Effectiveness and safety of metformin in 51 675 patients with type 2 diabetes and different levels of renal function: a cohort study from the Swedish National Diabetes Register

Clinical Outcomes of Metformin Use in Populations With Chronic Kidney Disease, Congestive Heart Failure, or Chronic Liver Disease: A Systematic Review

BACKGROUND

Recent changes to the U.S. Food and Drug Administration boxed warning for metformin will increase its use in persons with historical contraindications or precautions. Prescribers must understand the clinical outcomes of metformin use in these populations.

PURPOSE

To synthesize data addressing outcomes of metformin use in populations with type 2 diabetes and moderate to severe chronic kidney disease (CKD), congestive heart failure (CHF), or chronic liver disease (CLD) with hepatic impairment.

DATA SOURCES

MEDLINE (via PubMed) from January 1994 to September 2016, and Cochrane Library, EMBASE, and International Pharmaceutical Abstracts from January 1994 to November 2015.

STUDY SELECTION

English-language studies that: 1) examined adults with type 2 diabetes and CKD (with estimated glomerular filtration rate less than 60 mL/min/1.73 m2), CHF, or CLD with hepatic impairment; 2) compared diabetes regimens that included metformin with those that did not; and 3) reported all-cause mortality, major adverse cardiovascular events, and other outcomes of interest.

DATA EXTRACTION

2 reviewers abstracted data and independently rated study quality and strength of evidence.

DATA SYNTHESIS

On the basis of quantitative and qualitative syntheses involving 17 observational studies, metformin use is associated with reduced all-cause mortality in patients with CKD, CHF, or CLD with hepatic impairment, and with fewer heart failure readmissions in patients with CKD or CHF.

LIMITATIONS

Strength of evidence was low, and data on multiple outcomes of interest were sparse. Available studies were observational and varied in follow-up duration.

CONCLUSION

Metformin use in patients with moderate CKD, CHF, or CLD with hepatic impairment is associated with improvements in key clinical outcomes. Our findings support the recent changes in metformin labeling.

PRIMARY FUNDING SOURCE

U.S. Department of Veterans Affairs. (PROSPERO: CRD42016027708).

Evaluating beneficial drug effects in a non-interventional setting: a review of effectiveness studies based on Swedish Prescribed Drug Register data

Aims

To describe and assess current effectiveness studies published up to 2014 using Swedish Prescribed Drug Register (SPDR) data.

Methods

Study characteristics were extracted. Each study was assessed concerning the clinical relevance of the research question, the risk of bias according to a structured checklist, and as to whether its findings contributed to new knowledge. The biases encountered and ways of handling these were retrieved.

Results

A total of 24 effectiveness studies were included in the review, the majority on cardiovascular or psychiatric disease (n = 17; 71%). The articles linked data from four (interquartile range: three to four) registers, and were published in 21 different journals with an impact factor ranging from 1.58 to 51.66. All articles had a clinically relevant research question. According to the systematic quality assessments, the overall risk of bias was low in one (4%), moderate in eight (33%) and high in 15 (62%) studies. Overall, two (8%) studies were assessed as contributing to new knowledge. Frequently occurring problems were selection bias making the comparison groups incomparable, treatment bias with suboptimal handling of drug exposure and an intention‐to‐treat approach, and assessment bias including immortal time bias. Good examples of how to handle bias problems included propensity score matching and sensitivity analyses.

Conclusion

Although this review illustrates that effectiveness studies based on dispensed drug register data can contribute to new evidence of intended effects of drug treatment in clinical practice, the expectations of such data to provide valuable information need to be tempered due to methodological issues.

Provider Decisions and Patient Outcomes After Premature Metformin Discontinuation

The purpose of this study was to evaluate the effects of alternative antihyperglycemic therapy after discontinuation of metformin due to documented declining renal function. This retrospective, single-site study evaluated patients who had metformin discontinued between 1 January 1999 and 30 September 2013. Medical records were evaluated for documented adverse events, subsequent glycemic control, and costs associated with the alternative therapy. Patients served as their own controls. A total of 179 patients met study entry criteria, and their peak A1C was significantly higher within the year after metformin discontinuation (P <0.001). After the provider added new medications to control patients' blood glucose, their A1C by the end of the first year after discontinuing metformin was similar to their A1C while taking metformin. Significant weight gain accompanied the use of the medications added to replace metformin, with an average increase of 3.81 kg (P <0.001). Additionally, after discontinuing metformin, more patients experienced hypoglycemia with the addition of other medications to control their blood glucose (P <0.001). As expected, the cost of therapy was significantly higher (P <0.0001) after metformin was discontinued because metformin was generically available, whereas the replacement medications frequently were not. Providers should consider the expanded recommendations for the use of metformin in patients with mild to moderate stable renal dysfunction to help such patients avoid weight gain, hypoglycemia, loss of blood glucose control, and increased costs.

Are all people with diabetes and cardiovascular risk factors or microvascular complications at very high risk? Findings from the Risk and Prevention Study

AIMS

To verify whether it is possible, in people with diabetes mellitus (DM) considered at very high cardiovascular (CV) risk, stratify this risk better and identify significant modifiable risk factor (including lifestyle habits) to help patients and clinicians improve CV prevention.

METHODS

People with DM and microvascular diseases or one or more CV risk factors (hypertension, hyperlipidemia, smoking, poor dietary habits, overweight, physical inactivity) included in the Risk and Prevention study were selected. We considered the combined endpoint of non-fatal acute myocardial infarction and stroke and CV death. A multivariate Cox proportional analysis was carried out to identify relevant predictors. We also used the RECPAM method to identify subgroups of patients at higher risk.

RESULTS

In our study, the rate of major CV events was lower than expected (5 % in 5 years). Predictors of CV events were age, male, sex, heart failure, previous atherosclerotic disease, atrial fibrillation, insulin treatment, high HbA1c, heart rate and other CV diseases while being physically active was protective. RECPAM analysis indicated that history of atherosclerotic diseases and a low BMI defined worse prognosis (HR 4.51 95 % CI 3.04-6.69). Among subjects with no previous atherosclerotic disease, men with HbA1c more than 8 % were at higher CV risk (HR 2.77; 95 % CI 1.86-4.14) with respect to women.

CONCLUSIONS

In this population, the rate of major CV events was lower than expected. This prediction model could help clinicians identify people with DM at higher CV risk and support them in achieving goals of physical activity and HbA1c.

Could metformin be used in patients with diabetes and advanced chronic kidney disease?

Diabetes is an important cause of end stage renal failure worldwide. As renal impairment progresses, managing hyperglycaemia can prove increasingly challenging, as many medications are contra-indicated in moderate to severe renal impairment. Whilst evidence for tight glycaemic control reducing progression to renal failure in patients with established renal disease is limited, poor glycaemic control is not desirable, and is likely to lead to progressive complications. Metformin is a first-line therapy in patients with Type 2 diabetes, as it appears to be effective in reducing diabetes related end points and mortality in overweight patients. Cessation of metformin in patients with progressive renal disease may not only lead to deterioration in glucose control, but also to loss of protection from cardiovascular disease in a cohort of patients at particularly high risk. We advocate the need for further study to determine the role of metformin in patients with severe renal disease (chronic kidney disease stage 4-5), as well as patients on dialysis, or pre-/peri-renal transplantation. We explore possible roles of metformin in these circumstances, and suggest potential key areas for further study.

Investigation of Risk Factors Affecting Lactate Levels in Japanese Patients Treated with Metformin

Metformin is a biguanaide antidiabetic drug used worldwide, and its effectiveness and benefits have already been established. However, the safety of high doses of metformin in Japanese patients, especially in elderly patients with a decreased renal function, remains unclear. Among the side effects of metformin, lactate acidosis is the most problematic due to a high mortality rate. Therefore, we assessed plasma lactate levels in metformin-treated patients to identify independent risk factors for hyperlactemia. 290 outpatients receiving various doses of metformin at our hospital were enrolled between March and July 2014. Serum electrolytes, Cre (creatinine), BUN (blood urea nitrogen), UA (uric acid), HbA1c (hemoglobin A1c), and lactate levels were investigated. Lactate levels did not significantly differ between the elderly (≥75 years) and non-elderly (<75 years) groups. Patients in the elderly group had a significantly lower daily metformin dose and estimated glomerular filtration rate (eGFR), compared with the non-elderly group (both p<0.005). Between with and without hyperlactemia groups, no significant differences were observed in either Cre or age. On the other hand, patients with hyperlactemia had a significantly higher dose of metformin than those without hyperlactemia (p<0.05). In this study, we found that old age and mildly impaired kidney function were not associated with increased lactate levels, and that a higher dose of metformin may be an independent risk factor for elevated lactate levels in Japanese patients.

Metformin: New Preparations and Nonglycemic Benefits

Metformin has been widely used for over 5 decades. New preparations have been developed for possible enhancement of efficiency, tolerability, and pleiotropic nonglycemic effects. Extended-release metformin has contributed to adherence and improved gastrointestinal tolerability. Delayed-release metformin acts in the lower gastrointestinal tract and exerts glucose-lowering effects at lower plasma metformin levels, which might suggest use of this biguanide in patients with chronic kidney disease. Metformin is also known to have numerous nonglycemic effects. Results of the UK Prospective Diabetes Study indicate improvements in cardiovascular outcome and reduced total mortality independent of glycemic control. Anticancer effects of metformin have been discussed and many clinical trials are on-going. Metformin is noted for its beneficial effects on lifespan extension and on disorders due to increased insulin resistance. Further investigations, including randomized control trials in nondiabetic individuals, are required to demonstrate the nonglycemic effects of metformin.

Risks of Metformin in Type 2 Diabetes and Chronic Kidney Disease: Lessons Learned from Taiwanese Data

Like other biguanide agents, metformin is an anti-hyperglycemic agent with lower tendency towards hypoglycemia compared to other anti-diabetic drugs. Given its favorable effects on serum lipids, obese body habitus, cardiovascular disease, and mortality, metformin is recommended as the first-line pharmacologic agent for type 2 diabetes in the absence of contraindications. However, as metformin accumulation may lead to type B non-hypoxemic lactic acidosis, especially in the setting of kidney injury, chronic kidney disease, and overdose, regulatory agencies such as the United States Food and Drug Administration (FDA) have maintained certain restrictions regarding its use in kidney dysfunction. Case series have demonstrated a high fatality rate with metformin-associated lactic acidosis (MALA), and the real-life incidence of MALA may be underestimated by observational studies and clinical trials that have excluded patients with moderate-to-advanced kidney dysfunction. A recent study of advanced diabetic kidney disease patients in Taiwan in Lancet Endocrinology and Diabetes has provided unique insight into the potential consequences of unrestricted metformin use, including a 35% higher adjusted mortality risk that was dose-dependent. This timely study, as well as historical data documenting the toxicities of other biguanides, phenformin and buformin, suggest that the recent relaxation of FDA recommendations to expand metformin use in patients with kidney dysfunction (i.e., those with estimated glomerular filtration rates ≥30 instead of our recommended ≥45 ml/min/1.73 m2) may be too liberal. In this article, we will review the history of metformin use; its pharmacology, mechanism of action, and potential toxicities; and policy-level changes in its use over time.

Cardiovascular safety of glucose-lowering agents as add-on medication to metformin treatment in type 2 diabetes: report from the Swedish National Diabetes Register

AIM

To investigate the relative safety of various glucose-lowering agents as add-on medication to metformin in type 2 diabetes in an observational study linking five national health registers.

RESEARCH DESIGN AND METHODS

Patients with type 2 diabetes who had been on metformin monotherapy and started another agent in addition to metformin were eligible for inclusion. The study period was 2005-2012. Adjusted hazard ratios (HRs) with 95% confidence intervals (CIs) of mortality, cardiovascular disease (CVD), coronary heart disease (CHD), stroke and congestive heart failure (CHF) were estimated using Cox proportional hazards models, weighted for a propensity score.

RESULTS

Of the 20 422 patients included in the study, 43% started on second-line treatment with sulphonylurea (SU), 21% basal insulin, 12% thiazolidinedione (TZD), 11% meglitinide, 10% dipeptidyl peptidase-4 (DPP-4) inhibitor, 1% glucagon-like peptide-1 (GLP-1) receptor agonist and 1% acarbose. At the index date, the mean patient age was ~60 years for all groups except the GLP-1 receptor agonist (56.0 years) and SU (62.9 years) groups. Diabetes duration and glycated haemoglobin levels were similar in all groups. When compared with SU, basal insulin was associated with an 18% higher risk and TZD with a 24% lower risk of mortality [HR 1.18 (95% CI 1.03-1.36) and 0.76 (95% CI 0.62-0.94)], respectively. DPP-4 inhibitor treatment was associated with significantly lower risks of CVD, fatal CVD, CHD, fatal CHD and CHF.

CONCLUSIONS

This nationwide observational study showed that second-line treatment with TZD and DPP-4 inhibitor as add-on medication to metformin were associated with significantly lower risks of mortality and cardiovascular events compared with SU, whereas basal insulin was associated with a higher risk of mortality.

Metformin and other glucose-lowering drug initiation and rates of community-based antibiotic use and hospital-treated infections in patients with type 2 diabetes: a Danish nationwide population-based cohort study

OBJECTIVE

Data on early risk of infection in patients receiving their first treatment for type 2 diabetes are limited. We examined rates of community-based antibiotic use and hospital-treated infection in initiators of metformin and other glucose-lowering drugs (GLDs).

DESIGN

Population-based cohort study using medical databases.

SETTING

General practice and hospitals in Denmark.

PARTICIPANTS

131 949 patients with type 2 diabetes who initiated pharmacotherapy with a GLD between 2005 and 2012.

EXPOSURE

Initial GLD used for pharmacotherapy.

MAIN OUTCOME MEASURES

We computed rates and adjusted HRs of community-based antibiotic use and hospital-treated infection associated with choice of initial GLD with reference to metformin initiation, using an intention-to-treat approach.

RESULTS

The rate of community-based antibiotic use was 362 per 1000 patient-years at risk (PYAR) and that for hospital-treated infection was 51 per 1000 PYAR. Compared with metformin, the risk of hospital-treated infection was slightly higher in sulfonylurea initiators (HR 1.12, 95% CI 1.08 to 1.16) and substantially higher in insulin initiators (HR 1.63, 95% CI 1.54 to 1.72) initiators after adjustment for comorbid conditions, comedications and other confounding factors. In contrast, virtually no difference was observed for overall community-based antibiotic use (HR 1.02, 95% CI 1.01 to 1.04, for sulfonylurea initiators; and 1.04, 95% CI 1.01 to 1.07, for insulin initiators).

CONCLUSIONS

Rates of community-based antibiotic treatment and hospitalisation for infection were high in patients receiving their first treatment for type 2 diabetes and differed with the choice of initial GLD used for pharmacotherapy.

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

Metformin is and has been considered as first-line therapy for type 2 diabetes for over a quarter of a century. Like other biguanides, metformin can cause a lactic acidosis that is exceptionally rare but fatal. The likelihood of metformin-associated lactic acidosis is substantially higher in patients with kidney impairment and also among those with seemingly normal kidney function who are at risk of acute kidney injury (AKI). Hence, regulatory agencies in many industrialized nations have maintained strict renal restrictions surrounding metformin. However, there have been millions of people exposed to metformin for many years, many of them with serum creatinine values at or close to 1.5 mg/dL with estimated glomerular filtration rates (eGFRs) much below 60 mL/min/1.73 m(2) who have not developed lactic acidosis. Thus, there clearly remains controversy in this area, and there has been heightened pressure to remove the renal restrictions of metformin. To provide a discussion on the pros and cons of relaxing the renal restrictions for metformin use, we provide a Point-Counterpoint. In the preceding point narrative, Drs. Kalantar-Zadeh and Kovesdy provide their argument that although there is little evidence of the potential benefits of metformin in kidney disease, just considering the sheer numbers of metformin users and the high fatality rate of its associated lactic acidosis, the most appropriate practice is to avoid metformin use in people with eGFR <45 mL/min/1.73 m(2) or in those who are at high risk of AKI irrespective of underlying eGFR. In the counterpoint narrative below, Drs. Bakris and Molitch argue that the data from a very large analysis demonstrate clearly that serum creatinine should be supplanted with eGFR as the criteria for metformin use and that the incidence of lactic acidosis is only elevated in those with a reduced eGFR who become dehydrated for various reasons or in those exposed to some toxin resulting in AKI. Otherwise the data clearly support the use of metformin under normal circumstances down to eGFR >30 mL/min/1.73 m(2)-William T. CefaluEditor in Chief, Diabetes Care.

Heart healthy equals prostate healthy and statins, aspirin, and/or metformin (S.A.M.) are the ideal recommendations for prostate cancer prevention

Cardiovascular disease (CVD) has been the number one cause of death in the U.S. for 114 of the last 115 years. Lifestyle factors that promote CVD also appear to increase prostate cancer risk and those that reduce CVD risk also appear to reduce the risk of prostate cancer. The largest randomized trials utilizing dietary supplements or pharmacologic agents for prostate cancer prevention (Selenium and Vitamin E Cancer Prevention Trial [SELECT]) have also shed light on the problems and future solutions in this area. Dietary supplements that have not been found to be CVD protective, such as selenium and Vitamin E have not been found to be prostate protective. In addition, over exposure to specific anti-oxidants in nutritionally replete populations may be encouraging cancer growth. Future trials of dietary supplements to prevent prostate cancer could be problematic because by the time a definitive trial is initiated the participants will no longer be “deficient” in the nutrient being tested, which arguably occurred in the SELECT trial. It is also interesting that statins, aspirin, and/or metformin (S.A.M.) are 3 generic, low-cost, heart healthy agents derived from natural sources with separate mechanism of actions, which all appear to have the best benefit to risk ratio compared to any other agent available for prostate cancer prevention, especially aggressive disease, or as an ancillary agent (s) to conventional cancer treatment. It is time to focus on the forest over the trees and recommend proven CVD protective measures for men concerned about their risk of prostate cancer.

Secular trends in antihyperglycaemic medication prescriptions in older adults with diabetes and chronic kidney disease: 2004-2013

AIM

To examine how antihyperglycaemic medications were prescribed to older adults with diabetes and chronic kidney disease over the last decade.

METHODS

We conducted a population-based study of 144 252 older adults with diabetes and chronic kidney disease (estimated glomerular filtration rate <60 ml/min/1.73 m(2) or receiving chronic dialysis) in Ontario, Canada. In each study quarter (3-month intervals from 1 April 2004 until 31 March 2013) we studied the proportion of treated and newly treated patients prescribed insulin, sulphonylureas, α-glucosidase inhibitors, metformin, thiazolidinediones, meglitinides and dipeptidyl peptidase-4 (DPP-4) inhibitors. We further examined prescription trends by stage of chronic kidney disease.

RESULTS

The mean age of patients increased slightly (from 76 to 78 years) over the study period and the percentage with comorbidities declined. Metformin was the predominant therapy prescribed (prescribed to a mean of 56.1% of treated patients). Glyburide (glibenclamide) and thiazolidinedione prescriptions decreased (glyburide prescriptions declined from 45.5 to 9.5%, rosiglitazone from 3.6 to 0.2% and pioglitazone from 1.9 to 1.7%), while gliclazide and DPP-4 inhibitor prescriptions increased (gliclazide prescriptions increased from 0.6 to 26.4%, sitagliptin from 0 to 15.3% and saxagliptin from 0 to 2.0%). Up to 48.6% of patients with stage 3a-5 chronic kidney disease or receiving chronic dialysis were prescribed glyburide, and up to 27.6% of patients with stage 4-5 disease or receiving chronic dialysis were prescribed metformin.

CONCLUSIONS

In patients with chronic kidney disease, there were trends towards safer antihyperglycaemic medication prescribing. A considerable number of patients, however, continue to receive medications that should be avoided.

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.

Therapy: Risk of metformin use in patients with T2DM and advanced CKD

In a new study published in The Lancet Diabetes & Endocrinology, metformin use is associated with significantly increased all-cause mortality in patients with type 2 diabetes mellitus and stage 5 chronic kidney disease (CKD). The findings support current recommendations that metformin should not be used in patients with stage 5 CKD.

Association between Use of Oral Anti-Diabetic Drugs and the Risk of Sepsis: A Nested Case-Control Study

Although oral antidiabetic drugs (OADs) have been associated with immunomodulation in preclinical studies, little is still known about the association between the use of OADs and the risk of sepsis. Using a cohort of patients, extracted from Taiwan's National Health Insurance Research Database, with type 2 diabetes who were newly diagnosed between 2010 and 2012 and treated with OADs, we conducted a nested case-control study involving 43,015 cases (patients who were first hospitalized for sepsis) and 43,015 matched controls. Compared with non-use, metformin use was associated with a decreased risk of developing sepsis (adjusted odds ratio [OR] 0.80, 95% confidence interval [CI] 0.77-0.83, P < 0.001), but meglitinide (adjusted OR 1.32, 95% CI 1.25-1.40, P < 0.001) use was associated with the increased risk of developing sepsis. The risk for development of sepsis was also lower among current (adjusted OR 0.87, 95% CI 0.78-0.96) and recent (adjusted OR 0.83, 95% CI 0.73-0.94) thiazolidinedione users. Current or recent sulfonylurea use and dipeptidyl peptidase-4 inhibitor use were not significantly associated with the development of sepsis. Our results highlight the need to consider the potential pleiotropic effect of OADs against sepsis in addition to the lowering of blood glucose.

Treating patients with diabetes of long duration: GLP-1 receptor agonists and insulin in combination

Patients with long-standing type 2 diabetes mellitus (T2DM) can be clinically challenging for physicians to treat because these patients often lack sufficient β-cell function to respond to some oral glucose-lowering agents, may have profound comorbidities, and may have renal impairment that limits the use of traditional agents. These complications, in addition to older age, also increase the risk of hypoglycemia, which can be a major barrier to treatment success. Individualizing treatment targets to balance the benefits of glycemic control with risks of hypoglycemia is the first step to successfully treating these patients. Careful selection of combination therapy strategies to address limited β-cell function, renal function, and cardiovascular status, along with attention to selection of agents associated with lower risk of hypoglycemia, is important. Basal insulin analogs are often used in patients with long-standing diabetes to address insulinopenic states. Incretin-based therapies, particularly GLP-1 receptor agonists, provide postprandial control with lower risks of hypoglycemia than prandial insulin. The author discusses the management of patients with long-standing diabetes who may have limited β-cell function and require transition to insulin therapy with gradual intensification.

Metformin use and mortality in patients with advanced chronic kidney disease: national, retrospective, observational, cohort study

BACKGROUND

Metformin is recommended as a first-line treatment for patients with type 2 diabetes. However, use of this drug has been contraindicated in individuals with impaired kidney function because of the perceived risk of lactic acidosis. Evidence now supports cautious use of metformin in people with mild-to-moderate chronic kidney disease. However, studies examining the use of metformin in patients with advanced chronic kidney disease are lacking. We aimed to assess the safety of metformin in patients with type 2 diabetes and advanced (approximately stage 5) chronic kidney disease.

METHODS

We did a retrospective, observational, cohort study of patients with type 2 diabetes who were enrolled prospectively in Taiwan's national health insurance research database between Jan 1, 2000, and June 30, 2009, and had follow-up data until Dec 31, 2009. We included individuals with a serum creatinine concentration greater than 530 μmol/L, which is approximately equivalent to stage 5 chronic kidney disease. From a consecutive sample of 12 350 patients with type 2 diabetes and chronic kidney disease, 1005 used metformin and 11 345 were non-users. We matched users and non-users of metformin by propensity score in a 1:3 ratio. Our primary outcome was all-cause mortality.

FINDINGS

813 metformin users were matched by propensity score to 2439 non-users. The two groups of patients did not differ significantly by 30 baseline clinical and socioeconomic variables. Median follow-up in the matched cohort was 2·1 years (range 0·3-9·8). All-cause mortality was reported in 434 (53%) of 813 metformin users and in 1012 (41%) of 2439 non-users. After multivariate adjustment, metformin use was an independent risk factor for mortality (adjusted hazard ratio 1·35, 95% CI 1·20-1·51; p<0·0001). The increased mortality risk was dose-dependent and was consistent across all subgroup analyses. However, metformin use compared with no use was associated with a higher but non-significant risk of metabolic acidosis (1·6 vs 1·3 events per 100 patient-years; adjusted hazard ratio 1·30, 95% CI 0·88-1·93; p=0·19).

INTERPRETATION

Use of metformin in people with type 2 diabetes and a serum creatinine concentration greater than 530 μmol/L is associated with a significantly increased risk of all-cause mortality compared with non-users. Metformin use should not be encouraged in this patient group.

FUNDING

Taipei Tzu Chi Hospital, Taipei Veterans General Hospital, Foundation for Poison Control, National Health Research Institutes, Ministry of Science and Technology of Taiwan.

Early glycaemic control among patients with type 2 diabetes and initial glucose-lowering treatment: a 13-year population-based cohort study

AIM

To examine real-life time trends in early glycaemic control in patients with type 2 diabetes between 2000 and 2012.

METHODS

We used population-based medical databases to ascertain the association between achievement of glycaemic control with initial glucose-lowering treatment in patients with incident type 2 diabetes in Northern Denmark. Success in reaching glycated haemoglobin (HbA1c) goals within 3-6 months was examined using regression analysis.

RESULTS

Of 38 418 patients, 91% started with oral glucose-lowering drugs in monotherapy. Metformin initiation increased from 32% in 2000-2003 to 90% of all patients in 2010-2012. Pretreatment (interquartile range) HbA1c levels decreased from 8.9 (7.6-10.7)% in 2000-2003 to 7.0 (6.5-8.1)% in 2010-2012. More patients achieved an HbA1c target of <7% (<53 mmol/mol) in 2010-2012 than in 2000-2003 [80 vs 60%, adjusted relative risk (aRR) 1.10, 95% confidence interval (CI) 1.08-1.13], and more achieved an HbA1c target of <6.5% [(<48 mmol/mol) 53 vs 37%, aRR 1.07 95% CI 1.03-1.11)], with similar success rates observed among patients aged <65 years without comorbidities. Achieved HbA1c levels were similar for different initiation therapies, with reductions of 0.8% (from 7.3 to 6.5%) on metformin, 1.5% (from 8.1 to 6.6%) on sulphonylurea, 4.0% (from 10.4 to 6.4%) on non-insulin combination therapies, and 3.8% (from 10.3 to 6.5%) on insulin monotherapy.

CONCLUSIONS

Pretreatment HbA1c levels in patients with incident type 2 diabetes have decreased substantially, which is probably related to earlier detection and treatment in accordance with changing guidelines. Achievement of glycaemic control has improved, but 20% of patients still do not attain an HbA1c level of <7% within the first 6 months of initial treatment.

Impact of ethnicity on progress of glycaemic control in 131,935 newly diagnosed patients with type 2 diabetes: a nationwide observational study from the Swedish National Diabetes Register

OBJECTIVES

Studies on ethnic disparities in glycaemic control have been contradictory, and compromised by excessively broad categories of ethnicity and inadequate adjustment for socioeconomic differences. We aimed to study the effect of ethnicity on glycaemic control in a large cohort of patients with type 2 diabetes.

SETTING

We used nationwide data (mainly from primary care) from the Swedish National Diabetes Register (2002-2011) to identify patients with newly diagnosed (within 12 months) type 2 diabetes.

PARTICIPANTS

We included 131,935 patients (with 713,495 appointments), representing 10 ethnic groups, who were followed up to 10 years.

PRIMARY AND SECONDARY OUTCOME MEASURES

Progress of glycated haemoglobin (HbA1c) for up to 10 years was examined. Mixed models were used to correlate ethnicity with HbA1c (mmol/mol). The effect of glycaemic disparities was examined by assessing the risk of developing albuminuria. The impact of ethnicity was compared to that of income, education and physical activity.

RESULTS

Immigrants, particularly those of non-Western origin, received glucose-lowering therapy earlier, had 30% more appointments but displayed poorer glycaemic control (2-5 mmol/mol higher HbA1c than native Swedes). Probability of therapy failure was 28-111% higher for non-Western groups than for native Swedes. High-income Western groups remained below the target-level of HbA1c for 4-5 years, whereas non-Western populations never reached the target level. These disparities translated into 51-92% higher risk of developing albuminuria. The impact of ethnicity was greater than the effect of income and education, and equal to the effect of physical activity.

CONCLUSIONS

Despite earlier pharmacological treatment and more frequent appointments, immigrants of non-Western origin display poorer glycaemic control and this is mirrored in a higher risk of developing albuminuria.

Metformin and metabolic diseases: a focus on hepatic aspects

Metformin has been widely used as a first-line anti-diabetic medicine for the treatment of type 2 diabetes (T2D). As a drug that primarily targets the liver, metformin suppresses hepatic glucose production (HGP), serving as the main mechanism by which metformin improves hyperglycemia of T2D. Biochemically, metformin suppresses gluconeogenesis and stimulates glycolysis. Metformin also inhibits glycogenolysis, which is a pathway that critically contributes to elevated HGP. While generating beneficial effects on hyperglycemia, metformin also improves insulin resistance and corrects dyslipidemia in patients with T2D. These beneficial effects of metformin implicate a role for metformin in managing non-alcoholic fatty liver disease. As supported by the results from both human and animal studies, metformin improves hepatic steatosis and suppresses liver inflammation. Mechanistically, the beneficial effects of metformin on hepatic aspects are mediated through both adenosine monophosphate-activated protein kinase (AMPK)-dependent and AMPK-independent pathways. In addition, metformin is generally safe and may also benefit patients with other chronic liver diseases.

Metformin utilisation in Australian community and aged care settings

OBJECTIVE

The objective of this study was to: (i) evaluate the potentially inappropriate prescribing (PIP; defined as the use of metformin in the presence of contraindications and/or use in excessive dosage based on the renal function) of metformin in people receiving medication reviews in Australia and (ii) identify the predictors for PIP of metformin.

METHOD

Retrospective study of patients taking metformin through a large medication review database, containing records between January 2010 and June 2012. Data, including demographics, medical conditions, medications and relevant pathology results, were extracted for analysis. Multivariate logistic regression analysis was used to detect risk factors for PIP of metformin.

RESULTS

Medication reviews pertaining to 6386 patients who received Home Medicines Reviews (HMRs, n=5327) or Residential Medication Management Reviews (RMMRs, n=1059) were included in this study. Overall, there were 12.9% (n=685) of patients in the HMR group and 17.4% (n=184) of patients in the RMMR group who had PIP of metformin. Multivariate logistic regression showed age, gender and type of medication review service as the significant (p<0.05) independent risk factors for PIP of metformin.

CONCLUSION

Metformin was often used in patients with contraindications, or in higher than recommended dosages in patients with renal impairment. Given the recent debate in the literature about the role of metformin in the presence of contraindications, a detailed prospective study in patients with contraindications and its association with lactic acidosis is warranted to establish the way in which metformin is to be used in these patients.

Saxagliptin and cardiovascular outcomes in patients with type 2 diabetes and moderate or severe renal impairment: observations from the SAVOR-TIMI 53 Trial

OBJECTIVE

The glycemic management of patients with type 2 diabetes mellitus (T2DM) and renal impairment is challenging, with few treatment options. We investigated the effect of saxagliptin in the Saxagliptin Assessment of Vascular Outcomes Recorded in Patients with Diabetes Mellitus (SAVOR)-Thrombolysis in Myocardial Infarction (TIMI) 53 trial according to baseline renal function.

RESEARCH DESIGN AND METHODS

Patients with T2DM at risk for cardiovascular events were stratified as having normal or mildly impaired renal function (estimated glomerular filtration rate [eGFR] >50 mL/min/1.73 m(2); n = 13,916), moderate renal impairment (eGFR 30-50 mL/min/1.73 m(2); n = 2,240), or severe renal impairment (eGFR <30 mL/min/1.73 m(2); n = 336) and randomized to receive saxagliptin or placebo. The primary end point was cardiovascular death, myocardial infarction, or ischemic stroke.

RESULTS

After a median duration of 2 years, saxagliptin neither increased nor decreased the risk of the primary and secondary composite end points compared with placebo, irrespective of renal function (all P for interactions ≥ 0.19). Overall, the risk of hospitalization for heart failure among the three eGFR groups of patients was 2.2% (referent), 7.4% (adjusted hazard ratio [HR] 2.38 [95% CI 1.95-2.91], P < 0.001), and 13.0% (adjusted HR 4.59 [95% CI 3.28-6.28], P < 0.001), respectively. The relative risk of hospitalization for heart failure with saxagliptin was similar (P for interaction = 0.43) in patients with eGFR >50 mL/min/1.73 m(2) (HR 1.23 [95% CI 0.99-1.55]), eGFR 30-50 mL/min/1.73 m(2) (HR 1.46 [95% CI 1.07-2.00]), and in patients with eGFR <30 (HR 0.94 [95% CI 0.52-1.71]). Patients with renal impairment achieved reductions in microalbuminuria with saxagliptin (P = 0.041) that were similar to those of the overall trial population.

CONCLUSIONS

Saxagliptin did not affect the risk of ischemic cardiovascular events, increased the risk of heart failure hospitalization, and reduced progressive albuminuria, irrespective of baseline renal function.

Durability of oral hypoglycemic agents in drug naïve patients with type 2 diabetes: report from the Swedish National Diabetes Register (NDR)

OBJECTIVE

To analyze the durability of monotherapy with different classes of oral hypoglycemic agents (OHAs) in drug naïve patients with type 2 diabetes mellitus (T2DM) in real life.

METHODS

Men and women with T2DM, who were new users of OHA monotherapy and registered in the Swedish National Diabetes Register July 2005-December 2011, were available (n=17 309) and followed for up to 5.5 years. Time to monotherapy failure, defined as discontinuation of continuous use with the initial agent, switch to a new agent, or add-on treatment of a second agent, was analyzed as a measure of durability. Baseline characteristics were balanced by propensity score matching 1:5 between groups of sulfonylurea (SU) versus metformin (n=4303) and meglitinide versus metformin (n=1308). HRs with 95% CIs were calculated using Cox regression models.

RESULTS

SU and meglitinide, as compared with metformin, were associated with increased risk of monotherapy failure (HR 1.74; 95% CI 1.56 to 1.94 and 1.66; 1.37 to 2.00 for SU and meglitinide, respectively). When broken down by type of monotherapy failure, SU and meglitinide were associated with an increased risk of add-on treatment of a second agent (HR 3.14; 95% CI 2.66 to 3.69 and 2.52; 1.89 to 3.37 for SU and meglitinide, respectively) and of switch to a new agent (HR 2.81; 95% CI 2.01 to 3.92 and 3.78; 2.25 to 6.32 for SU and meglitinide, respectively). The risk of discontinuation did not differ significantly between the groups.

CONCLUSIONS

In this nationwide observational study reflecting clinical practice, SU and meglitinide showed substantially increased risk of switch to a new agent or add on of a second agent compared with metformin. These results indicate superior glycemic durability with metformin compared with SU and also meglitinide in real life.

Metformin in patients with type 2 diabetes and kidney disease: a systematic review

IMPORTANCE

Metformin is widely viewed as the best initial pharmacological option to lower glucose concentrations in patients with type 2 diabetes mellitus. However, the drug is contraindicated in many individuals with impaired kidney function because of concerns of lactic acidosis.

OBJECTIVE

To assess the risk of lactic acidosis associated with metformin use in individuals with impaired kidney function.

EVIDENCE ACQUISITION

In July 2014, we searched the MEDLINE and Cochrane databases for English-language articles pertaining to metformin, kidney disease, and lactic acidosis in humans between 1950 and June 2014. We excluded reviews, letters, editorials, case reports, small case series, and manuscripts that did not directly pertain to the topic area or that met other exclusion criteria. Of an original 818 articles, 65 were included in this review, including pharmacokinetic/metabolic studies, large case series, retrospective studies, meta-analyses, and a clinical trial.

RESULTS

Although metformin is renally cleared, drug levels generally remain within the therapeutic range and lactate concentrations are not substantially increased when used in patients with mild to moderate chronic kidney disease (estimated glomerular filtration rates, 30-60 mL/min per 1.73 m2). The overall incidence of lactic acidosis in metformin users varies across studies from approximately 3 per 100,000 person-years to 10 per 100,000 person-years and is generally indistinguishable from the background rate in the overall population with diabetes. Data suggesting an increased risk of lactic acidosis in metformin-treated patients with chronic kidney disease are limited, and no randomized controlled trials have been conducted to test the safety of metformin in patients with significantly impaired kidney function. Population-based studies demonstrate that metformin may be prescribed counter to prevailing guidelines suggesting a renal risk in up to 1 in 4 patients with type 2 diabetes mellitus--use which, in most reports, has not been associated with increased rates of lactic acidosis. Observational studies suggest a potential benefit from metformin on macrovascular outcomes, even in patients with prevalent renal contraindications for its use.

CONCLUSIONS AND RELEVANCE

Available evidence supports cautious expansion of metformin use in patients with mild to moderate chronic kidney disease, as defined by estimated glomerular filtration rate, with appropriate dosage reductions and careful follow-up of kidney function.

Lifestyle factors associated with type 2 diabetes and use of different glucose-lowering drugs: cross-sectional study

Aims

To examine the lifestyle profile among persons with and without Type 2 diabetes mellitus (DM) and among users of different glucose-lowering drugs.

Methods

We used questionnaire data from a Danish health survey and identified presence of Type 2 DM and use of medications through medical databases. We calculated age- and gender-standardized prevalence ratios (PRs) of lifestyle factors according to Type 2 DM and different glucose-lowering drugs.

Results

Of 21,637 survey participants aged 25–79 years, 680 (3%) had Type 2 DM (median age 63 years) with a median diabetes duration of 5 years. Participants with Type 2 DM had a substantially higher prevalence of obesity (36% vs. 13%, PR: 3.1, 95% confidence interval (CI): 2.8–3.6), yet more reported to eat a very healthy diet (25% vs. 21%, PR: 1.2, 95% CI: 1.0–1.4) and to exercise regularly (67% vs. 53%, PR: 1.3, 95% CI: 1.2–1.4). Also, fewer were current smokers or had high alcohol intake. When compared with metformin users, obesity was substantially less prevalent in users of sulfonylurea (PR: 0.5, 95% CI: 0.4–0-8), and insulin and analogues (PR: 0.4, 95% CI: 0.3–0.7). Tobacco smoking was more prevalent in sulfonylurea users (PR: 1.4, 95% CI: 0.9–2.1) compared with metformin users. We found no material differences in physical exercise, diet or alcohol intake according to type of glucose-lowering drug.

Conclusions

Type 2 DM patients are substantially more obese than other individuals, but otherwise report to have a healthier lifestyle. Metformin use is strongly associated with obesity, whereas sulfonylurea use tends to be associated with tobacco smoking.

Improving postapproval drug safety surveillance: getting better information sooner

Adverse drug events (ADEs) are an important public health concern, accounting for 5% of all hospital admissions and two-thirds of all complications occurring shortly after hospital discharge. There are often long delays between when a drug is approved and when serious ADEs are identified. Recent and ongoing advances in drug safety surveillance include the establishment of government-sponsored networks of population databases, the use of data mining approaches, and the formal integration of diverse sources of drug safety information. These advances promise to reduce delays in identifying drug-related risks and in providing reassurance about the absence of such risks.

Chronic kidney disease in type 2 diabetes: lessons from the Renal Insufficiency And Cardiovascular Events (RIACE) Italian Multicentre Study

The Renal Insufficiency And Cardiovascular Events (RIACE) Italian Multicentre Study is an ongoing observational survey that examines the role of estimated glomerular filtration rate (eGFR) as an independent predictor of cardiovascular and renal outcomes in 15,773 Italian subjects with type 2 diabetes. The analysis of data collected at the enrollment visit provided a picture of chronic kidney disease (CKD) and its association with other complications, risk factors for cardiovascular disease (CVD) and treatments in a large contemporary cohort. Main results of this analysis were that (a) non-albuminuric renal impairment is the predominant clinical phenotype in patients, particularly women, with reduced eGFR; (b) concordance between CKD and diabetic retinopathy is low, with only a minority of patients with renal dysfunction presenting with any or advanced retinal lesions; (c) the non-albuminuric form is associated with a significant prevalence of CVD, especially at the level of the coronary vascular bed; (d) CKD is associated with hemoglobin (Hb) A1c variability more than with average HbA1c, whereas retinopathy and CVD are not; (e) in elderly individuals with moderate-to-severe eGFR reduction, use of agents which are not recommended, such as sulphonylureas and metformin, is still frequent; and (f) though complications are generally more prevalent in men (except non-albuminuric renal impairment) women show a less favorable CVD risk profile and achieve therapeutic targets to a lesser extent than men, despite the fact that treatment intensity is not lower. These data update existing information on the natural history of CKD in patients with type 2 diabetes.

Medication pitfalls in the CKD clinic: case presentations

The kidney plays a major role in pharmacokinetics and pharmacodynamics of drugs; therefore, medication errors can result from failure to properly adjust medications in patients with CKD. It is the responsibility of all health-care providers to work collectively when reviewing medications, initiating new medications, and adjusting doses of current medications. Awareness of appropriate dosing recommendations can significantly decrease medication error-associated morbidity, mortality, and cost.

How are patients with type 2 diabetes and renal disease monitored and managed? Insights from the observational OREDIA study

Background and aim

Chronic kidney disease (CKD) is frequent in type 2 diabetes mellitus (T2DM), and therapeutic management of diabetes is more challenging in patients with renal impairment (RI). The place of metformin is of particular interest since most scientific societies now recommend using half the dosage in moderate RI and abstaining from use in severe RI, while the classic contraindication with RI has not been removed from the label. This study aimed to assess the therapeutic management, in particular the use of metformin, of T2DM patients with CKD in real life.

Methods

This was a French cross-sectional observational study: 3,704 patients with T2DM diagnosed for over 1 year and pharmacologically treated were recruited in two cohorts (two-thirds were considered to have renal disease [CKD patients] and one-third were not [non-CKD patients]) by 968 physicians (81% general practitioners) in 2012.

Results

CKD versus non-CKD patients were significantly older with longer diabetes history, more diabetic complications, and less strict glycemic control (mean glycated hemoglobin [HbA_1c] 7.5% versus 7.1%; 25% of CKD patients had HbA_1c ≥8% versus 15% of non-CKD patients). Fifteen percent of CKD patients had severe RI, and 66% moderate RI. Therapeutic management of T2DM was clearly distinct in CKD, with less use of metformin (62% versus 86%) but at similar mean daily doses (~2 g/d). Of patients with severe RI, 33% were still treated with metformin, at similar doses. For other oral anti-diabetics, a distinct pattern of use was seen across renal function (RF): use of sulfonylureas (32%, 31%, and 20% in normal RF, moderate RI, and severe RI, respectively) and DPP4-i (dipeptidyl peptidase-4 inhibitors) (41%, 36%, and 25%, respectively) decreased with RF, while that of glinides increased (8%, 14%, and 18%, respectively). CKD patients were more frequently treated with insulin (40% versus 16% of non-CKD patients), and use of insulin increased with deterioration of RF (19%, 39%, and 61% of patients with normal RF, moderate RI, and severe RI, respectively). Treatment was modified at the end of the study-visit in 34% of CKD patients, primarily to stop or reduce metformin. However, metformin was stopped in only 40% of the severe RI patients.

Conclusion

Despite a fairly good detection of CKD in patients with T2DM, RI was insufficiently taken into account for adjusting anti-diabetic treatment.

Medication safety and chronic kidney disease in older adults prescribed metformin: a cross-sectional analysis

Background

Medication safety in patients with chronic kidney disease (CKD) is a growing concern. This is particularly relevant in older adults due to underlying CKD. Metformin use is contraindicated in patients with abnormal kidney function; however, many patients are potentially prescribed metformin inappropriately. We evaluated the prevalence of CKD among older adults prescribed metformin for type 2 diabetes mellitus using available equations to estimate kidney function and examined demographic characteristics of patients who were potentially inappropriately prescribed metformin.

Methods

We conducted a cross-sectional analysis of older adults aged ≥65 years prescribed metformin from March 2008-March 2009 at an urban tertiary-care facility in Seattle, Washington, USA. CKD was defined using National Kidney Foundation-Kidney Disease Outcomes Quality Initiative criteria. Creatinine clearance was calculated using the Cockcroft-Gault equation; estimated glomerular filtration rate was calculated using the abbreviated Modification of Diet in Renal Disease (MDRD) and CKD-Epidemiology (EPI) Collaboration equations. Regression analyses were used to determine the associations between demographic characteristics and prevalent CKD.

Results

Among 356 subjects (median age 69 years, 52.5% female, 39.4% non-Hispanic black), prevalence of stage 3 or greater CKD calculated by any of the equations was 31.4%. The Cockcroft-Gault equation identified more subjects as having CKD (23.7%) than the abbreviated MDRD (21.1%) or CKD-EPI (21.7%) equations (P < 0.001). Older age (OR = 1.13, 95% CI 1.08-1.19) and female sex (OR = 2.51, 95% CI 1.44-4.38) were associated with increased odds of potentially inappropriate metformin prescription due to CKD; non-Hispanic black race was associated with decreased odds of potentially inappropriate metformin prescription due to CKD (OR = 0.41, 95% CI 0.23-0.71).

Conclusions

CKD is common in older adults prescribed metformin for type 2 diabetes, raising concern for potentially inappropriate medication use. No single equation to estimate kidney function may accurately identify CKD in this population. Medication safety deserves greater consideration among elderly patients due to the widespread prevalence of CKD.

Use of metformin in diseases of aging

Metformin is the most commonly prescribed medication for type 2 diabetes (T2DM) in the world. It has primacy in the treatment of this disease because of its safety record and also because of evidence for reduction in the risk of cardiovascular events. Evidence has accumulated indicating that metformin is safe in people with stage 3 chronic kidney disease (CKD-3). It is estimated that roughly one-quarter of people with CKD-3 and T2DM in the United States (well over 1 million) are ineligible for metformin treatment because of elevated serum creatinine levels. This could be overcome if a scheme, perhaps based on pharmacokinetic studies, could be developed to prescribe reduced doses of metformin in these individuals. There is also substantial evidence from epidemiologic studies to indicate that metformin may not only be safe, but may actually benefit people with heart failure (HF). Prospective, randomized trials of the use of metformin in HF are needed to investigate this possibility.

Metformin and other antidiabetic agents in renal failure patients

This review mainly focuses on metformin, and considers oral antidiabetic therapy in kidney transplant patients and the potential benefits and risks of antidiabetic agents other than metformin in patients with chronic kidney disease (CKD). In view of the debate concerning lactic acidosis associated with metformin, this review tries to solve a paradox: metformin should be prescribed more widely because of its beneficial effects, but also less widely because of the increasing prevalence of contraindications to metformin, such as reduced renal function. Lactic acidosis appears either as part of a number of clinical syndromes (i.e., unrelated to metformin), induced by metformin (involving an analysis of the drug's pharmacokinetics and mechanisms of action), or associated with metformin (a more complex situation, as lactic acidosis in a metformin-treated patient is not necessarily accompanied by metformin accumulation, nor does metformin accumulation necessarily lead to lactic acidosis). A critical analysis of guidelines and literature data on metformin therapy in patients with CKD is presented. Following the present focus on metformin, new paradoxical issues can be drawn up, in particular: (i) metformin is rarely the sole cause of lactic acidosis; (ii) lactic acidosis in patients receiving metformin therapy is erroneously still considered a single medical entity, as several different scenarios can be defined, with contrasting prognoses. The prognosis for severe lactic acidosis seems even better in metformin-treated patients than in non-metformin users.

Metformin in peritoneal dialysis: a pilot experience

OBJECTIVE

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.

METHODS

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.

RESULTS

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).

CONCLUSIONS

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.

Genetic architecture of human fibrotic diseases: disease risk and disease progression

Genetic studies of human diseases have identified multiple genetic risk loci for various fibrotic diseases. This has provided insights into the myriad of biological pathways potentially involved in disease pathogenesis. These discoveries suggest that alterations in immune responses, barrier function, metabolism and telomerase activity may be implicated in the genetic risks for fibrotic diseases. In addition to genetic disease-risks, the identification of genetic disease-modifiers associated with disease complications, severity or prognosis provides crucial insights into the biological processes implicated in disease progression. Understanding the biological processes driving disease progression may be critical to delineate more effective strategies for therapeutic interventions. This review provides an overview of current knowledge and gaps regarding genetic disease-risks and genetic disease-modifiers in human fibrotic diseases.

Unleash metformin: reconsideration of the contraindication in patients with renal impairment

OBJECTIVE

To evaluate the expanded use of metformin in renal impairment.

DATA SOURCES

The MEDLINE database via PubMed, Web of Science, and Cumulative Index to Nursing and Allied Health were searched in August 2013 and included studies from 1950 onward.

STUDY SELECTION AND DATA EXTRACTION

The search included comparative trials, observational cohort studies, and meta-analyses using the terms diabetes mellitus, metformin, renal insufficiency, and acidosis, lactic.

DATA SYNTHESIS

One randomized controlled trial, 1 meta-analysis, 1 case-control, and 3 prospective-cohort studies, representing about 150 000 patients, revealed that metformin is safe in patients with stable mild-moderate renal impairment. The incidence of lactic acidosis is low and similar to sulfonylureas. In addition, reduced risks of cardiovascular disease, all-cause mortality, or any acidosis/serious infection were seen with metformin use in mild-to-moderate renal impairment.

CONCLUSIONS

Data over the past decade refute the historical contraindication in patients with renal impairment and suggest that the risk of metformin-associated lactic acidosis is low in stable mild-to-moderate renal impairment and similar to the risk with other type 2 diabetes mellitus (DM2) medications with no renal impairment restrictions. Because of its unique impact on microvascular and macrovascular complications, it is advantageous to utilize metformin as the cornerstone in DM2 treatment for as long as possible, including in those patients with mild to moderate stages of renal impairment with no additional contraindications. A dosage reduction is recommended if estimated glomerular filtration rate (eGFR) is between 30 and 45 mL/min/1.73 m(2) and discontinuation if eGFR is <30 mL/min/1.73 m(2).

Towards renewed health economic simulation of type 2 diabetes: risk equations for first and second cardiovascular events from Swedish register data

OBJECTIVE

Predicting the risk of future events is an essential part of health economic simulation models. In pursuit of this goal, the current study aims to predict the risk of developing first and second acute myocardial infarction, heart failure, non-acute ischaemic heart disease, and stroke after diagnosis in patients with type 2 diabetes, using data from the Swedish National Diabetes Register.

MATERIAL AND METHODS

Register data on 29,034 patients with type 2 diabetes were analysed over five years of follow up (baseline 2003). To develop and validate the risk equations, the sample was randomly divided into training (75%) and test (25%) subsamples. The Weibull proportional hazard model was used to estimate the coefficients of the risk equations, and these were validated in both the training and the test samples.

RESULTS

In total, 4,547 first and 2,418 second events were observed during the five years of follow up. Experiencing a first event substantially elevated the risk of subsequent events. There were heterogeneities in the effects of covariates within as well as between events; for example, while for females the hazard ratio of having a first acute myocardial infarction was 0.79 (0.70-0.90), the hazard ratio of a second was 1.21 (0.98-1.48). The hazards of second events decreased as the time since first events elapsed. The equations showed adequate calibration and discrimination (C statistics range: 0.70-0.84 in test samples).

CONCLUSION

The accuracy of health economic simulation models of type 2 diabetes can be improved by ensuring that they account for the heterogeneous effects of covariates on the risk of first and second cardiovascular events. Thus it is important to extend such models by including risk equations for second cardiovascular events.