Risk Factors For Lactic Acidosis Research Articles

A Review of the Novel Antidiabetic Medications: Efficacy, Safety and Innovation

Introduction: Type 2 diabetes is a chronic health condition affecting hundreds of millions of people. Type 2 diabetes has traditionally been combated with a combination of lifestyle modification, insulin therapy and pharmacological agents, including sulfonylureas, biguanides, thiazolidinediones and alpha-glucosidase inhibitors. Type 2 diabetes is associated with an increased risk of cardiovascular disease and the development of diabetic kidney disease. Although sulfonylureas are low-cost drugs and widely prescribed, they have been shown in recent cardiovascular outcome trials to present a high risk of hypoglycemia, which in turn increases the risk of negative cardiovascular outcomes. Metformin, a biguanide that is the most commonly-prescribed antidiabetic agent worldwide, is contraindicated in patients with risk factors for lactic acidosis, including heart failure and chronic kidney disease. Objectives: The last decade has seen significant advances in the development of novel antidiabetic agents shown to possess both reno- and cardioprotective qualities. This article aims to review the available literature and recent studies demonstrating the efficacy and safety of these agents individually, as well as exploring areas of future development in the field. Methods: The reporting of this review is based on the 2020 PRISMA statement. A literature search for all papers related to antidiabetic medication was conducted using reliable sources such PubMed and Google Scholar Databases, including a recent meta-analysis of renal and cardiovascular outcome trials. Conclusion: A critical analysis of clinical trials on type 2 diabetes and the two most severe comorbidities in cardiovascular and chronic kidney diseases may help cardiologists, urologists and diabetes specialists to adapt their therapeutic approaches to individual patients. Data related to antidiabetic effects of agents of natural origin accompanied by their Cardioprotective and renoprotective capacity testify benefits of these compounds as novel therapeutic agents.

Sufentanil: a risk factor for lactic acidosis in patients after heart valve surgery

BackgroundsHyperlactatemia is a common metabolic disorder after cardiac surgery with cardiopulmonary bypass. Epinephrine use has been identified as a potential cause of increased lactate levels after cardiac surgery. Stress can lead to an increase in catecholamines, mainly epinephrine, in the body. Exogenous epinephrine causes hyperlactatemia, whereas endogenous epinephrine released by stress may have the same effect. Opioids are the most effective anesthetics to suppress the stress response in the body. The authors sought to provide evidence through a retrospective data analysis that helps investigate the relationship between intraoperative opioid dosage and postoperative lactic acidosis after cardiac surgery.MethodsThe clinical data of 215 patients who underwent valvular heart surgery with cardiopulmonary bypass from July 2016 to July 2019 were analyzed retrospectively. Blood lactate levels were measured at 0.1 h, 2 h, 4 h, and 8 h after surgery. Patients with continuous increases in lactate levels and lactate levels exceeding 5 mmol/L at two or more time points were included in the lactic acidosis group, whereas the other patients were included in the control group. First, univariate correlation analysis was used to identify parameters that were significantly different between the two groups, and then multivariate regression analysis was conducted to elucidate the independent risk factors for lactic acidosis. Fifty-one pairs of patients were screened by propensity score matching analysis (PSM). Then, lactic acid levels at four time points in both groups were analyzed by repeated measures ANOVA.Resultshe EF (heart ejection fraction) (OR = 0.94, P = 0.003), aortic occlusion time (OR = 10.17, P < 0.001) and relative infusion rate (OR = 2.23, P = 0.01) of sufentanil was an independent risk factor for lactic acidosis after valvular heart surgery. The patients were further divided into two groups with the mean sufentanil infusion rate as the reference point. The data were filtered with PSM (Propensity Score Matching). Lactic acid values in both groups peaked at 4 h after surgery and then declined. The rate of lactic acid decline was significantly faster in the group with a higher sufentanil dosage than in the lower group. The difference was statistically significant (P < 0.05). There was also a significant difference in lactic acid levels at the four time points (0.1 h, 2 h, 4 h and 8 h after surgery) in both groups (P < 0.001).ConclusionThe inadequate intraoperative infusion rate of sufentanil is an independent risk factor for lactic acidosis after heart valve surgery. The possibility of lactic acidosis caused by this factor after cardiac surgery should be considered, which is helpful for postoperative patient management.

Metformin and Lactic Acidosis in Diabetic Patients

Metformin is the basic drug in the clinical treatment of Diabetes, often used in the treatment of Type 2 Diabetes Mellitus (T2DM).Its effect has been fully verified in the clinical treatment of T2DM. However, in the treatment of T2DM with metformin, there is still a certain probability of related lactic acidosis, and the fatality rate is high. Therefore, is the use of metformin drug treatment a direct risk factor for lactic acidosis in diabetic patients? This paper will review the hypoglycemic mechanism of metformin and related studies on lactic acidosis, so as to further explore the relationship between metformin and lactic acidosis in diabetic patients, and provide help and reference for metformin drugs in the clinical treatment of T2DM.

Incidence and Associated Risk Factors for Lactic Acidosis Induced by Linezolid Therapy in a Case-Control Study in Patients Older Than 85 Years.

Background: Serum lactic acid is considered a prognostic indicator in critically ill patients. However, studies on linezolid-induced lactic acidosis (LILA) are still limited. Individuals older than 85 years old (very elderly) have limited capacity for organ compensation, and LILA data from these patients are lacking. In this study, we evaluated the risk factors for LILA in patients older than 85 years and established a risk prediction model for geriatric practice.Methods: In this retrospective cohort study, blood gas analysis data and arterial lactate levels were monitored in patients older than 85 years during the use of teicoplanin or linezolid. After propensity score matching analyses, we compared the incidence of lactic acidosis between the teicoplanin and linezolid therapy groups and identified the risk factors of LILA.Results: The incidence of lactic acidosis was found to be much lower in the group receiving teicoplanin than those receiving linezolid therapy (0 vs. 35.7%; p < 0.0001). A duration of linezolid therapy ≥ 9 days [odds ratio (OR), 3.541; 95% confidence interval (CI), 1.161–10.793; p = 0.026], an arterial blood glucose level ≥ 8 mmol/L (OR, 4.548; 95% CI, 1.507–13.725; p = 0.007), and a high sequential organ failure assessment score (OR, 1.429; 95% CI, 1.213–1.685; p < 0.0001) were risk factors for LILA. The constructed risk model could be used to predict LILA (area under the curve, 0.849; specificity, 65.1%; sensitivity, 91.4%, with a negative predictive value of 93.2% and a positive predictive value of 59.3%).Conclusions: LILA can occur in patients older than 85 years after a relatively shorter duration of linezolid therapy. Therefore, close monitoring of blood gas and arterial lactate levels during linezolid therapy in the very elderly population is necessary.

Prevalence and risk factors of lactic acidosis in children with acute moderate and severe asthma, a prospective observational study

Lactic acidosis is a common complication of status asthmaticus in adults. However, data is sparse in children. The aim of this study was to describe the prevalence and risk factors for lactic acidosis in children hospitalised for acute moderate or severe asthma. A total of 154 children 2–17 years of age were enrolled in a prospective observational study conducted in a tertiary hospital. All had capillary blood gas assessment 4 h after the first dose of salbutamol in hospital. The primary endpoint was the prevalence of lactic acidosis. Potential contributing factors such as age, sex, BMI, initial degree of asthma severity, type of salbutamol administration (nebuliser or inhaler), steroids, ipratropium bromide, and glucose-containing maintenance fluid represented secondary endpoints. All in all, 87% of patients had hyperlactatemia (lactate concentration > 2.2 mmol/l). Lactic acidosis (lactate concentration > 5 mmol/l and anion gap ≥ 16 mmol/l) was observed in 26%. In multivariate analysis, age more than 6 years (OR = 2.8, 95% CI 1.2–6.6), glycemia above 11 mmol/l (OR = 3.2 95% CI 1.4–7.4), and salbutamol administered by nebuliser (OR = 10, 95% CI 2.7–47) were identified as risk factors for lactic acidosis in children with moderate or severe asthma.Conclusion: Lactic acidosis is a frequent and early complication of acute moderate or severe asthma in children.What is Known:• Lactic acidosis during acute asthma is associated with b2-mimetics administration.• Salbutamol-related lactic acidosis is self-limited but important to recognise, as compensatory hyperventilation of lactic acidosis can be mistaken for respiratory worsening and lead to inappropriate supplemental bronchodilator administration.What is New:• Lactic acidosis is a frequent complication of acute asthma in the paediatric population.• Age older than 6 years, hyperglycaemia, and nebulised salbutamol are risk factors for lactic acidosis during asthma.

TheAssociation between Metformin Therapy and Lactic Acidosis.

There is increasing evidence to suggest that therapeutic doses of metformin are unlikely to cause lactic acidosis. The aims of this research were (1) to formally evaluate the association between metformin therapy and lactic acidosis in published case reports using two causality scoring systems, (2) to determine the frequency of pre-existing independent risk factors in published metformin-associated lactic acidosis cases, (3) to investigate the association between risk factors and mortality in metformin-associated lactic acidosis cases, and (4) to explore the relationship between prescribed metformin doses, elevated metformin plasma concentrations and the development of lactic acidosis in cases with chronic renal impairment. A systematic review was conducted to identify metformin-associated lactic acidosis cases. Causality was assessed using the World Health Organisation-Uppsala Monitoring Centre system and the Naranjo adverse drugreaction probability scale. Compliance to dosing guidelines was investigated for cases with chronic renal impairment as well as the association between steady-state plasma metformin concentrations prior to admission. We identified 559 metformin-associated lactic acidosis cases. Almost all cases reviewed (97%) presented with independent risk factors for lactic acidosis. The prescribed metformin dose exceeded published guidelines in 60% of cases in patients with impaired kidney function. Metformin steady-state plasma concentrations prior to admission were predicted to be below the proposed upper limit of the therapeutic range of 5mg/L. Almost all cases of metformin-associated lactic acidosis reviewed presented with independent risk factors for lactic acidosis, supporting the suggestion that metformin plays a contributory role. The prescribed metformin dose, on average, exceeded the dosing recommendations by 1000mg/day in patients with varying degrees of renal impairment but the predicted pre-admission plasma concentrations did not exceed the therapeutic range.

Assessing the incidence of acidosis in patients receiving metformin with and without risk factors for lactic acidosis.

Despite strong recommendations to use metformin as first-line therapy for type 2 diabetes (T2DM), its use has been suboptimal, likely due to concerns of lactic acidosis. This study compared the association of acidosis in patients with T2DM prescribed metformin with those prescribed other antihyperglycemic medications or no medications. This was a retrospective cohort study of patients with newly diagnosed T2DM utilizing an administrative database, which includes medical and prescription claims. Eligible patients had a diagnosis of T2DM, had continuous health plan enrollment 3 months prior to study enrollment and during the study period, and were at least 18 years of age. Mutually exclusive exposure groups were metformin only, other antihyperglycemic medications, and no medication. Acidosis cases were stratified by exposure group and risk factors for lactic acidosis (chronic obstructive pulmonary disease, hepatic dysfunction, alcohol abuse, heart failure, renal insufficiency, age of 80 years or older, and a history of acidosis). Degree of renal insufficiency was not available. Associations between exposure and acidosis were estimated, and risk factors evaluated. A total of 132,780 patients met inclusion criteria: 24,936 (20%) metformin only group, 15,059 (11%) other antihyperglycemic medication group, and 92,785 (70%) no medication group. Acidosis was observed in 1.45 per 10,000 patient months (0.78 metformin, 1.59 other antihyperglycemic medication, 1.51 no medication). The unadjusted relative risk of acidosis was 0.5 for patients prescribed metformin only compared with the other exposure groups (95% confidence interval = 0.2-1.2). There was no significant difference in risk of acidosis between exposure groups, irrespective of risk factors for lactic acidosis. Risk of acidosis was similar with metformin only compared with those prescribed other antihyperglycemic medications or no medication. These results support expanded use of metformin for T2DM. Additional studies are needed to understand the impact of risk factor severity on risk of lactic acidosis.

Association between Metformin Use and Risk of Lactic Acidosis or Elevated Lactate Concentration in Type 2 Diabetes.

PurposeMetformin can reduce diabetes-related complications and mortality. However, its use is limited because of potential lactic acidosis-associated adverse effects, particularly in renal impairment patients. We aimed to investigate the association of metformin use with lactic acidosis and hyperlactatemia in patients with type 2 diabetes.Materials and MethodsThis was a cross-sectional study from a tertiary university-affiliated medical center. A total of 1954 type 2 diabetes patients were recruited in 2007–2011, and stratified according to the estimated glomerular filtration rate of 60 mL/min/1.73 m2. Lactic acidosis was defined as plasma lactate levels >5 mmol/L and arterial pH <7.35.ResultsMetformin was used in 61.4% of the patients with type 2 diabetes mellitus. Plasma lactate levels were not different in the patients with and without metformin use. There was no difference in prevalence of hyperlactatemia and lactic acidosis between the patients with and without metformin use (18.9% vs. 18.7%, p=0.905 for hyperlactatemia and 2.8% vs. 3.3%, p=0.544 for lactic acidosis). Similar results were observed in the patients with estimated glomerular filtration rate <60 mL/min/1.73 m2. Most patients with lactic acidosis had at least one condition related to hypoxia or poor tissue perfusion. Multiple regression analysis indicated no association between metformin use and lactic acidosis, whereas tissue hypoxia was an independent risk factor for lactic acidosis [odds ratio 4.603 (95% confidence interval, 1.327–15.965)].ConclusionMetformin use was not associated with hyperlactatemia or lactic acidosis in patients with type 2 diabetes.

Metformin-associated lactic acidosis: predisposing factors and outcome.

BackgroundMetformin is considered the first choice oral treatment for type 2 diabetes patients in the absence of contraindications. Rarely, life-threatening complications associated with metformin treatment are seen in some patients with underlying diseases. The aim of this study was to further investigate the clinical profiles and risk factors for metformin-associated lactic acidosis (MALA) and the treatment modalities according to survival.MethodsTo identify MALA, we performed a retrospective study in seven diabetic patients who were taking metformin and had been diagnosed with lactic acidosis at Inha University Hospital between 1995 and 2012. For each patient, we recorded the age, sex, daily metformin dosage, laboratory test results, admission diagnosis, and risk factors. Also, concurrent conditions, treatment modalities, and outcomes were evaluated.ResultsSix patients had risk factors for lactic acidosis before admission. All patients had renal impairment on admission as a precipitating risk factor. Five patients survived and two patients died despite early renal replacement therapy. Older patients tended to have a poorer prognosis.ConclusionRenal function must be monitored in elderly type 2 diabetes mellitus patients with underlying diseases and conditions causing renal impairment who begin metformin treatment. Accurate recognition of MALA and initiation of renal replacement are essential for treatment.

Metformin in Peritoneal Dialysis: A Pilot Experience

In a number of patients, the antidiabetic drug metformin has been associated with lactic acidosis. Despite the fact that diabetes mellitus is the most common cause of end-stage renal disease (ESRD) and that peritoneal dialysis (PD) is an expanding modality of treatment, little is known about optimal treatment strategies in the large group of PD patients with diabetes. In patients with ESRD, the use of metformin has been limited because of the perceived risk of lactic acidosis or severe hypoglycemia. However, metformin use is likely to be beneficial, and PD might itself be a safeguard against the alleged complications. Our study involved 35 patients with insulin-dependent type 2 diabetes [median age: 54 years; interquartile range (IQR): 47-59 years] on automated PD (APD) therapy. Patients with additional risk factors for lactic acidosis were excluded. Metformin was introduced at a daily dose in the range 0.5 - 1.0 g. All patients were monitored for glycemic control by blood sugar levels and HbA1c. Plasma lactic acid levels were measured weekly for 4 weeks and then monthly to the end of the study. Plasma and effluent metformin and plasma lactate levels were measured simultaneously. In this cohort, the median duration of diabetes was 18 years (IQR: 14 - 21 years), median time on PD was 31 months (IQR: 27 - 36 months), and median HbA1c was 6.8% (IQR: 5.9% - 6.9%). At metformin introduction and at the end of the study, the median anion gap was 11 mmol/L (IQR: 9 - 16 mmol/L) and 12 mmol/L (IQR: 9 - 16 mmol/L; p > 0.05) respectively, median pH was 7.33 (IQR: 7.32 - 7.36) and 7.34 (IQR: 7.32 - 7.36, p > 0.05) respectively, and mean metformin concentration in plasma and peritoneal fluid was 2.57 ± 1.49 mg/L and 2.83 ± 1.7 mg/L respectively. In the group overall, mean lactate was 1.39 ± 0.61 mmol/L, and hyperlactemia (>2 mmol/L to 5 mmol/L) was found in 4 of 525 plasma samples (0.76%), but the patients presented no symptoms. None of the patients registered a plasma lactate level above 5 mmol/L. We observed no correlation between plasma metformin and plasma lactate (r = 0.27). Metformin may be used with caution in APD patients with insulin-dependent type 2 diabetes. Although our study demonstrated the feasibility of metformin use in APD, it was not large enough to demonstrate safety; a large-scale study is needed.

The Association Between Admission Magnesium Concentrations and Lactic Acidosis in Critical Illness.

Although magnesium plays an important role in aerobic metabolism and magnesium deficiency is a common phenomenon in critical illness, the association between magnesium deficiency and lactic acidosis in the intensive care unit (ICU) has not been defined. This was a retrospective, cross-sectional study conducted at a 77 ICU bed tertiary medical center. Data pertaining to the first unique admission of any ICU patient between 2001 and 2008 were extracted from the Multiparameter Intelligent Monitoring in Intensive Care database. Hypomagnesemia was defined as serum magnesium <1.6 mg/dL. Mild and severe lactic acidosis were defined as lactate concentrations of >2 and > 4 mmol/L, respectively. Multivariate modeling was used to explore the association between magnesium and lactate concentrations. Of 8922 critically ill patients, 22.6% were hypomagnesemic. Hypomagnesemia was associated with an increased adjusted risk of mild lactic acidosis (odds ratio [OR] 1.71, 95% confidence interval [95%CI] 1.51-1.94, P < .001) and severe lactic acidosis (OR 1.56, 95%CI 1.32-1.84, P < .001) than the reference quartile. The association between hypomagnesemia and mild lactic acidosis was stronger in those at risk of magnesium deficiency, including diabetics (OR 2.02, 95%CI 1.51-2.72, P < .001) and alcoholics (OR 1.92, 95%CI 1.16-3.19, P = .01). As an internal model control, hypokalemia was not associated with an increased risk of lactic acidosis. Magnesium deficiency is a common finding in patients admitted to the ICU and is associated with lactic acidosis. Our findings support the biologic role of magnesium in metabolism and raise the possibility that hypomagnesemia is a correctable risk factor for lactic acidosis in critical illness.

Randomized trial of metformin vs insulin in the management of gestational diabetes

To evaluate glycemic control in women receiving metformin or insulin for gestational diabetes, and to identify factors predicting the need for supplemental insulin in women initially treated with metformin. Women with gestational diabetes who failed to achieve glycemic control with diet and exercise were randomized to receive metformin (n= 47) or insulin (n= 47). Criteria for inclusion were singleton pregnancy, diet, and exercise for a minimum period of 1 week without satisfactory glycemic control, absence of risk factors for lactic acidosis, and absence of anatomic and/or chromosome anomalies of the conceptus. Patients who were lost to prenatal follow-up were excluded. Comparison of mean pretreatment glucose levels showed no significant difference between groups (P= .790). After introduction of the drug, lower mean glucose levels were observed in the metformin group (P= .020), mainly because of lower levels after dinner (P= .042). Women using metformin presented less weight gain (P= .002) and a lower frequency of neonatal hypoglycemia (P= .032). Twelve women in the metformin group (26.08%) required supplemental insulin for glycemic control. Early gestational age at diagnosis (odds ratio, 0.71; 95% confidence interval, 0.52-0.97; P= .032) and mean pretreatment glucose level (odds ratio, 1.061; 95% confidence interval, 1.001-1.124; P= .046) were identified as predictors of the need for insulin. Metformin was found to provide adequate glycemic control with lower mean glucose levels throughout the day, less weight gain and a lower frequency of neonatal hypoglycemia. Logistic regression analysis showed that gestational age at diagnosis and mean pretreatment glucose level were predictors of the need for supplemental insulin therapy in women initially treated with metformin.

Incidence of lactic acidosis toxicity among patients on stavudine or zidovudine containing antiretroviral therapy at Lighthouse clinics

Although stavudine and zidovudine remain frequently used in low‐income countries in Africa, they are associated with long‐term toxicities. Lactic acidosis is one of the most serious toxicities in antiretroviral treatment (ART) and occurs predominantly in regimens containing stavudine (D4T) or zidovudine (AZT). We conducted this study to determine the incidence and risk factors for lactic acidosis among HIV‐positive patients that have been on ART for at least 6 months. This study will bridge the gap that exists due to scarcity of data on the extent of toxicities due to long‐term use of D4T and AZT. We conducted a retrospective cohort study using routine clinic data from the Lighthouse and Martin Preuss Centre electronic data systems. We used the clinic data collected between 1st January 2004 and 31st December 2011. We included into the analysis all patients that have been on D4T‐ or AZT‐containing ARV drugs for at least 6 months. We analysed the data using Poisson regression of the number of cases of lactic acidosis (LA) on gender, age at ART initiation, baseline BMI, and lipodystrophy in order to determine the incidence and risk factors for lactic acidosis. All statistical analyses were done at 5% significance level. We identified 14,854 patients that have ever been on D4T‐ or AZT‐containing ARV drugs for longer than 5 months. Of these, 43% were male and median age was 34 years. The total number of cases of confirmed LA was 342 with observed mortality rate 40% more than the patients without confirmed LA. There were 23.02 cases of LA for every 1000 patient‐years on D4T‐ or AZT‐containing ART regimens. The strongest risk factor identified for developing LA was having a baseline BMI &gt;25 with incidence rate ratio (IRR) 3.11 (95% CI: 2.49, 3.88). The IRR for patients with a diagnosis of lipodystrophy was 1.77 (95% CI: 1.35, 2.32). Patients aged &lt;30 years at ART initiation had 31% reduced risk of developing LA as compared to patients aged&gt;39 years at ART initiation. We were unable to detect any increased risk associated with gender. Clinicians should always have significantly higher index of suspicion of LA in patients with established lipodystrophy, aged more than 30 years at ART initiation and patients with higher baseline BMIs. The number of cases of fatal lactic acidosis that did not present to the clinic is unknown but is likely to be significant.

A Risk-Factor Guided Approach to Reducing Lactic Acidosis and Hyperlactatemia in Patients on Antiretroviral Therapy

BackgroundStavudine continues to be used in antiretroviral treatment (ART) regimens in many resource-limited settings. The use of zidovudine instead of stavudine in higher-risk patients to reduce the likelihood of lactic acidosis and hyperlactatemia (LAHL) has not been examined.MethodsAntiretroviral-naïve, HIV-infected adults initiating ART between 2004 and 2007 were divided into cohorts of those initiated on stavudine- or zidovudine-containing therapy. We evaluated stavudine or zidovudine use, age, sex, body mass index (BMI), baseline CD4 cell count, creatinine, hemoglobin, alanine aminotransferase, and albumin as predictors of time to LAHL with Cox Proportional Hazards (PH) regression models.ResultsAmong 2062 patients contributing 2747 patient years (PY), the combined incidence of LAHL was 3.2/100 PY in those initiating stavudine- and 0.34/100 PY in those initiating zidovudine-containing ART (RR 9.26, 95% CI: 1.28–66.93). In multivariable Cox PH analysis, stavudine exposure (HR 14.31, 95% CI: 5.79–35.30), female sex (HR 3.41, 95% CI: 1.89–6.19), higher BMI (HR 3.21, 95% CI: 2.16–4.77), higher creatinine (1.63, 95% CI: 1.12–2.36), higher albumin (HR 1.04, 95% CI: 1.01–1.07), and lower CD4 cell count (HR 0.96, 95% CI: 0.92–1.0) at baseline were associated with higher LAHL rates. Among participants who started on stavudine, switching to zidovudine was associated with lower LAHL rates (HR 0.15, 95% CI: 0.06–0.35). Subgroup analysis limited to women with higher BMI≥25 kg/m2 initiated on stavudine also showed that switch to zidovudine was protective when controlling for other risk factors (HR 0.21, 95% CI .07–0.64).ConclusionsStavudine exposure, female sex, and higher BMI are strong, independent predictors for developing LAHL. Patients with risk factors for lactic acidosis have less LAHL while on zidovudine- rather than stavudine-containing ART. Switching patients from stavudine to zidovudine is protective. Countries continuing to use stavudine should avoid this drug in women and patients with higher BMI.

Metformin associated lactic acidosis: incidence and clinical correlation with metformin serum concentration measurements

The reported incidence of metformin associated lactic acidosis (MALA) in type 2 diabetes mellitus (DM) is 3-9 cases per 100,000 patient-years. In clinical practice, 22-94% of patients using metformin have contraindications to metformin, so the incidence of MALA may be higher than reported. To estimate the incidence of MALA in type 2 DM patients by means of metformin serum concentration measurements and investigate the correlation of metformin serum concentration with the clinical outcome of MALA. MALA cases were identified by reviewing the medical records of patients with metformin serum concentrations measured between January 2000 and October 2008. MALA was defined as arterial pH <7·35 and lactate concentration >5·0 mmol/L in patients using metformin. The incidence of MALA was calculated from the number of cases and the at risk population. The correlation coefficient between the metformin and lactate concentration was calculated by linear regression. The relationship between metformin serum concentration, lactate concentration and outcome was examined by calculating the mean metformin and lactate concentration in patients who survived and those who died. The Student's t-test was used to compare groups. In 29 patients metformin serum concentration was measured, 16 had MALA. Eleven of the 16 MALA cases (69%) had risk factors for lactic acidosis in their medical history, 13 cases (81%) had renal failure on admission. The incidence of MALA was estimated at 47 per 100,000 patient-years, this is 5-16 times higher than previously reported. This may be explained by the use of metformin in the presence of risk factors for lactic acidosis. Survivors had a higher metformin serum concentration (18·9 mg/L) than non-survivors (2·9 mg/L, P = 0·006) which can be explained by less severe underlying disease in patients who survived MALA, rather than an effect of metformin itself. The incidence of MALA estimated from metformin serum concentration measurements in type 2 DM patients is 5-16 times higher than reported in literature. MALA is probably caused by the frequent use of metformin in the presence of risk factors for lactic acidosis. Metformin serum concentration measurements may aid in the timely diagnosis and therapy of MALA. The outcome of MALA is determined by the severity of the underlying disease, rather than by metformin itself.

Three cases of severe metformin-related lactic acidosis

The American Diabetes Association and the European Association for the Study of Diabetes published a consensus statement on the approach to hyperglycaemia in individuals with type 2 diabetes.1 In accordance with this statement, metformin is widely prescribed, as it is the first-line drug for type 2 diabetes treatment. Lactic acidosis incidence during metformin therapy is estimated to be two to nine cases per 100 000 patients per year, an incidence not too different from that reported in patients with type 2 diabetes who do not take metformin.2 In fact, there is some controversy concerning the association between metformin and lactic acidosis. Metformin does not seem to be the initial cause of lactic acidosis but could, possibly, precipitate the acid–base imbalance and contribute to the severity of the acidosis.3 The risk factors for metformin-related lactic acidosis include decreased renal, cardiac and hepatic functions and/or suspected tissue hypoxia. On the contrary, in recent years, several cases of severe lactic acidosis have been reported in the literature, even in the absence of these risk factors. Medical therapy for metformin-associated lactic acidosis includes management of concurrent diseases; mechanical ventilation to prevent muscle fatigue, to help to maintain respiratory compensation for metabolic acidosis and to optimize oxygenation; bicarbonate haemodialysis or continuous veno-venous haemofiltration (CVVH) to decrease the metformin level and correct acidosis; and intensive vasoactive support with norepinephrine or epinephrine. The use of bicarbonate is known to worsen intracellular acidosis and hyperlactacidaemia and remains controversial. In the last 14 months, three patients undergoing chronic metformin therapy have been admitted to our critical care unit for severe lactic acidosis (Table 1).Table 1: Patient characteristicsAll patients we saw were hypothermic with a high Simplified Acute Physiology Score II (SAPS II) score at admission. Two patients required high doses of epinephrine due to hypotension refractory to norepinephrine–dobutamine association. Liver function was never affected. Patient 1 and patient 2 had risk factors for lactic acidosis, as they had mild and moderate previous elevation of creatinine level, respectively; in these cases, metformin should be withdrawn. Patient 3 had no contraindication to metformin use.4 Two out of three had a mild infection before admission (patients 1 and 3). Diabetic nephropathy often develops insidiously. Moreover, infection or dehydration can rapidly lead to renal function impairment. Cohen and Woods divided lactic acidosis into two categories. Type A is lactic acidosis occurring in association with clinical evidence of poor tissue perfusion or oxygenation, whereas type B occurs when no clinical evidence of poor tissue perfusion or oxygenation exists. All three patients had developed acute renal failure, a known cause of type B lactic acidosis. Two patients had infections, which may also have contributed to tissue hypoxia and type A lactic acidosis. Regardless of the type of lactic acidosis in our patients, the incidence of metformin toxicity can be reduced with close monitoring of renal function. Serum creatinine should be checked at least annually, and probably more often in patients with exposure to risk factors for renal impairment.5 These cases suggest a high index of suspicion for metformin-associated lactic acidosis in older patients, a prompt metformin withdrawal during periods of suspected tissue hypoxia or impaired renal function and the importance of giving patients full information about this side-effect. We have outlined the importance of taking into account risk factors for lactic acidosis and contraindications in prescribing metformin. We also would like to emphasize that, despite the severity of clinical presentation, two patients had an excellent recovery.

Obesity As Risk Factor for Lactic Acidosis During Nucleoside Analogue Treatment

Obesity As Risk Factor for Lactic Acidosis During Nucleoside Analogue Treatment

Current Therapeutic Drugs for Type 2 Diabetes, Still Useful After 50 Years?

Current Therapeutic Drugs for Type 2 Diabetes, Still Useful After 50 Years?

Metformin, Sulfonylureas, or Other Antidiabetes Drugs and the Risk of Lactic Acidosis or Hypoglycemia

OBJECTIVE—Lactic acidosis has been associated with use of metformin. Hypoglycemia is a major concern using sulfonylureas. The aim of this study was to compare the risk of lactic acidosis and hypoglycemia among patients with type 2 diabetes using oral antidiabetes drugs.RESEARCH DESIGN AND METHODS—This study is a nested case-control analysis using the U.K.-based General Practice Research Database to identify patients with type 2 diabetes who used oral antidiabetes drugs. Within the study population, all incident cases of lactic acidosis and hypoglycemia were identified, and hypoglycemia case subjects were matched to up to four control patients based on age, sex, practice, and calendar time.RESULTS—Among the study population of 50,048 type 2 diabetic subjects, six cases of lactic acidosis during current use of oral antidiabetes drugs were identified, yielding a crude incidence rate of 3.3 cases per 100,000 person-years among metformin users and 4.8 cases per 100,000 person-years among users of sulfonylureas. Relevant comorbidities known as risk factors for lactic acidosis could be identified in all case subjects. A total of 2,025 case subjects with hypoglycemia and 7,278 matched control subjects were identified. Use of sulfonylureas was associated with a materially elevated risk of hypoglycemia. The adjusted odds ratio for current use of sulfonylureas was 2.79 (95% CI 2.23–3.50) compared with current metformin use.CONCLUSIONS—Lactic acidosis during current use of oral antidiabetes drugs was very rare and was associated with concurrent comorbidity. Hypoglycemic episodes were substantially more common among sulfonylurea users than among users of metformin.

Risk factors for lactic acidosis and severe hyperlactataemia in HIV-1-infected adults exposed to antiretroviral therapy

Background: Severe hyperlactataemia and lactic acidosis are rare serious complications of antiretroviral therapy (ART). Methods: Lactic acidosis was defined as pH < 7.35, bicarbonate < 20 mmol/l and raised lactate; hyperlactataemia as two consecutive lactates > 5 mmol/l. The case–control study of 110 cases and 220 controls(two randomly selected from treated patients by centre and calendar year) from centres in 10 countries included 40 (36.4%) female cases and 40 female controls (18.2%) (P < 0.001). Median age was 42.4 years [interquartile range (IQR, 36.0–52.5] for cases and 40 (IQR, 35.0–47.1) for controls (P = 0.013). More cases were nonwhite (41.9%) than controls (31.2%) (P = 0.032). Cases had a shorter duration of exposure to dideoxynucleosides. Results: After adjusting for age, gender and current CD4 cell count, hyperlactataemia/lactic acidosis remained associated with exposure to didanosine in every category of exposure duration but was most strongly associated with exposure < 12 months. In a separate multivariable model, apart from exposure to stavudine, didanosine, or even more strongly both, age above 40 years [odds ratio (OR), 2.6; 95% confidence interval (CI), 1.08–6.29], female gender (OR, 5.97; 95% CI, 1.92–18.5) and advanced immunosuppression were independent associations (CD4 cell count 200–349, 100–199 and < 100 cells/μl: OR, 3.89, 7.58 and 8.11, respectively). Interpretation: Hyperlactataemia/lactic acidosis was associated with exposure to dideoxynucleosides, female gender, advanced immunosuppression and possibly ethnicity. This has important consequences for choice of ART in resource-limited settings. The association with shorter duration of exposure may support the hypothesis of susceptibility in a small proportion of patients.