Metformin-associated lactic acidosis and factors associated with 30-day mortality

Urgent-Start Peritoneal Dialysis in Metformin-Associated Lactic Acidosis: A Critical Alternative when Immediate Hemodialysis Is Unavailable

INTRODUCTION

Intermittent hemodialysis (IHD) is a preferable renal replacement therapy (RRT) option in metformin-associated lactic acidosis (MALA) due to rapid correct metabolic acidosis. However, IHD might not be started immediately. Immediate urgent-start peritoneal dialysis (iUSPD) is used as a life-saving dialysis option and then followed by IHD. The outcomes of iUSPD were compared with other extracorporeal dialysis in MALA.

METHODS

In two tertiary hospitals in Thailand, the outcomes of patients with MALA who had received three different RRT modalities (iUSPD followed by IHD, IHD, and continuous renal replacement therapy [CRRT]) from January 2015 to December 2019 were compared. The primary outcome was 30-day mortality. The secondary outcomes were door-to-dialysis time and 90-day RRT dependence.

RESULTS

A total of 180 MALA cases that required dialysis were included (20 iUSPD, 120 IHD, and 40 CRRT). Their mean age was 64 years. Most of the patients had severe metabolic acidosis (mean pH 6.91, HCO3 6 mmol/L, and anion gap 40 mmol/L) and were critically ill. The 30-day mortality was 30% in iUSPD, 9.2% in IHD, and 32.5% in CRRT (p = 0.001). The mortality risk in the iUSPD group was not significantly different from those of the IHD and CRRT groups (adjusted HR 2.5, 95% CI: 0.65-9.6, and adjusted HR 0.75, 95% CI: 0.2-2.78, respectively). All dialysis modalities had comparable 90-day dialysis dependence. iUSPD exhibited the shortest door-to-dialysis time.

CONCLUSION

In MALA, iUSPD followed by IHD might be a viable RRT option to save patient lives if no other dialysis options are available.

Trends in Antidiabetic Drug Use and Safety of Metformin in Diabetic Patients with Varying Degrees of Chronic Kidney Disease from 2010 to 2021 in Korea: Retrospective Cohort Study Using the Common Data Model

BACKGROUND/OBJECTIVES

This study aimed to investigate trends in antidiabetic drug use and assess the risk of metformin-associated lactic acidosis (MALA) in patients with chronic kidney disease (CKD).

METHODS

A retrospective observational analysis based on the common data model was conducted using electronic medical records from 2010 to 2021. The patients included were aged ≥18, diagnosed with CKD and type 2 diabetes, and had received antidiabetic medications for ≥30 days. MALA was defined as pH ≤ 7.35 and arterial lactate ≥4 mmol/L.

RESULTS

A total of 8318 patients were included, with 6185 in CKD stages 1-2 and 2133 in stages 3a-5. Metformin monotherapy was the most prescribed regimen, except in stage 5 CKD. As CKD progressed, metformin use significantly declined; insulin and meglitinides were most frequently prescribed in end-stage renal disease. Over the study period, the use of SGLT2 inhibitors (13.3%) and DPP-4 inhibitors (24.5%) increased significantly, while sulfonylurea use decreased (p < 0.05). Metformin use remained stable in earlier CKD stages but significantly decreased in stage 3b or worse. The incidence rate (IR) of MALA was 1.22 per 1000 patient-years, with a significantly increased IR in stage 4 or worse CKD (p < 0.001).

CONCLUSIONS

Metformin was the most prescribed antidiabetic drug in CKD patients in Korea with a low risk of MALA. Antidiabetic drug use patterns varied across CKD stages, with a notable decline in metformin use in advanced CKD and a rise in SGLT2 inhibitor prescriptions, underscoring the need for further optimized therapy.

Metformin-associated lactic acidosis: a serious complication of a common drug

Metformin-associated lactic acidosis (MALA) is a rare and potentially life-threatening complication of metformin use. It typically occurs in patients who are diabetic and also have other risk factors for lactic acidosis, including kidney and liver conditions, malignancy, or use of certain medications. We report a case of MALA in a man in his 70s with diabetes who presented with gradually worsening gastrointestinal symptoms, including severe abdominal pain and nausea. He reported these symptoms in the setting of metformin use with an acute kidney injury (AKI), likely brought on by poor oral intake and excessive antibiotic use for a urinary tract infection. He was promptly started on intravenous fluids with a bicarbonate drip to concurrently treat his prerenal AKI and lactic acidosis, which resulted in rapid resolution of his symptoms. Renal function normalised within 12 days of admission. Since diabetic patients commonly use metformin and are also at higher risk of renal dysfunction, this case highlights the vulnerability of this group of patients and the need for increased knowledge and awareness of MALA.

A case of metformin-associated lactic acidosis with cardiogenic and vasoplegic shock supported by ECPella

Metfomin-associated lactic acidosis (MALA) is a rare but life-threatening complication of metformin use. We present a case of MALA with concurrent cardiogenic and vasoplegic shock which was successfully supported by ECPella (concurrent use of VA-ECMO and Impella). Early recognition, aggressive hemodynamic support with ECPella and early hemodialysis can be life-saving. Monitoring of both lactate and SvO2 trends can help understand the response to treatment.

An Analysis of Clinical Outcomes of Exploratory Pediatric Metformin Ingestions Reported to the Texas Poison Center Network From 2011 to 2021

Background: Poison centers develop triage threshold guidelines for pediatric metformin ingestions. Our network uses 1700 mg, or 85 mg/kg. Objective: To describe the dose, clinical course, and outcomes for inadvertent metformin ingestions in children 5 years old and younger reported to our statewide poison center network. Methods: We searched the poison center database 2011 to 2021 for metformin ingestions in patients 5 years and younger. Variables included age, sex, weight, dose, symptoms, outcome, and more. We used descriptive statistics with medians and interquartile ranges (IQR) for continuous variables. Results: Of 669 cases, exposures by age were 208 (31.1%) 1 to 2 years, and 275 (41.1%) 2 years. Weight was recorded in 342 (51.1%) (median 13.5 kg; IQR: 3.7 kg), and dose in 149 (22.3%) (median 500 mg; IQR: 500 mg). Milligram/kilogram values were available for 103 (15.4%) with median 42.4 mg/kg, IQR: 39 mg/kg. Most (647, 98.5%) exposures were unintentional. Most (445/669, 66.5%) were managed at a non-healthcare facility, while 204 (30.7%) were already at or referred to a healthcare facility. Of these 204 patients, 169 (82.8%) were evaluated and treated at the emergency department and discharged. Four (2%) were admitted to critical care, and 7 (3.4%) to the ward. Medical outcomes by effect were 5 (0.7%) minor, 2 (0.3%) moderate, 253 (37.8%) none, 292 (43.6%) not followed (minimal effects possible), and no major effects or deaths. Of 20 clinical occurrences reported, vomiting was most common (8, 1.2%). Conclusion: Despite little recorded dosage information, pediatric metformin ingestions under 85 mg/kg had predominantly uneventful medical outcomes.

Metformin-associated lactic acidosis: A mini review of pathophysiology, diagnosis and management in critically ill patients

Metformin is a common diabetes drug that may reduce lactate clearance by inhibiting mitochondrial oxidative phosphorylation, leading to metformin-associated lactic acidosis (MALA). As diabetes mellitus is a common chronic metabolic condition found in critically ill patients, pre-existing metformin use can often be found in critically ill patients admitted to the intensive care unit or the high dependency unit. The aim of this narrative mini review is therefore to update clinicians about MALA, and to provide a practical approach to its diagnosis and treatment. MALA in critically ill patients may be suspected in a patient who has received metformin and who has a high anion gap metabolic acidosis, and confirmed when lactate exceeds 5 mmol/L. Risk factors include those that reduce renal elimination of metformin (renal impairment from any cause, histamine-2 receptor antagonists, ribociclib) and excessive alcohol consumption (as ethanol oxidation consumes nicotinamide adenine dinucleotides that are also required for lactate metabolism). Treatment of MALA involves immediate cessation of metformin, supportive management, treating other concurrent causes of lactic acidosis like sepsis, and treating any coexisting diabetic ketoacidosis. Severe MALA requires extracorporeal removal of metformin with either intermittent hemodialysis or continuous kidney replacement therapy. The optimal time to restart metformin has not been well-studied. It is nonetheless reasonable to first ensure that lactic acidosis has resolved, and then recheck the kidney function post-recovery from critical illness, ensuring that the estimated glomerular filtration rate is 30 mL/min/1.73 m2 or better before restarting metformin.

Expanding the evidence for managing metformin poisoning to support decision-making

INTRODUCTION

Metformin-associated lactic acidosis is a well-described and commonly encountered condition associated with significant morbidity and mortality. Patients with metformin-associated lactic acidosis are frequently managed in the intensive care unit with supportive care, including volume resuscitation and consideration of an extracorporeal treatment to correct metabolic acidemia and remove metformin and lactate.

EXTRACORPOREAL TREATMENTS IN POISONING WORKGROUP

The Extracorporeal Treatments in Poisoning Workgroup published evidence-based consensus recommendations in 2015 regarding the use of extracorporeal treatment in metformin toxicity. These recommendations list both clinical and biochemical indications, and they outline the rationale and evidence supporting each recommendation.

NEW RESEARCH SINCE RECOMMENDATIONS WERE PUBLISHED

Subsequent publications have provided new information regarding metformin-associated lactic acidosis and its treatment. A retrospective study showed that patients who did not meet the Extracorporeal Treatments in Poisoning Workgroup criteria for initiation of an extracorporeal treatment had a 100% survival. In patients who met the criteria, survival was approximately 75%; only 66% of these patients received an extracorporeal treatment, and this treatment did not appear to impact survival. Two other retrospective studies in patients diagnosed with metformin-associated lactic acidosis noted that extracorporeal treatments did not improve survival. However, those who received an extracorporeal treatment were more severely ill, potentially supporting a benefit from this intervention. A systematic review of patients receiving continuous kidney replacement therapy identified an overall survival that was higher than the overall survival in patients included in the Workgroup publication. This led the authors to suggest that intermittent hemodialysis may not be the preferred treatment for metformin toxicity. However, a closer look at the Workgroup data identified improved survival with each decade since the initial reports in the 1970s. Furthermore, there are multiple reports of persistent metformin-associated lactic acidosis that did not improve with standard continuous kidney replacement therapy, prompting an increase in the dosage of the extracorporeal treatment. The data supporting these observations are largely derived from retrospective studies, which have inherent biases, so prospective studies are required.

PRESCRIBING EXTRACORPOREAL TREATMENTS FOR PATIENTS WITH METFORMIN POISONING

Case-based decision-making is always necessary, but in general, we continue to follow the Extracorporeal Treatments in Poisoning Workgroup criteria because a convincing reason for changing these has not yet been presented. This includes the use of intermittent hemodialysis where possible, particularly in cases of severe poisoning. For patients with less severe poisoning or when intermittent hemodialysis is not readily available, it is reasonable to trial continuous modalities with careful observation for deterioration.