predictive value and positive predictive value were calculated with respect to the EXTRIP criteria and survival.

Results

Of 201 patients studied, 145 patients met recommended EXTRIP criteria (EXTRIP positive) and 56 patients did not (EXTRIP negative). Among patients who met recommended EXTRIP criteria, 96 received extracorporeal toxin removal and 49 did not. There was no difference in survival between these groups: 75.0% versus 73.5%, respectively (P >0.05). All 56 patients who did not meet EXTRIP criteria, survived (negative predictive value = 100%).

Discussion

The study did not demonstrate a survival benefit for extracorporeal toxin removal in those meeting EXTRIP criteria.

Conclusion

In this retrospective analysis, the recommended EXTRIP criteria had a negative predictive value for death of 100%. Further study is needed to evaluate the benefit of extracorporeal toxin removal in patients meeting EXTRIP criteria for metformin poisoning.

Keywords:

• Metformin
• EXTRIP
• hemodialysis
• extracorporeal therapy

Disclosure statement

No potential conflict of interest was reported by the authors.

Correction Statement

This article has been corrected with minor changes. These changes do not impact the academic content of the article.

Additional information

Funding

This was a trainee research grant through the American Academy of Clinical Toxicology [https://www.clintox.org/grants/toxicology-trainee-research-grant].