Impact of Japanese regulatory action on metformin-associated lactic acidosis in type II diabetes patients

Clinical efficacy and cost-effectiveness of metformin in different patient populations: A narrative review of real-world evidence

Over the past two decades, diabetes pharmacopoeia has flourished, with new drugs that, on top of their glucose-lowering efficacy, have been shown to protect the heart and the kidney. Despite these new opportunities, metformin retains a pivotal role among glucose-lowering agents. As one of the few available insulin sensitizers, metformin is an effective, safe, and overall well-tolerated drug backed by over 60 years of clinical experience, including evidence for potential benefits beyond glucose reduction across different ages, sexes, genetic backgrounds, geographical areas, and stages of disease. Although there is some discussion of whether metformin offers the most effective front-line option in newly diagnosed type 2 diabetes (T2D), it remains a natural companion to all other glucose-lowering agents. Furthermore, metformin comes at a very low cost and, as such, it has extremely high cost-effectiveness, particularly given the serious economic burden associated with diabetes complications. This financial advantage is particularly relevant in resource-constrained healthcare systems, where the affordability of metformin may be instrumental in implementing an effective treatment in an evergrowing number of individuals. We present here compelling real-world evidence in support of the clinical efficacy and cost-effectiveness of metformin across different patient populations, highlighting areas where more population-based studies are needed to further incorporate and consolidate its use in the pharmacological management of T2D.

Metformin exposure and the incidence of lactic acidosis in critically ill patients with T2DM: A retrospective cohort study

OBJECTIVE

The objective of this study was to investigate the correlation between metformin exposure and the incidence of lactic acidosis in critically ill patients.

METHODS

The patients with type 2 diabetes mellitus (T2DM) were included from Medical Information Mart for Intensive Care IV database (MIMIC-IV). The primary outcome was the incidence of lactic acidosis. The secondary outcomes were lactate level and in-hospital mortality. Propensity score matching (PSM) method was adopted to reduce bias of the confounders. The multivariate logistic regression was used to explore the correlation between metformin exposure and the incidence of lactic acidosis. Subgroup analysis and sensitivity analysis were used to test the stability of the conclusion.

RESULTS

We included 4939 patients. There were 2070 patients in the metformin group, and 2869 patients in the nonmetformin group. The frequency of lactic acidosis was 5.7% (118/2070) in the metformin group and it was 4.3% (122/2869) in the nonmetformin group. There was a statistically significant difference between the two groups (P < 0.05). The lactate level in the metformin group was higher than in the nonmetformin group (2.78 ± 2.23 vs. 2.45 ± 2.24, P < 0.001). After PSM, the frequency of lactic acidosis (6.3% vs. 3.7%, P < 0.001) and lactate level (2.85 ± 2.38 vs. 2.40 ± 2.14, P < 0.001) were significantly higher in the metformin group compared with the nonmetformin group. In multivariate logistic models, the frequency of lactic acidosis was obviously increased in metformin group, and the adjusted odds ratio (OR) of metformin exposure was 1.852 (95% confidence interval (CI) = 1.298-2.643, P < 0.001). The results were consistent with subgroup analysis except for respiratory failure subgroup. Metformin exposure increased lactate level but did not affect the frequency of lactic acidosis in patients of respiratory failure with hypercapnia. However, the in-hospital mortality between metformin and nonmetformin group had no obvious difference (P = 0.215). In sensitivity analysis, metformin exposure showed similar effect as the original cohort.

CONCLUSIONS

In critically ill patients with T2DM, metformin exposure elevated the incidence of lactic acidosis except for patients of respiratory failure with hypercapnia, but did not affect the in-hospital mortality.

Treatment patterns and satisfaction in patients with type 2 diabetes newly initiating oral monotherapy with antidiabetic drugs in Japan: results from the prospective Real-world Observational Study on Patient Outcomes in Diabetes (RESPOND)

INTRODUCTION

To present longitudinal data from the Real-world Observational Study on Patient Outcomes in Diabetes (RESPOND) in Japan.

RESEARCH DESIGN AND METHODS

In this multicenter, prospective, observational cohort study, patients with type 2 diabetes mellitus (T2DM) newly initiated on monotherapy were followed up for 2 years. Primary outcomes included changes in treatment pattern over time, target hemoglobin A1c (HbA1c) attainment and treatment satisfaction per Oral Hypoglycaemic Agent Questionnaire (OHA-Q).

RESULTS

Among 1474 enrolled patients (male, 62.1%; mean age, 59.7 years; HbA1c, 8.08%), the oral antidiabetic drug (OAD) monotherapy prescription rate decreased to 47.2% and that of 2 and ≥3 OADs increased to 14.8% and 5.4% at 24 months, respectively. Switch/add-on OAD was associated with higher HbA1c and body mass index (BMI), baseline OAD being non-dipeptidyl peptidase-4 inhibitor (DPP-4i)/non-sodium glucose cotransporter-2 inhibitor (SGLT2i), diabetes complications, no comorbidities and consulting a diabetes specialist. The mean (SD) HbA1c (%) was 6.73 (0.85) at 24 months. Higher HbA1c, diabetes complications, cardiovascular disease, being employed, no hypertension and younger treating physician were associated with ≥2 OAD classes prescription or target HbA1c non-attainment at 24 months. OHA-Q subscale scores were significantly higher in patients achieving (vs not achieving) target HbA1c and in those continuing monotherapy (vs combination therapy). Baseline age (<65 years), sex (female), HbA1c, alcohol use, use of non-‍DPP-4i OADs or non-T2DM drugs, diabetes complications and cardiovascular disease had a significant negative impact, while EuroQol five-dimensional five-level and Summary of Diabetes Self-Care Activities-specific diet scores, BMI and unemployment had a significant positive impact on OHA-Q scores at 24 months.

CONCLUSIONS

Primary outcomes show real-world treatment patterns and glycemic control over 2 years in patients with T2DM newly initiated on OAD monotherapy in Japan. Key factors associated with durability of initial monotherapy, target achievement or treatment satisfaction included baseline HbA1c, comorbidity and initial OAD choice.

A survey on consciousness towards the proper use of metformin and medical cost in Japanese patients with type 2 diabetes

To investigate the patients' consciousness regarding the use of metformin and medical cost in Japanese patients with type 2 diabetes taking metformin. This cross-sectional study investigated patients' general characteristics and consciousness regarding medical cost, kidney function, liver function, and metformin usage, using a self-administered, internet-based questionnaire. Among 1,000 patients, 81.0% felt unsatisfied with treatment for type 2 diabetes, with the main reason for dissatisfaction being high medical cost, with 540 patients reporting this. In addition, 16.8% of patients experienced treatment disruption and among them, 48.2% (81/168) answered that the reason was high medical cost. Over half of the patients did not understand their kidney and liver functions, respectively. Only 8.9% and 7.1% of patients knew both the words and meanings behind sick days and lactic acidosis, respectively. In conclusion, many patients with type 2 diabetes taking metformin were not satisfied with their treatments, with the main reason being high medical cost. Moreover, they did not have sufficient knowledge of sick days and/or lactic acidosis.

Lactate Levels with Chronic Metformin Use: A Narrative Review

Metformin has been associated with lactic acidosis. Lactate levels are not commonly tested in clinical practice, and it is unclear to what extent metformin would typically increase lactate levels with chronic use. The aim of this review was to determine whether regular monitoring of the plasma lactate level would be beneficial in avoiding lactate accumulation and, ultimately, minimising the incidence of lactic acidosis in metformin-treated patients.A comprehensive search of PubMed, Embase, Web of Science, Cochrane and International Pharmaceutical Abstracts databases covering the period up to 30 May 2017 was performed. Search terms included combinations of terms and keywords, including "metformin", "lactate", "lactic acid" and "lactic acidosis". Cases series of lactic acidosis or metformin-associated lactic acidosis were excluded.Of 1539 potentially relevant articles, a total of 52 reported lactate levels from routine/regular pathological tests in metformin users. The studies were subdivided into four themes, regarding metformin usage and the reported lactate levels in patients who: (1) did not have contraindications to the use of metformin; (2) had contraindications, or renal impairment but without other contraindications; (3) exercised; or (4) also received any nucleoside reverse transcriptase inhibitor. Studies have reported that metformin treatment could increase lactate level of users. However, most results showed that the lactate level remained in the normal range.No definitive conclusions on the benefits of regular lactate monitoring in patients taking metformin can be made. Future research on larger populations focusing on the measurement of lactate levels with continuous metformin use is warranted.

Associations of Polyethylenimine-Coated AN69ST Membrane in Continuous Renal Replacement Therapy with the Intensive Care Outcomes: Observations from a Claims Database from Japan

BACKGROUND/AIMS

Polyethylenimine-coated polyacrylonitrile (AN69ST) membrane is expected to improve the outcomes of critically ill patients treated by continuous renal replacement therapy (CRRT).

METHODS

Using a Japanese health insurance claim database, we identified adult patients receiving CRRT in intensive care units (ICUs) from April 2014 to October 2015. We used a multivariable logistic regression model to assess in-hospital mortality and Fine and Gray's proportional subhazards model to assess the ICU length of stay (ICU-LOS) accounting for the competing risks.

RESULTS

Of 2,469 ICU patients, 156 were treated by AN69ST membrane. Crude in-hospital mortality was 50.0% in the AN69ST group and 54.0% in the non-AN69ST group. Adjusted odds ratio (OR) of AN69ST membrane use for in-hospital mortality was 0.65 (95% CI 0.45-0.93). The use of AN69ST membrane was also independently associated with shorter ICU-LOS.

CONCLUSION

This retrospective observational study suggested that CRRT with AN69ST membrane might be associated with better in-hospital outcomes.

[Metformin impact on purine metabolism in breast cancer]

Large-scale epidemiological and clinical studies have demonstrated the efficacy of metformin in oncology practice. However, the mechanisms of implementation of the anti-tumor effect of this drug there is still need understanding. In this study we have investigated the effect of metformin on the activity of adenosine deaminase and respectively adenosinergic immunosuppression in tumors and their microenvironment. The material of the study was taken during surgery of breast cacer patients receiveing metformin, and also patients which did not take this drug. The adenosine deaminase activity and substrate (adenosine) and products (inosine, hypoxanthine) concentrations were determined by HPLC. Results of this study suggest that metformin significantly alters catabolism of purine nucleotides in the node breast adenocarcinoma tisue. However, the metformin-induced increase in the adenosine deaminase activity is not sufficient to reduce the level of adenosine in cancer tissue. Thus, in metformin treated patients the adenosine concentration remained unchanged, and inosine and hypoxanthine concentration significantly increased.

Risk of disseminated intravascular coagulation in patients with type 2 diabetes mellitus: retrospective cohort study

OBJECTIVES

To determine quantitatively the association between type 2 diabetes mellitus (T2DM) and disseminated intravascular coagulation (DIC).

DESIGN

Retrospective cohort study using a claims database.

SETTING

Medical care institutions representing 9% of all secondary hospitals (acute care hospitals) in Japan.

PARTICIPANTS

In total, 797 324 admissions, comprising 435 354 patients aged 18-79 years at the time of admission, were enrolled between January 2010 and September 2014. All patients were diagnosed with diabetes or admitted to hospitals that provided laboratory data.

MAIN OUTCOME MEASURES

Incidence of DIC reported by physicians in claims data.

RESULTS

Logistic regression analysis found that the risk of DIC was significantly higher in T2DM patients than in non-DM patients (fully adjusted OR: 1.39 (95% CI 1.32 to 1.45)), independent of age, sex, admission year and potential underlying diseases. The higher risk of DIC in T2DM patients was apparent in those who were treated with insulin within the 30-day period prior to admission (1.53 (1.37 to 1.72)). When stratified by the potential underlying diseases, the risk of DIC was higher in T2DM patients with non-septic severe infection (1.67 (1.41 to 1.97)) and with solid tumour (1.59 (1.47 to 1.72)) than in non-DM patients with those underlying diseases. The risk was similar between T2DM and non-DM patients with sepsis (0.98 (0.90 to 1.08)) and lower in T2DM patients with acute leukaemia (0.70 (0.59 to 0.84)).

CONCLUSIONS

T2DM was associated with a higher risk of DIC, particularly when recently treated with insulin, as well as among admissions with solid tumour or non-septic severe infection.

Retrospective analysis of lactic acidosis-related parameters upon and after metformin discontinuation in patients with diabetes and chronic kidney disease

PURPOSE

To investigate association between renal functions, lactic acid levels and acid-base balance in type 2 diabetes patients with chronic kidney disease under metformin treatment and after metformin discontinuation in a real-life setting.

METHODS

A total of 65 patients with diabetes (mean age 68.5 ± 8.9 years, 56.9 % females) in whom metformin treatment was discontinued due to reduced glomerular filtration rate (GFR) were included in this retrospective study. Data on patient demographics, metformin treatment and laboratory findings on the last day of metformin treatment and 2-3 weeks after metformin discontinuation including blood lactate and creatinine, estimated glomerular filtration rate (eGFR) and acid-base balance measurements in blood [pH, bicarbonate, base excess] were collected from medical records. The correlation of lactate levels with eGFR, blood pH and creatinine levels and changes in laboratory findings after metformin discontinuation were evaluated.

RESULTS

Before metformin discontinuation, hyperlactatemia was observed in 78.5 % of patients and metabolic acidosis in 36.9 % of patients, but none had lactic acidosis. Patients with normolactatemia and hyperlactatemia were similar in terms of metformin dosage and laboratory parameters. Lactate levels were not significantly correlated with serum creatinine (r = -0.14; p = 0.263) and eGFR (r = 0.11, p = 0.374). After metformin discontinuation, a significant decrease was observed in median lactate levels (from 2.20 to 1.85 mmol/L; p = 0.002).

CONCLUSION

In conclusion, our findings support the low risk of MALA among patients with mild-to-moderate renal impairment and the likelihood of metformin to be an innocent bystander without a pathogenic role in the lactic acidosis in most cases.

Metformin-associated lactic acidosis: Current perspectives on causes and risk

Although metformin has become a drug of choice for the treatment of type 2 diabetes mellitus, some patients may not receive it owing to the risk of lactic acidosis. Metformin, along with other drugs in the biguanide class, increases plasma lactate levels in a plasma concentration-dependent manner by inhibiting mitochondrial respiration predominantly in the liver. Elevated plasma metformin concentrations (as occur in individuals with renal impairment) and a secondary event or condition that further disrupts lactate production or clearance (e.g., cirrhosis, sepsis, or hypoperfusion), are typically necessary to cause metformin-associated lactic acidosis (MALA). As these secondary events may be unpredictable and the mortality rate for MALA approaches 50%, metformin has been contraindicated in moderate and severe renal impairment since its FDA approval in patients with normal renal function or mild renal insufficiency to minimize the potential for toxic metformin levels and MALA. However, the reported incidence of lactic acidosis in clinical practice has proved to be very low (<10 cases per 100,000 patient-years). Several groups have suggested that current renal function cutoffs for metformin are too conservative, thus depriving a substantial number of type 2 diabetes patients from the potential benefit of metformin therapy. On the other hand, the success of metformin as the first-line diabetes therapy may be a direct consequence of conservative labeling, the absence of which could have led to excess patient risk and eventual withdrawal from the market, as happened with earlier biguanide therapies. An investigational delayed-release metformin currently under development could potentially provide a treatment option for patients with renal impairment pending the results of future studies. This literature-based review provides an update on the impact of renal function and other conditions on metformin plasma levels and the risk of MALA in patients with type 2 diabetes.