Should Restrictions Be Relaxed for Metformin Use in Chronic Kidney Disease? Yes, They Should Be Relaxed! What's the Fuss?

Examining the clinical relevance of metformin as an antioxidant intervention

In physiological concentrations, reactive oxygen species play a vital role in regulating cell signaling and gene expression. Nevertheless, oxidative stress is implicated in the pathogenesis of numerous diseases and can inflict damage on diverse cell types and tissues. Thus, understanding the factors that mitigate the deleterious effects of oxidative stress is imperative for identifying new therapeutic targets. In light of the absence of direct treatment recommendations for reducing oxidative stress, there is a continuing need for fundamental research that utilizes innovative therapeutic approaches. Metformin, known for its multifaceted beneficial properties, is acknowledged for its ability to counteract the adverse effects of increased oxidative stress at both molecular and cellular levels. In this review, we delve into recent insights regarding metformin's antioxidant attributes, aiming to expand its clinical applicability. Our review proposes that metformin holds promise as a potential adjunctive therapy for various diseases, given its modulation of oxidative stress characteristics and regulation of diverse metabolic pathways. These pathways include lipid metabolism, hormone synthesis, and immunological responses, all of which may experience dysregulation in disease states, contributing to increased oxidative stress. Furthermore, our review introduces potential novel metformin-based interventions that may merit consideration in future research. Nevertheless, the necessity for clinical trials involving this drug remains imperative, as they are essential for establishing therapeutic dosages and addressing challenges associated with dose-dependent effects.

The function, mechanisms, and clinical applications of metformin: potential drug, unlimited potentials

Metformin has been used clinically for more than 60 years. As time goes by, more and more miraculous effects of metformin beyond the clinic have been discovered and discussed. In addition to the clinically approved hypoglycemic effect, it also has a positive metabolic regulation effect on the human body that cannot be ignored. Such as anti-cancer, anti-aging, brain repair, cardiovascular protection, gastrointestinal regulation, hair growth and inhibition of thyroid nodules, and other nonclinical effects. Metformin affects almost the entire body in the situation taking it over a long period, and the preventive effects of metformin in addition to treating diabetes are also beginning to be recommended in some guidelines. This review is mainly composed of four parts: the development history of metformin, the progress of clinical efficacy, the nonclinical efficacy of metformin, and the consideration and prospect of its application.

Metformin: Is it a drug for all reasons and diseases?

Metformin was first used to treat type 2 diabetes in the late 1950s and in 2022 remains the first-choice drug used daily by approximately 150 million people. An accumulation of positive pre-clinical and clinical data has stimulated interest in re-purposing metformin to treat a variety of diseases including COVID-19. In polycystic ovary syndrome metformin improves insulin sensitivity. In type 1 diabetes metformin may help reduce the insulin dose. Meta-analysis and data from pre-clinical and clinical studies link metformin to a reduction in the incidence of cancer. Clinical trials, including MILES (Metformin In Longevity Study), and TAME (Targeting Aging with Metformin), have been designed to determine if metformin can offset aging and extend lifespan. Pre-clinical and clinical data suggest that metformin, via suppression of pro-inflammatory pathways, protection of mitochondria and vascular function, and direct actions on neuronal stem cells, may protect against neurodegenerative diseases. Metformin has also been studied for its anti-bacterial, -viral, -malaria efficacy. Collectively, these data raise the question: Is metformin a drug for all diseases? It remains unclear as to whether all of these putative beneficial effects are secondary to its actions as an anti-hyperglycemic and insulin-sensitizing drug, or result from other cellular actions, including inhibition of mTOR (mammalian target for rapamycin), or direct anti-viral actions. Clarification is also sought as to whether data from ex vivo studies based on the use of high concentrations of metformin can be translated into clinical benefits, or whether they reflect a 'Paracelsus' effect. The environmental impact of metformin, a drug with no known metabolites, is another emerging issue that has been linked to endocrine disruption in fish, and extensive use in T2D has also raised concerns over effects on human reproduction. The objectives for this review are to: 1) evaluate the putative mechanism(s) of action of metformin; 2) analyze the controversial evidence for metformin's effectiveness in the treatment of diseases other than type 2 diabetes; 3) assess the reproducibility of the data, and finally 4) reach an informed conclusion as to whether metformin is a drug for all diseases and reasons. We conclude that the primary clinical benefits of metformin result from its insulin-sensitizing and antihyperglycaemic effects that secondarily contribute to a reduced risk of a number of diseases and thereby enhancing healthspan. However, benefits like improving vascular endothelial function that are independent of effects on glucose homeostasis add to metformin's therapeutic actions.

A Comparative Study of Acidosis in Diabetic Advanced Chronic Kidney Disease Patients on and off Metformin

Aim

The aim of the study is to assess the risk of acidosis in diabetic advanced chronic kidney disease (CKD) patients on and off metformin.

Methods

This retrospective descriptive study was conducted in the nephrology department in The Kidney Centre Post Graduate Training Institute (TKC PGTI) Karachi from February to April 2020. We reviewed the records of all patients over 18 years old who visited the nephrology outpatient department in three months in 2020 (from February 2020 to April 2020), who had CKD (stage 2-5), are not on dialysis, and had type 2 diabetes. These were divided into two groups: those on metformin for more than one year and those not on metformin. We looked at hospitalizations due to acidosis in the previous one-year period.

Results

A total of 524 CKD patients had diabetes; out of those, 268 patients were on metformin, and 256 were not on metformin. The male vs. female distribution was 52.1% vs. 47.9%. A total of 114 (21.8%) patients required admission in the previous one-year period, and only 12 hospitalized patients had acidosis, seven (58.3%) were on metformin, and five (41.7%) were not on metformin, which was statistically insignificant.

Conclusion

Biguanides, especially metformin, is a known oral hypoglycemic drug used for decades to treat type 2 diabetes mellitus (DM). Metformin use is related to a rare but serious adverse event, metformin-associated lactic acidosis (MALA), especially in renal failure patients. In our study, metformin use in CKD diabetic patients did not result in more admissions due to acidosis than non-metformin users.

Efficacy of metformin monotherapy in US veterans with type 2 diabetes and preexisting chronic kidney disease stage 3

AIM

To evaluate the glycaemic efficacy of metformin in people with type 2 diabetes (T2D) and stage 3 chronic kidney disease (CKD3).

PARTICIPANTS AND METHODS

This was a retrospective study including 145980 US veterans with T2D and an estimated glomerular filtration rate (eGFR) ≥30 mL/min/1.73 m² who initiated metformin monotherapy between November 1999 and July 2017. Propensity-score-matched cohorts were generated based on baseline variables associated with CKD3 (eGFR 30-59 mL/min/1.73 m² ) to evaluate the independent association between CKD3 and metformin discontinuation, the addition of a second hypoglycaemic agent, and changes in glycated haemoglobin (HbA1c) from baseline in those with and without CKD3. Associations were examined using the Kaplan-Meier method and multivariable regression models, adjusted for baseline and 12-month average metformin dose.

RESULTS

The mean age of the entire cohort was 60.7 years, and 95% of the cohort were men, 21% were African American and 9% had CKD3. In the adjusted analyses, patients with CKD3 had a higher risk of metformin discontinuation or addition of a second hypoglycaemic agent, as compared with patients without CKD (hazard ratio [HR] 1.22, 95% confidence interval [CI] 1.19-1.26, and HR 1.26, 95% CI 1.13-1.40, respectively). Among metformin monotherapy users, there were no differences in the average HbA1c reduction from baseline to 12 or 24 months between patients with and without CKD3.

CONCLUSIONS

Individuals with CKD3 and T2D were at increased risk of metformin monotherapy failure. However, the HbA1c-lowering efficacy of metformin was similar in patients with and without CKD3, highlighting that metformin is a valuable treatment option for newly treated individuals with T2D and CKD3.

A Critical Review of the Evidence That Metformin Is a Putative Anti-Aging Drug That Enhances Healthspan and Extends Lifespan

The numerous beneficial health outcomes associated with the use of metformin to treat patients with type 2 diabetes (T2DM), together with data from pre-clinical studies in animals including the nematode, C. elegans, and mice have prompted investigations into whether metformin has therapeutic utility as an anti-aging drug that may also extend lifespan. Indeed, clinical trials, including the MILES (Metformin In Longevity Study) and TAME (Targeting Aging with Metformin), have been designed to assess the potential benefits of metformin as an anti-aging drug. Preliminary analysis of results from MILES indicate that metformin may induce anti-aging transcriptional changes; however it remains controversial as to whether metformin is protective in those subjects free of disease. Furthermore, despite clinical use for over 60 years as an anti-diabetic drug, the cellular mechanisms by which metformin exerts either its actions remain unclear. In this review, we have critically evaluated the literature that has investigated the effects of metformin on aging, healthspan and lifespan in humans as well as other species. In preparing this review, particular attention has been placed on the strength and reproducibility of data and quality of the study protocols with respect to the pharmacokinetic and pharmacodynamic properties of metformin. We conclude that despite data in support of anti-aging benefits, the evidence that metformin increases lifespan remains controversial. However, via its ability to reduce early mortality associated with various diseases, including diabetes, cardiovascular disease, cognitive decline and cancer, metformin can improve healthspan thereby extending the period of life spent in good health. Based on the available evidence we conclude that the beneficial effects of metformin on aging and healthspan are primarily indirect via its effects on cellular metabolism and result from its anti-hyperglycemic action, enhancing insulin sensitivity, reduction of oxidative stress and protective effects on the endothelium and vascular function.

Lactic acidosis incidence with metformin in patients with type 2 diabetes and chronic kidney disease: A retrospective nested case-control study

Objective

Compare rates of lactic acidosis (LA) among metformin-exposed and unexposed patients with type 2 diabetes mellitus and varying degrees of chronic kidney disease (CKD).

Research Design and Methods

Retrospective, nested case-control study using data from national VA Corporate Data Warehouse. All adult patients with type 2 diabetes and CKD newly dispensed any antihyperglycaemic medication during FY 2003-13 were included. The outcome was LA hospitalization or serum lactate >5 mEq/L. Exposure to metformin was evaluated in the three months prior to event. Estimates were adjusted for 31 covariates, including demographics, comorbidities and medications.

Results

Overall, 320 882 patients were included, contributing a total of 1 331 784 person-years of follow-up. LA occurred in 2 665 patients, generating an overall incidence rate of 2.00 (95% CI 1.93-2.08) per 1000 person-years. Metformin exposure in the prior 3 months was associated with an elevated adjusted hazard of LA (HR 1.97, 95% CI 1.69-2.29). No association was evident in patients with CKD stage 1 or 2 (HR 1.05, 95% CI 0.71-1.57), but associations were present and progressively greater in patients with CKD stage 3a through 5: HR 3.09, 95% CI 2.19-4.35 in CKD 3a, HR 3.34, 95% CI 1.95-5.72 in CKD 3b, HR 7.87, 95% CI 3.51-17.61 in CKD stage 4&5.

Conclusion

Metformin was not associated with an elevated risk of LA in persons with stage 1-2 CKD, but was associated with a progressively higher risk at more advanced stages of CKD.

Benefits of Metformin in Attenuating the Hallmarks of Aging

Biological aging involves an interplay of conserved and targetable molecular mechanisms, summarized as the hallmarks of aging. Metformin, a biguanide that combats age-related disorders and improves health span, is the first drug to be tested for its age-targeting effects in the large clinical trial-TAME (targeting aging by metformin). This review focuses on metformin's mechanisms in attenuating hallmarks of aging and their interconnectivity, by improving nutrient sensing, enhancing autophagy and intercellular communication, protecting against macromolecular damage, delaying stem cell aging, modulating mitochondrial function, regulating transcription, and lowering telomere attrition and senescence. These characteristics make metformin an attractive gerotherapeutic to translate to human trials.

A Safety Comparison of Metformin vs Sulfonylurea Initiation in Patients With Type 2 Diabetes and Chronic Kidney Disease: A Retrospective Cohort Study

OBJECTIVE

To compare the safety of metformin vs sulfonylureas in patients with type 2 diabetes by chronic kidney disease (CKD) stage.

PATIENTS AND METHODS

This retrospective cohort study included adults in Manitoba, Canada, with type 2 diabetes, an incident monotherapy prescription for metformin or a sulfonylurea, and a serum creatinine measurement from April 1, 2006, to March 31, 2017. Patients were stratified by estimated glomerular filtration rate (eGFR) into the following groups: eGFR of 90 or greater, 60 to 89, 45 to 59, 30 to 44, or less than 30 mL/min/1.73 m². Outcomes included all-cause mortality, cardiovascular events, and major hypoglycemic episodes. Baseline characteristics were used to calculate propensity scores and perform inverse probability of treatment weights analysis, and eGFR group was examined as an effect modifier for each outcome.

RESULTS

The cohort consisted of 21,996 individuals (19,990 metformin users and 2006 sulfonylurea users). Metformin use was associated with lower risk for all-cause mortality (hazard ratio [HR], 0.48; 95% CI, 0.40-0.58; P<.001), cardiovascular events (HR, 0.67; 95% CI, 0.52-0.86; P=.002), and major hypoglycemic episodes (HR, 0.14; 95% CI, 0.09-0.20; P<.001) when compared with sulfonylureas. CKD was a significant effect modifier for all-cause mortality (P=.002), but not for cardiovascular events or major hypoglycemic episodes.

CONCLUSION

Sulfonylurea monotherapy is associated with higher risk for all-cause mortality, major hypoglycemic episodes, and cardiovascular events compared with metformin. Although the presence of CKD attenuated the mortality benefit, metformin may be a safer alternative to sulfonylureas in patients with CKD.

Metformin as Anti-Aging Therapy: Is It for Everyone?

Metformin is the most widely prescribed oral hypoglycemic medication for type 2 diabetes worldwide. Metformin also retards aging in model organisms and reduces the incidence of aging-related diseases such as neurodegenerative disease and cancer in humans. In spite of its widespread use, the mechanisms by which metformin exerts favorable effects on aging remain largely unknown. Further, not all individuals prescribed metformin derive the same benefit and some develop side effects. Before metformin finds its way to mainstay therapy for anti-aging, a more granular understanding of the effects of the drug in humans is needed. This review provides an overview of recent findings from metformin studies in aging and longevity and discusses the use of metformin to combat aging and aging-related diseases.

Use of Insulin in the Inpatient Setting: Need for Continued Use

PURPOSE OF REVIEW

Insulin has been the standard of care for the management of inpatient diabetes for achieving strict glycemic control. This review supports continuing insulin therapy for hyperglycemic management in the hospital compared with the use of non-insulin treatment regimens.

RECENT FINDINGS

Oral hypoglycemic agents and glucagon-like peptide 1 (GLP-1) receptor agonists have typically not been used in the inpatient setting. Recent studies regarding DPP-4 inhibitors have led to variable results with fairly high glycemic values during the hospitalization. Similarly, studies looking at GLP-1 receptor agonists are limited, but gastrointestinal side effects limit their inpatient use. Overall, there is a paucity of data to support the use of non-insulin-based therapy in the inpatient setting. Insulin has repeatedly demonstrated that its advantageous quality of being easily titratable leads to more consistently efficacious glycemic control that improves morbidity and mortality.

Type 2 diabetes treatment and progression of chronic kidney disease in Italian family practice

AIMS

Progressive chronic kidney disease represents a dreadful complication of type 2 diabetes mellitus (T2DM). We tested the pattern of use and the renal effects of old glucose-lowering drugs in T2DM patients cared for by Italian general practitioners (GPs).

METHODS

Data of 2606 T2DM patients were extracted from the databases of GPs, who do not have access to the most recent glucose-lowering drugs in Italy. The rate of kidney function decline was calculated by CKD-EPIcr, based on two consecutive creatinine values.

RESULTS

Metformin was used in 55% of cases, either alone or with sulfonylureas/repaglinide, across the whole spectrum of CKD (from 66% in stage G1 to only 8% in G4). Sulfonylurea use peaked at 21-22% in stage G2-G3a, whereas repaglinide use significantly increased from 8% in G1 to 22% in G4. The median rate of CKD decline was - 1.64 mL/min/1.73 m2 per year; it was higher in G1 (- 3.22 per year) and progressively lower with CKD severity. 826 cases (31.7%) were classified as fast progressors (eGFR decline more negative than - 5 mL/min/1.73 m2 per year). The risk of fast progressing CKD was associated with increasing BMI, albuminuria, and sulfonylurea use, alone (OR, 1.47; 95% confidence interval, 1.16-1.85), or in association with metformin (OR, 1.40; 95% CI 1.04-1.88). No associations were demonstrated for metformin, cardiovascular and lipid lowering drug use.

CONCLUSION

In the setting of Italian family practice, sulfonylurea use is associated with progressive CKD in patients with T2DM. Metformin, at doses progressively reduced according to CKD stages, as recommended by guidelines, is not associated with fast progression.

Treatment of Diabetes in Older Adults: An Endocrine Society* Clinical Practice Guideline

OBJECTIVE

The objective is to formulate clinical practice guidelines for the treatment of diabetes in older adults.

CONCLUSIONS

Diabetes, particularly type 2, is becoming more prevalent in the general population, especially in individuals over the age of 65 years. The underlying pathophysiology of the disease in these patients is exacerbated by the direct effects of aging on metabolic regulation. Similarly, aging effects interact with diabetes to accelerate the progression of many common diabetes complications. Each section in this guideline covers all aspects of the etiology and available evidence, primarily from controlled trials, on therapeutic options and outcomes in this population. The goal is to give guidance to practicing health care providers that will benefit patients with diabetes (both type 1 and type 2), paying particular attention to avoiding unnecessary and/or harmful adverse effects.

Pharmacotherapy of type 2 diabetes in patients with chronic liver disease: focus on nonalcoholic fatty liver disease

INTRODUCTION

Pharmacotherapy used to treat type 2 diabetes mellitus (T2DM) is facing a paradigm shift in clinical practice with recent cardiovascular (CV) outcome trials having a substantial impact on drug prescription with treatment having a more tailored approach. In patients with T2DM, the issue of chronic liver disease is multifaceted. However, a clinical evidence is emerging on the beneficial effect of antidiabetic medications on nonalcoholic fatty liver disease (NAFLD).

AREAS COVERED

The authors provide a synopsis on the current and upcoming pharmacotherapy for NAFLD, including the challenges with their development, focusing on drugs for T2DM. Clinical data on the potential benefits and safety issues are assessed with the aim of proposing an individualized algorithm for patient management. Both MEDLINE and ClinicalTrials.Gov are used to derive the relevant information.

EXPERT OPINION

Considering the pivotal role of insulin resistance in NAFLD, insulin sensitizers should be the treatment of choice. Accordingly, pioglitazone is the only drug with a significant effect on liver fibrosis, the driver of disease progression and long-term outcome. Among new glucose-lowering drugs, glucagon-like-peptide 1 receptor agonists or sodium-glucose cotransporter type 2 inhibitors have shown positive effects in phase II studies and are qualifying as potential candidates for NAFLD treatment in diabetes.

Hypoglycemia-Related Hospitalizations and Mortality Among Patients With Diabetes Transitioning to Dialysis

RATIONALE & OBJECTIVE

Diabetic patients with declining kidney function are at heightened risk for hypoglycemia. We sought to determine whether hypoglycemia-related hospitalizations in the interval before dialysis therapy initiation are associated with post-end-stage renal disease (ESRD) mortality among incident patients with ESRD with diabetes.

STUDY DESIGN

Observational cohort study.

SETTING & PARTICIPANTS

US veterans from the national Veterans Affairs database with diabetes and chronic kidney disease transitioning to dialysis therapy from October 2007 to September 2011.

EXPOSURE

Hypoglycemia-related hospitalizations during the pre-ESRD period and antidiabetic medication regimens.

OUTCOME

The outcome of post-ESRD all-cause mortality was evaluated relative to pre-ESRD hypoglycemia. The outcome of pre-ESRD hypoglycemia-related hospitalization was evaluated relative to antidiabetic medication regimens.

ANALYTIC APPROACH

We examined whether the occurrence and frequency of pre-ESRD hypoglycemia-related hospitalizations are associated with post-ESRD mortality using Cox regression models adjusted for case-mix covariates. In a subcohort of patients prescribed 0 to 2 oral antidiabetic drugs and/or insulin, we examined the 12 most commonly prescribed antidiabetic medication regimens and risk for pre-ESRD hypoglycemia-related hospitalization using logistic regression models adjusted for case-mix covariates.

RESULTS

Among 30,156 patients who met eligibility criteria, the occurrence of pre-ESRD hypoglycemia-related hospitalization(s) was associated with higher post-ESRD mortality risk: adjusted HR (aHR), 1.25; 95% CI, 1.17-1.34 (reference group: no hypoglycemia hospitalization). Increasing frequency of hypoglycemia-related hospitalizations was independently associated with incrementally higher mortality risk: aHRs of 1.21 (95% CI, 1.12-1.30), 1.47 (95% CI, 1.19-1.82), and 2.07 (95% CI, 1.46-2.95) for 1, 2, and 3 or more hypoglycemia-related hospitalizations, respectively (reference group: no hypoglycemia hospitalization). Compared with patients who were prescribed neither oral antidiabetic drugs nor insulin, medication regimens that included sulfonylureas and/or insulin were associated with higher risk for hypoglycemia.

LIMITATIONS

Residual confounding cannot be excluded.

CONCLUSIONS

Among incident patients with ESRD with diabetes, a dose-dependent relationship between frequency of pre-ESRD hypoglycemia-related hospitalizations and post-ESRD mortality was observed. Further study of diabetic management strategies that prevent hypoglycemia as patients with chronic kidney disease transition to ESRD are warranted.

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.

Patient-factors associated with metformin steady-state levels in type 2 diabetes mellitus with therapeutic dosage

AIMS

This prospective study aimed to analyze metformin steady-state concentration in repeated constant dosage and the influencing patient-factors as well as to correlate them with glycemic control.

METHODS

The validated HPLC-UV method was used to examine metformin steady-state concentration, while FBG and glycated albumin were used as the parameters of glycemic control during metformin administration.

RESULTS

A total of 82 type-2 diabetes patients were involved with 32.1% of them having metformin Cssmin and 84.1% having Cssmax of metformin within the recommended therapeutic range. One patient had metformin Css that exceeded minimum toxic concentration despite his normal renal function and administered therapeutic dosage of metformin. Higher Cssmax was found in patients with metformin monotherapy, while patients with longer duration of metformin use had significantly higher Cssmin.

CONCLUSIONS

Along with initial hyperglycemia and eGFR, metformin Cssmin became the only parameter that influenced FBG level (P < 0.05). Duration of previous metformin use should be considered in the strategy of optimizing metformin dosage. The type-2 diabetes patients with obesity are more suggested to take shorter interval of metformin administration (or possibly with sustained-release formulation) to keep Cssmin within the therapeutic range.

Which treatment for type 2 diabetes associated with non-alcoholic fatty liver disease?

Type 2 diabetes (T2DM) and nonalcoholic fatty liver disease (NAFLD) are highly prevalent in the community, and share common pathogenic mechanisms. There is also evidence that T2DM may be favored by hepatic fat accumulation; in turn the presence of T2DM is a risk factor for liver disease progression. The treatment of T2DM has considerably changed in the past few years; new drug classes, promoting glucose-lowering through mechanisms different from classical insulin-sensitizing or insulin-secreting action, have been added to continuing lifestyle intervention. Metformin and pioglitazone may be safely used in the presence of liver fat, whereas sulfonylureas and insulin itself have been associated with NAFLD progression and adverse outcome. Drugs acting on the incretin axis and on Na-glucose co-transport at renal tubular level offer new hopes for a tailored treatment able to reduce the burden of hepatic triglyceride accumulation and liver disease progression.