Serum lactate level and mortality in metformin-associated lactic acidosis requiring renal replacement therapy: a systematic review of case reports and case series

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.

Reversible acute blindness in suspected metformin-associated lactic acidosis: a case report

BACKGROUND

Metformin is commonly used for the treatment of type 2 diabetes mellitus. Its multiple advantages include low risk of hypoglycemia, weight neutrality, low cost, and cardioprotective and anti-inflammatory effects. Renal insufficiency is one of the contraindications for its use. Inadvertent prescription in patients with renal insufficiency may lead to metformin-associated lactic acidosis, which brings a high risk of mortality. The early recognition and management of metformin-associated lactic acidosis are essential.

CASE REPORT

We present the case of a 58-year-old Hui woman with a history of type 2 diabetes mellitus with nephropathy and heart disease for which she was treated with metformin, insulin, and heart medications. She developed nausea, vomiting, anion gap metabolic acidosis due to hyperlactatemia, and acute kidney injury. She was hospitalized to receive intravenous hydration and correction of metabolic acidosis after she suddenly developed blindness. The diagnostic workup ruled out central causes and her symptoms resolved briefly after continuous venovenous hemodialysis was initiated, confirming the diagnosis of metformin-associated lactic acidosis.

CONCLUSIONS

Metabolic disruption can cause acute blindness. Metabolic acidosis in a patient with a history of metformin intake should suggest the possibility of metformin-associated lactic acidosis, which must be treated immediately, without waiting for the results of other examinations, especially in patients with sudden blindness. Further study of reversible blindness-associated severe metabolic acidosis is needed.

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.

Quality and Characteristics of 4241 Case Reports of Lactic Acidosis in Metformin Users Reported to a Large Pharmacovigilance Database

Objective

Metformin-associated lactic acidosis (MaLA) occurs rarely and is thus difficult to study. We analysed 4241 individual case safety reports of lactic acidosis (LA) that implicated metformin as a suspected drug reported to the pharmacovigilance database of Merck KGaA, Darmstadt, Germany. The primary objective was to review reports for quality and completeness of data to support diagnoses of MaLA. We also explored the correlations between reported biomarkers, and associations between biomarkers and outcomes.

Research Design and Methods

Records were analysed for completeness in supporting diagnoses of LA or metformin-associated LA (MaLA), against commonly used diagnostic criteria. Correlations between indices of exposure to metformin and biomarkers of LA and mortality were investigated.

Results

Missing data was common, especially for plasma metformin. Clinical/biomarker evidence supported a diagnosis of LA in only 33% of cases (LA subpopulation) and of MaLA in only 9% (MaLA subpopulation). The metformin plasma level correlated weakly with plasma lactate (positive) and pH (negative). About one-fifth (21.9%) of cases reported a fatal outcome. Metformin exposure (plasma level or dose) was not associated with increased mortality risk (there was a suggestion of decreased risk at higher levels of exposure to metformin). Plasma lactate was the only variable associated with increased risk of mortality. Examination of concomitant risk factors for MaLA identified renal dysfunction (including of iatrogenic origin) as a potential driver of mortality in this population.

Conclusion

Despite the high frequency of missing data, this is the largest analysis of cases of MaLA supported by measurements of circulating metformin, and lactate, and pH, to date. Plasma lactate, and not metformin dose or plasma level, appeared to be the main driver of mortality in the setting of LA or MaLA. Further research with more complete case reports is required.

Cardiac Dysfunction Due to Thiamine Deficiency after Hemodialysis for Biguanide-related Lactic Acidosis

Biguanide is an ideal drug for the treatment of type 2 diabetes mellitus. When used appropriately, the incidence of lactic acidosis is reported to be very low. Risk factors associated with biguanide-related lactic acidosis include chronic kidney disease, congestive heart failure, alcohol use, severe dehydration, shock, hypoxic states, sepsis, and advanced age. We herein report a case of cardiac dysfunction due to thiamine deficiency after hemodialysis in a patient with suspected biguanide-related lactic acidosis. Patients who develop severe lactic acidosis while taking biguanides should be given a large dose of thiamine without delay, given the possibility of thiamine deficiency as a complication.

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

Background

Metformin-associated lactic acidosis (MALA) is a rare event but underrecognition may lead to unfavorable outcomes in type 2 diabetes patients. While many risk factors of MALA have been identified, how to reduce mortality from MALA is a matter of debate. This study aimed to explore the factors associated with 30-day mortality amongst MALA patients.

Methods

An observational study enrolled patients diagnosed with MALA between January 2014 and December 2017. MALA was defined by a history of metformin administration, metabolic acidosis (arterial blood gas pH <7.35 or HCO₃ <15 mmol/L), and elevated plasma lactate level (>5 mmol/L). We examined risk factors including age, sex, underlying diseases, current medications, blood tests, disease severity, and dialysis data. Mortality status was identified from medical records or report on telephone.

Results

We included 105 MALA patients. Most patients (95.2%) were diagnosed acute kidney injury stage 3 according to KDIGO 2012 definition. The 30-day mortality rate was 36.2% and dialysis rate was 85.7%. The survivors had higher proportions of underlying chronic kidney disease, presence of metabolic acidosis, receiving renal replacement therapy within 6 hours, and haemodialysis, whereas the non-survivors had higher percentage of hypertension and disease severity. Lower APACHE II score (HR = 0.95; 95%CI, 0.91–0.99; p = 0.038), time to dialysis < 6 hours (0.31; 0.14–0.69; 0.004), and haemodialysis (0.20;0.06–0.67; 0.010) were associated with lower 30-day mortality, using multivariate Cox-regression analysis.

Conclusions

Mortality rate amongst patients with MALA was high. Early dialysis treatment within 6 hours after admission and haemodialysis were independently associated with lower 30-day mortality. The large scale, well-designed studies need to confirm these encouraging results.

Metformin toxicity: A meta-summary of case reports

BACKGROUND

Metformin is arguably the most commonly prescribed oral hypoglycemic agent for the management of diabetes. Due to the lack of randomized control trials, most of the data pertaining to the clinical course, therapeutic interventions and outcomes of patients with metformin induced toxicity has come from case reports or series.

AIM

To analyse the symptomology, clinical interventions and outcomes of patients presenting with severe metformin toxicity by reviewing the published case reports and series.

METHODS

We performed a systematic search from PubMed, Science Direct, Reference Citation Analysis (https://www.referencecitationanalysis.com/) and Google Scholar databases using the terms “metformin” AND “toxicity” OR “overdose” OR “lactic acidosis” OR “hyperlactatemia”. The inclusion criteria were: (1) Case reports or case series with individual patient details; and (2) Reported toxicity or overdose of metformin in adults, published in the English language. Data regarding baseline demographics, clinical presentation, therapeutic interventions, intensive care unit course and overall outcome were collected.

RESULTS

Two hundred forty-two individual cases were analysed, from 158 case reports and 26 case series, with a cumulative mortality of 19.8%. 214 (88.4%) patients were diabetics on metformin. 57 (23.6%) had acute ingestion, but a great majority (76.4%) were on metformin in therapeutic doses when they developed toxicity. Metformin associated lactic acidosis (MALA) was the most commonly reported adverse effect present in 224 (92.6%) patients. Most of the patients presented with gastrointestinal and neurological symptoms and a significant number of patients had severe metabolic acidosis and hyperlactatemia. The organ support used was renal replacement therapy (RRT) (68.6%), vaso-pressors (58.7%) and invasive mechanical ventilation (52.9%). A majority of patients (68.6%) received RRT for toxin removal, renal dysfunction and correction of MALA. Patients with lowest pH and highest serum lactate and metformin levels also had favourable outcomes with use of RRT.

CONCLUSION

Most of the reported cases were on therapeutic doses of metformin but developed toxicity after an acute deterioration in renal functions. These patients may develop severe lactic acidosis, leading to significant morbidity and need for organ support. Despite severe MALA and the need for multiple organ support, they may have good outcomes, especially when RRT is used. The dose of metformin, serum pH, lactate and metformin levels may indicate the severity of toxicity and the need for aggressive therapeutic measures but may not necessarily indicate poor outcomes.

Clinical presentations and prognosis of metformin-associated lactic acidosis patients in the intensive care unit: A 20-year survey

METHODS

We retrospectively analyzed 82 adult patients with MALA admitted to the ICU over 20 years. The association between the clinical parameters and mortality post-MALA was estimated using logistic regression analysis.

RESULTS

Patients with MALA admitted to the ICU presented with clinical symptoms mainly associated with the head (40.24%), chest (41.46%), and abdomen (35.37%). Additionally, the PLL distribution significantly varied with age, APACHE II = Acute Physiology and Chronic Health Evaluation II (APACHE II) score, various laboratory parameters like nadir arterial bicarbonate level, multiple treatment modalities such as renal replacement therapy, and mortality. The overall mortality rate was 17.07%. After adjustment of age and gender, the significant predictors of mortality were APACHE II score, PLL, vasoactive support, ventilator support, and cardiopulmonary resuscitation.

CONCLUSIONS

Despite MALA being a rare event, it is necessary to evaluate its clinical characteristics, especially the associated PLL and mortality. In the current study, higher levels of APACHE II score and PLL show a greater likelihood of mortality in MALA patients.

Achieving High Dialysis Dose via Continuous Renal Replacement Therapy in the Setting of Metformin Associated Lactic Acidosis. A Case Series

Severe and life-threatening cases of metformin-associated lactic acidosis (MALA) are treated with renal replacement therapy. Intermittent hemodialysis is recommended, as it achieves rapid more elimination of metformin compared to continuous renal replacement therapy (CRRT). This case series describes 4 patients, 2 with acute metformin intoxications and 2 with insidious metformin toxicity. All were treated using a novel approach with dual CRRT to achieve rapid elimination of metformin. Three of the 4 patients survived to hospital discharge. Dual CRRT may be an effective alternative when dialysis is not readily available.

Metformin-associated lactic acidosis exacerbated by acute kidney injury in an overseas traveler

We report the case of metformin-associated lactic acidosis (MALA) exacerbated by acute kidney injury (AKI) in a 65-year-old Asian American woman who was an overseas traveler. She had vomiting and diarrhea before arriving in Osaka, Japan, from the Philippines. She suffered from worsening respiratory distress, consciousness loss and anuria the day after coming to Japan. When she arrived at our emergency room via ambulance, she appeared to be in a state shock. Arterial blood gas analysis revealed severe lactic acidosis (pH 6.681, PO₂ 302 Torr under O₂ supplementation, PCO₂ 15 Torr, HCO₃⁻1.7 mmol/L, and lactate 17.00 mmol/L). She also had renal failure (BUN 108 mg/dL and serum creatinine 8.68 mg/dL) with hyperkalemia (6.1 mEq/L). We collected medical information from family members, and found her prescription medicines including metformin, diuretics and angiotensin-converting enzyme inhibitor (ACEI). We diagnosed her with MALA due to an unintended overdose of metformin resulting from acute kidney injury that can be induced by ACEI and diuretics in the volume-depleted condition. We immediately started hemodialysis therapy. Although she had a temporary cardiopulmonary arrest at the beginning of the treatment, her physical status was gradually improved and the severe acidemia resolved. On hospital day 4, she had urine and no longer needed hemodialysis therapy. On day 14, she was discharged and returned to the United States without noticeable sequelae. This is a case report of an overseas traveler who was successfully rescued through the collection of accurate medical information and understanding of the pathological condition.

Reversible Total Vision Loss Caused by Severe Metformin-associated Lactic Acidosis: A Case Report

Introduction

Metformin is a biguanide used to treat diabetes mellitus (DM). Metformin-associated lactic acidosis (MALA) carries a high mortality and can occur in patients with renal failure from drug bioaccumulation. Reversible vision loss is a highly unusual, rarely reported complication of MALA. We present a case of a patient whose serum metformin concentration was unusually high and associated with vision loss.

Case Report

A 60-year-old woman presented to an outside hospital emergency department with acute vision loss after being found at home confused, somnolent, and hypoglycemic, having last being seen normal two days prior. She reported vomiting and diarrhea during that time and a recently treated urinary tract infection. The visual loss resolved with continuous renal replacement therapy.

Conclusion

This novel case of a patient with Type II DM prescribed metformin and insulin who developed reversible vision loss while suffering from MALA highlights the potential for vision loss in association with MALA.

Profound Metabolic Acidosis due to Metformin Intoxication Requiring Dialysis

Metformin-associated lactic acidosis (MALA) is a rare but life-threatening condition with often high mortality rates. Despite this, metformin continues to be one of the most commonly prescribed antihyperglycemic agents in the market. We present a unique case of a 61-year-old female with severe acidosis of pH = 6.72 and lactic acid of 26 mmol/L who presented obtunded after ingestion of an unknown amount of metformin. She was subsequently intubated, became hypotensive, and was initiated on vasopressors. She was swiftly started on a combination of intermittent hemodialysis (IHD) and bicarbonate therapy 7 hours after admission followed by continuous renal replacement therapy (CRRT) as she became more hemodynamically unstable. The patient's renal function improved, and she was discharged 7 days after admission with favorable sequelae. Dialysis is often reported in cases of severe MALA; however, it remains unclear how quickly dialysis should be initiated. This case aims to explore the benefits of quick initiation of extracorporeal measures in the forms of IHD and CRRT with concurrent bicarbonate supplementation. Furthermore, this case demonstrates the importance of clinical suspicion in metabolic acidosis in a patient on metformin therapy.

Mortality and renal prognosis in isolated metformin-associated lactic acidosis treated with continuous renal replacement therapy and citrate-calcium-anticoagulation

INTRODUCTION

Use of metformin increases plasma lactate concentration and may lead to metformin-associated lactic acidosis (MALA). Previous studies have suggested severe MALA to have a mortality of 17%-21%, but have included patients with other coincident conditions such as sepsis. The treatment of choice is continuous renal replacement therapy (CRRT), which has been performed using heparin analogues or no anticoagulation in former studies.

MATERIALS AND METHODS

Patients admitted to the Intensive Care Unit of Turku University Hospital Finland with lactic acidosis without any other recognizable etiology than concomitant metformin treatment who required CRRT between years 2010 and 2019 were included. CRRT was performed using regional citrate-calcium-anticoagulation. Data extracted included patient demographics, comorbidities, and clinical parameters at 6-hour intervals about 72 hours from admission. Creatinine and estimated glomerular filtration rate (eGFR) were measured at 1 year after MALA.

RESULTS

A total of 23 patients with isolated MALA were included in the study. Median (IQR) pH was 6.88 (6.81-7.07) and lactate 16.1 (11.9-23.0) mmol/L on admission. Median (IQR) duration of CRRT was 62 (41-70) hours. Seven patients (30%) required mechanical ventilation with a mean duration of 6.0 ± 3.0 days. 90-day mortality was 4.3% and 1-year mortality 13.0%. Creatinine (P = .02) and eGFR (P = .03) remained significantly altered at 1 year of follow-up compared to baseline.

CONCLUSIONS

MALA can be treated effectively and safely with CRRT and citrate-calcium-anticoagulation, usually required for 2-3 days. Mortality of patients with MALA treated with CRRT is low when other conditions inducing lactic acidosis are excluded. MALA episode may be associated with long-lasting kidney injury.

A Case Report on Metformin-Associated Lactic Acidosis and Transient Blindness

Metformin is the first-line treatment for any patient with type 2 diabetes. Metformin-associated lactic acidosis and transient blindness have only been reported in some case series and case reports. It is rare and presents especially in patients with underlying chronic kidney disease (CKD) Stage III and above and on high doses of metformin or with a normal dose of metformin and an associated renal injury. We present here a rare and interesting case of something similar. A 77-year-old woman with a past medical history of type 2 diabetes on metformin, obesity status post gastric bypass, CKD Stage III, presented with complaints of nausea, vomiting, confusion, abdominal pain, diarrhea, decreased urine output, sudden visual loss, and a hypoglycemic episode at home. She was hemodynamically stable. Lab work was suggestive of leukocytosis, hyperkalemia, severe high anion gap metabolic and lactic acidosis, acute-on-chronic kidney injury. Findings on the computed tomography (CT) brain, chest radiograph, and CT abdomen and pelvis could not explain the current scenario. She received Ringer’s lactate, a bicarbonate push, and an infusion. Acidosis continued to worsen, she became hypotensive requiring pressor support, and she was immediately taken for hemodialysis. All her symptoms, including vision loss, had improved with a single session of hemodialysis, even before the acidosis had corrected. Work-up for other causes of renal dysfunction came back negative. Metformin was discontinued. She was placed on insulin for her diabetes control.

Extracorporeal treatment of metforminassociated lactic acidosis in clinical practice: a retrospective cohort study

Purpose

To assess whether extracorporeal treatment (ECTR) improves outcome of patients with metformin-associated lactic acidosis (MALA) and to evaluate the clinical applicability of the Extracorporeal Treatments in Poisoning Workgroup (EXTRIP) criteria for starting ECTR in metformin poisoning.

Methods

Patients with metformin serum concentrations above 2 mg/l who were admitted in the Deventer Teaching Hospital between January 2000 and July 2019 and complied with the definition of MALA (pH < 7.35 and lactate concentration > 5 mmol/l) were included. Mortality and clinical parameters of patients treated with ECTR or not were compared. In addition, treatment of MALA in clinical practice was verified against the criteria of EXTRIP.

Results

Forty-two patients were included. Lactate (13.8 versus 10.5 mmol/l, p = 0.01), creatinine (575 versus 254 umol/l, p < 0.01)), metformin (29.4 versus 8.6 mg/l, p < 0.01) concentrations, and vasopressor requirement (72% versus 23%, p < 0.01) were significantly higher in the ECTR-group. Blood pH (7.05 versus 7.19, p = 0.03) and bicarbonate (6 versus 11 mmol/l, p < 0.01) were significantly lower. Mortality, length of hospital stay, and mechanical ventilation requirement were not statistically different. In 83% of patients, treatment of MALA was in accordance with the EXTRIP criteria.

Conclusions

Although there was no statistical benefit in mortality shown from ECTR, ECTR might be lifesaving in MALA, considering the ECTR-group was significantly sicker than the non-ECTR-group.

The majority of patients were treated in line with the EXTRIP criteria. Severity of lactic acidosis and renal impairment were the main indications for initiating ECTR.

Electronic supplementary material

The online version of this article (10.1007/s00228-020-02857-5) contains supplementary material, which is available to authorized users.

Diagnostic et Prise en Charge de l’Acidose Métabolique Recommandations formalisées d’experts communes Société de réanimation de langue française (SRLF) – Société française de médecine d’urgence (SFMU)

L’acidose métabolique est un trouble fréquemment rencontré en médecine d’urgence et en médecine intensive réanimation. La littérature s’étant enrichie de nouvelles données concernant la prise en charge de l’acidose métabolique, la Société de Réanimation de Langue Française (SRLF) et la Société Française de Médecine d’Urgence (SFMU) ont élaboré des recommandations formalisées d’experts selon la méthodologie GRADE. Les champs de la stratégie diagnostique, de l’orientation et de la prise en charge thérapeutique ont été traités et vingt-neuf recommandations ont été formulées : quatre recommandations fortes (Grade 1), dix recommandations faibles (Grade 2) et quinze avis d’experts. Toutes ont obtenu un accord fort. L’application des méthodes d’Henderson-Hasselbalch et de Stewart pour le diagnostic du mécanisme de l’acidose métabolique est discutée et un algorithme diagnostique est proposé. L’utilisation de la cétonémie et des lactatémies veineuse et capillaire est également traitée. L’intérêt du pH, de la lactatémie et de sa cinétique pour l’orientation des patients en pré-hospitalier et aux urgences est envisagé. Enfin, les modalités de l’insulinothérapie au cours de l’acidocétose diabétique, les indications de la perfusion de bicarbonate de sodium et de l’épuration extra-rénale ainsi que les modalités de la ventilation mécanique au cours des acidoses métaboliques sévères sont traitées dans la prise en charge thérapeutique.

Metformin-associated lactic acidosis: A case reporting a serious complication in the perioperative period

The worldwide prevalence of diabetes mellitus (DM) has risen dramatically over the past two decades and this affects 10-15% of the surgical population¹. Metformin represents the mainstay of anti-hyperglycaemic therapy for type 2 DM, providing numerous beneficial effects. However, a rare but severe adverse effect is the development of metformin-associated lactic acidosis (MALA) with high mortality rate. We describe a severe case of MALA in the postoperative period that culminated in cardiac arrest. Whereby anaesthetists should be knowledgeable and skilled in the care of patients with diabetes being imperative to focus on preoperative assessment, optimisation, management of pre-existing treatment during the starvation period and identification of patients medicated with metformin at risk of developing MALA.

Intoxication à la metformine

La metformine, seul représentant disponible en France de la classe des biguanides, est un médicament antidiabétique largement prescrit. L’effet thérapeutique bénéfique du contrôle glycémique obtenu par inhibition de la néoglucogenèse est objectivé par une réduction de la morbimortalité chez les patients diabétiques de type 2. Néanmoins, la metformine affecte aussi le métabolisme du lactate en augmentant sa production par la cellule. Ainsi, l’effet secondaire le plus redouté est l’acidose lactique associée à la metformine (metformin-associated lactic acidosis [MALA]). Celle-ci est liée à une augmentation brutale de la concentration en metformine dans le sang et dans les tissus, que ce soit après ingestion d’une grande quantité de médicament ou plus souvent dans les suites d’une insuffisance rénale aiguë chez un patient traité au long cours. Dans ce contexte d’acidose métabolique majeure avec hyperlactatémie, la sévérité des défaillances d’organes conditionne le pronostic. La prise en charge thérapeutique est symptomatique avec recours précoce à une épuration extrarénale dans les formes sévères ou ne répondant pas au traitement initial. La prévention de la MALA repose avant tout sur le respect des contreindications de la metformine chez les patients diabétiques.

Diagnosis and management of metabolic acidosis: guidelines from a French expert panel

Metabolic acidosis is a disorder frequently encountered in emergency medicine and intensive care medicine. As literature has been enriched with new data concerning the management of metabolic acidosis, the French Intensive Care Society (Société de Réanimation de Langue Française [SRLF]) and the French Emergency Medicine Society (Société Française de Médecine d’Urgence [SFMU]) have developed formalized recommendations from experts using the GRADE methodology. The fields of diagnostic strategy, patient assessment, and referral and therapeutic management were addressed and 29 recommendations were made: 4 recommendations were strong (Grade 1), 10 were weak (Grade 2), and 15 were experts’ opinions. A strong agreement from voting participants was obtained for all recommendations. The application of Henderson–Hasselbalch and Stewart methods for the diagnosis of the metabolic acidosis mechanism is discussed and a diagnostic algorithm is proposed. The use of ketosis and venous and capillary lactatemia is also treated. The value of pH, lactatemia, and its kinetics for the referral of patients in pre-hospital and emergency departments is considered. Finally, the modalities of insulin therapy during diabetic ketoacidosis, the indications for sodium bicarbonate infusion and extra-renal purification as well as the modalities of mechanical ventilation during severe metabolic acidosis are addressed in therapeutic management.

Lactic acidosis due to metformin in type 2 diabetes mellitus and chronic kidney disease stage 3-5: is it significant?

PURPOSE

To study the incidence of lactic acidosis due to metformin in patients with type 2 diabetes mellitus (T2DM) and chronic kidney disease (CKD) stage 3-5.

METHODS

We estimated plasma lactate in patients of CKD stage 3 and worse who were continuing metformin on their own prior to stopping the drug.

RESULT

Of 40 patients included, median duration of T2DM was 60 months (interquartile range IQR 24-120). The mean serum creatinine was 309.4 ± 159.1 µmol/L and mean eGFR was 27.82 ± 12.93 mL/min/1.73 m² with 3 (7.5%), 16 (40%), 11 (27.5%) and 10 (25%) in CKD stages 3a, 3b, 4 and 5, respectively. They were receiving metformin for a median duration of 24 months (IQR 12.5-60), an average dose of 896 ± 350 mg per day. The median of plasma lactate was 1.36 mmol/L (IQR 1.11-1.75 mmol/L) with three (7.5%) having levels above normal, two (20%) in CKD stage 5 and one (9.1%) in stage 4.

CONCLUSION

Metformin can be safely used in CKD stage 3 and with regular measurement of plasma lactate in later stages.

Effect of metformin on exercise capacity: A meta-analysis

AIMS

To evaluate the effect of metformin on various parameters of exercise capacity [oxygen consumption (VO₂), peak oxygen consumption (VO_2peak), heart rate (HR), exercise test duration, respiratory exchange ratio (RER), rating of perceived exertion (RPE), lactate and ventilatory anaerobic threshold (VAT)].

METHODS

Studies reporting change in VO₂ or VO_2peak after metformin administration were included. Subgroup analyses were performed as applicable. Mean difference with 95% CIs were pooled using random-effects model [RevMan (v5.3)].

RESULTS

There were no changes in VO₂ and VO_2peak in the overall population [VO₂: n = 388, mean difference: -0.12 ml/kg/min, 95% CI: -0.74, 0.51, p = 0.71 (i² = 0%, p = 0.99); VO_2peak: n = 345, mean difference: 0.41 ml/kg/min, 95% CI: -0.51, 1.33, p = 0.38 (i² = 0%, p = 0.89)], healthy volunteers and patients (type 2 diabetes mellitus, insulin resistance, impaired glucose tolerance/impaired fasting glucose and metabolic syndrome). For patients with insulin resistance, there was a decrease in VO_2peak, but not VO₂. In the overall population, there was a significant decrease in HR and RER, a significant increase in RPE, and no changes in exercise test duration and VAT. In addition, there was an increased VAT in the healthy volunteers.

CONCLUSIONS

In the overall population, metformin did not affect VO₂, VO_2peak, exercise test duration and VAT, although it significantly decreased HR, RER and increased RPE.

The risk factors of linezolid-induced lactic acidosis: A case report and review

BACKGROUND

In recent years, linezolid is increasingly used in multidrug-resistant bacteria therapy. At the same time, linezolid-induced lactic acidosis has been continually reported as a serious side effect. Notably, to our knowledge, there are limited available literatures that evaluate risk factors for linezolid-induced lactic acidosis, and there is no highly reliable study on the relationship between linezolid-induced lactic acidosis and age or gender. However, clinicians need relevant information to advice on the use of linezolid. Therefore, we report on a case of life-threatening lactic acidosis after 3 doses of linezolid exposure and evaluate the risk factors of linezolid-induced lactic acidosis.

METHODS

Cases of linezolid-induced lactic acidosis reported in PubMed were searched. Several characteristics and data of case numbers and deaths were extracted for analysis.

RESULTS

A total of 35 articles including 47 cases were included in this study. Twelve patients (25.5%) died due to linezolid-induced lactic acidosis. At the cut-offs of 7, 14, and 28 days, the mortalities were 27.3%, 20%, and 27.3%. No statistically significant difference was observed according to age and gender. However, the proportion (27.7% and 29.8%) and mortality (30.8% and 35.7%) of male patients were much higher than females in both ≥65 and <65 years old groups (proportion: 15.2% and 23.9%; mortality: 14.3% and 18.2%).

CONCLUSION

The mortality of linezolid-induced lactic acidosis was relatively high. The duration of linezolid use and age might not be risk factors. Gender (specifically, male) might be related to the mortality of linezolid-induced lactic acidosis.

Association of Metformin Use With Risk of Lactic Acidosis Across the Range of Kidney Function: A Community-Based Cohort Study

Importance

Approximately 1 million patients in the United States with type 2 diabetes mellitus and mild-to-moderate kidney disease do not receive guideline-directed therapy with metformin. This may reflect uncertainty regarding the risk of acidosis in patients with chronic kidney disease.

Objective

To quantify the association between metformin use and hospitalization with acidosis across the range of estimated glomerular filtration rate (eGFR), accounting for change in eGFR stage over time.

Design, Setting, and Participants

Community-based cohort of 75 413 patients with diabetes in Geisinger Health System, with time-dependent assessment of eGFR stage from January 2004 until January 2017. Results were replicated in 67 578 new metformin users and 14 439 new sulfonylurea users from 2010 to 2015, sourced from 350 private US health systems.

Exposures

Metformin use.

Main Outcomes and Measures

Hospitalization with acidosis (International Classification of Diseases, Ninth Revision, Clinical Modification code of 276.2).

Results

In the primary cohort (n = 75 413), mean (SD) patient age was 60.4 (15.5) years, and 51% (n = 38 480) of the participants were female. There were 2335 hospitalizations with acidosis over a median follow-up of 5.7 years (interquartile range, 2.5-9.9 years). Compared with alternative diabetes management, time-dependent metformin use was not associated with incident acidosis overall (adjusted hazard ratio [HR], 0.98; 95% CI, 0.89-1.08) or in patients with eGFR 45 to 59 mL/min/1.73 m2 (adjusted HR, 1.16; 95% CI, 0.95-1.41) and eGFR 30 to 44 mL/min/1.73 m2 (adjusted HR, 1.09; 95% CI, 0.83-1.44). On the other hand, metformin use was associated with an increased risk of acidosis at eGFR less than 30 mL/min/1.73 m2 (adjusted HR, 2.07; 95% CI, 1.33-3.22). Results were consistent when new metformin users were compared with new sulfonylurea users (adjusted HR for eGFR 30-44 mL/min/1.73 m2, 0.77; 95% CI, 0.29-2.05), in a propensity-matched cohort (adjusted HR for eGFR 30-44 mL/min/1.73 m2, 0.71; 95% CI, 0.45-1.12), when baseline insulin users were excluded (adjusted HR for eGFR 30-44 mL/min/1.73 m2, 1.16; 95% CI, 0.87-1.57), and in the replication cohort (adjusted HR for eGFR 30-44 mL/min/1.73 m2, 0.86; 95% CI, 0.37-2.01).

Conclusions and Relevance

In 2 real-world clinical settings, metformin use was associated with acidosis only at eGFR less than 30 mL/min/1.73 m2. Our results support cautious use of metformin in patients with type 2 diabetes and eGFR of at least 30 mL/min/1.73 m2.

Hemodialysis in metformin-associated lactic acidosis due to acute overdose in a metformin-naïve patient

Metformin is a common and generally well-tolerated medication in the treatment of diabetes but rarely has been implicated as the cause for metformin-associated lactate acidosis. This is usually caused by decreased elimination from renal dysfunction but is rarely described after an acute ingestion. We present a case of an acute intentional overdose of metformin in a metformin-naïve patient without renal dysfunction. The patient gradually developed altered mental status, tachypnea, hypotension, hyperglycemia, hypoglycemia, hypothermia, and vasoplegic shock unresponsive to vasopressor support. Despite attempts at alkalinization, the patient developed a lactic acidosis with a pH of 6.9 and lactate of 33 mmol/L. Hemodialysis was performed with rapid improvement of clinical status. This case provides a clinical context in the acute setting and illustrates the rare need for extracorporeal support in this setting, which may be lifesaving.