Prescribing metformin in type 2 diabetes with a contraindication: prevalence and outcome

Sex differences in type 2 diabetes

The prevalence of type 2 diabetes mellitus is increasing in both sexes, but men are usually diagnosed at a younger age and lower body fat mass than women. Worldwide, an estimated 17.7 million more men than women have diabetes mellitus. Women appear to bear a greater risk factor burden at the time of their type 2 diabetes diagnosis, especially obesity. Moreover, psychosocial stress might play a more prominent role in diabetes risk in women. Across their lifespan, women experience greater hormone fluctuations and body changes due to reproductive factors than men. Pregnancies can unmask pre-existing metabolic abnormalities, resulting in the diagnosis of gestational diabetes, which appears to be the most prominent risk factor for progression to type 2 diabetes in women. Additionally, menopause increases women's cardiometabolic risk profile. Due to the progressive rise in obesity, there is a global increase in women with pregestational type 2 diabetes, often with inadequate preconceptual care. There are differences between men and women regarding type 2 diabetes and other cardiovascular risk factors with respect to comorbidities, the manifestation of complications and the initiation of and adherence to therapy. Women with type 2 diabetes show greater relative risk of CVD and mortality than men. Moreover, young women with type 2 diabetes are currently less likely than men to receive the treatment and CVD risk reduction recommended by guidelines. Current medical recommendations do not provide information on sex-specific or gender-sensitive prevention strategies and management. Thus, more research on sex differences, including the underlying mechanisms, is necessary to increase the evidence in the future. Nonetheless, intensified efforts to screen for glucose metabolism disorders and other cardiovascular risk factors, as well as the early establishment of prophylactic measures and aggressive risk management strategies, are still required for both men and women at increased risk of type 2 diabetes. In this narrative review we aim to summarise sex-specific clinical features and differences between women and men with type 2 diabetes into risk factors, screening, diagnosis, complications and treatment.

Cerebrolysin Alleviating Effect on Glutamate-Mediated Neuroinflammation Via Glutamate Transporters and Oxidative Stress

Glutamate, one of the most important excitatory neurotransmitters, acts as a signal transducer in peripheral tissues and endocrine cells. Excessive glutamate secretion has been shown to cause excitotoxicity and neurodegenerative disease. Cerebrolysin is a mixture of enzymatically treated peptides derived from pig brain including neurotrophic factors, like brain-derived neurotrophic factor (BDNF), glial cell line-derived neurotrophic factor (GDNF), nerve growth factor (NGF), and ciliary neurotrophic factor (CNTF). The present study investigated the protective effects of cerebrolysin on glutamate transporters (EAAT 1, EAAT 2) and cytokines (IL-1β and IL-10) activity in glutamate-mediated neurotoxicity. Primary cortex neuron culture was exposed to glutamate and successively treated with various cerebrolysin concentrations for 24 and 48 h. Our data showed that cerebrolysin primarily protects neurons by decreasing glutamate concentration in the synaptic cleft. In addition, Cerebrolysin can decrease oxidative stress and neuron cell damage by increasing antioxidant activity and decreasing inflammation cytokine levels.

Metformin and cognition from the perspectives of sex, age, and disease

Metformin is the safest and the most widely prescribed first-line therapy for managing hyperglycemia due to different underlying causes, primarily type 2 diabetes mellitus. In addition to its euglycemic properties, metformin has stimulated a wave of clinical trials to investigate benefits on aging-related diseases and longevity. Such an impact on the lifespan extension would undoubtedly expand the therapeutic utility of metformin regardless of glycemic status. However, there is a scarcity of studies evaluating whether metformin has differential cognitive effects across age, sex, glycemic status, metformin dose, and duration of metformin treatment and associated pathological conditions. By scrutinizing the available literature on animal and human studies for metformin and brain function, we expect to shed light on the potential impact of metformin on cognition across age, sex, and pathological conditions. This review aims to provide readers with a broader insight of (a) how metformin differentially affects cognition and (b) why there is a need for more translational and clinical studies examining multifactorial interactions. The outcomes of such comprehensive studies will streamline precision medicine practices, avoiding "fit for all" approach, and optimizing metformin use for longevity benefit irrespective of hyperglycemia.

Dose adjustment of metformin and dipeptidyl-peptidase IV inhibitors in diabetic patients with renal dysfunction

OBJECTIVES

This analysis of real-world data aimed to (a) determine the proportion of Type II diabetes (T2DM) patients treated with metformin or dipeptidyl peptidase-4 inhibitors (DPP-4i) that require dose adjustment or therapy discontinuation due to chronic kidney disease (CKD), and (b) to assess the time required to dose adjustment from the time of worsening of CKD.

METHODS

In this retrospective study, two study populations were defined in a large healthcare organization. In the cross-sectional analysis, the distribution of CKD stages and the appropriate dosage of metformin and DPP-4i in 2013 was examined according to renal function among T2DM patients. In the longitudinal analysis, a cohort was defined to assess the time elapsed from first indication worsening of CKD to dose adjustment, among patients treated with those medications during years 2006-2013.

RESULTS

Among patients treated with metformin or DPP-4i, one third of patients with CKD failed to adjust the dosage or to discontinue metformin or DPP-4i as indicated. Median time for dose adjustment or discontinuation was significantly longer for DPP-4i than for metformin (9.8 compared to 16.8 months for metformin and DPP-4i, respectively; p-value <.001).

CONCLUSIONS

This real-world data analysis showed that adjustment of dose or discontinuation of metformin or DPP-4i in patients with worsening CKD occurred less often in DPP-4i users than metformin users and took a longer time.

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.

Patterns of glycaemic control in patients with type 2 diabetes mellitus initiating second-line therapy after metformin monotherapy: Retrospective data for 10 256 individuals from the United Kingdom and Germany

AIM

To investigate determinants of change in glycated haemoglobin (HbA1c) in patients with type 2 diabetes mellitus (T2DM) at 6 months after initiating uninterrupted second-line glucose-lowering therapies.

MATERIALS AND METHODS

This cohort study utilized retrospective data from 10 256 patients with T2DM who initiated second-line glucose-lowering therapy (switch from or add-on to metformin) between 2011 and 2014 in Germany and the UK. Effects of pre-specified patient characteristics on 6-month HbA1c changes were assessed using analysis of covariance.

RESULTS

Patients had a mean (standard error [SE]) baseline HbA1c of 8.68% (0.02); 28.5% of patients discontinued metformin and switched to an alternative therapy and the remainder initiated add-on therapy. Mean (SE) unadjusted 6-month HbA1c change was -1.27% (0.02). When adjusted for baseline HbA1c, 6-month changes depended markedly on the magnitude of the baseline HbA1c (HbA1c <9%, -0.45% per unit increase in HbA1c; HbA1c ≥9%, -0.87% per unit increase in HbA1c). Adjusted mean 6-month HbA1c reductions showed slight treatment differences (range, 0.92-1.09%; P < .001). Greater reductions in HbA1c were associated with second-line treatment initiation within 6 months of T2DM diagnosis (1.36% vs 1.03% [P < .001]) and advanced age (≥70 years, 1.13%; <70 years, 1.02% [P < .001]).

CONCLUSIONS

Many patients with T2DM have very high HbA1c levels when initiating second-line therapy, indicating the need for earlier treatment intensification. Patient-specific factors merit consideration when making treatment decisions.

A 24-week study to evaluate the efficacy and safety of once-weekly dulaglutide added on to glimepiride in type 2 diabetes (AWARD-8)

AIMS

To evaluate the safety and efficacy of once-weekly dulaglutide 1.5 mg, a long-acting glucagon-like peptide-1 receptor agonist, compared with placebo in patients with type 2 diabetes (T2D) on glimepiride monotherapy.

METHODS

This phase III, randomized (4 : 1; dulaglutide:placebo), double-blind, placebo-controlled, 24-week study compared the safety and efficacy of once-weekly dulaglutide 1.5 mg with placebo in sulphonylurea-treated (≥half-maximal dose, stable ≥3 months) patients (N = 300) with T2D and inadequate glycaemic control [glycated haemoglobin (HbA1c) ≥7.5 and ≤9.5% (≥58 mmol/mol and ≤80 mmol/mol)]. Analysis was carried out according to intention-to-treat.

RESULTS

At baseline, the mean participant age was 58 years; mean HbA1c was 8.4% (68 mmol/mol) and mean weight was 85.5 kg. Dulaglutide 1.5 mg was superior to placebo at 24 weeks for HbA1c reduction from baseline with a between-group HbA1c difference of -1.3% [95% confidence interval (CI) -1.6, -1.0] or -14 mmol/mol (95% CI -17, -11); p < 0.001. A greater proportion of participants in the dulaglutide group reached an HbA1c level of <7.0% (53 mmol/mol) compared with placebo (55.3% vs 18.9%; p < 0.001). Dulaglutide significantly decreased fasting serum glucose from baseline compared with placebo (between-group difference -1.86 mmol/l (95% CI -2.58, -1.14) or -33.54 mg/dl (95% CI -46.55, -20.53); p < 0.001. Weight was decreased significantly from baseline in the dulaglutide group (p < 0.001); the between-group difference was not significant. The most common treatment-emergent adverse events for dulaglutide 1.5 mg were gastrointestinal: nausea (10.5%), diarrhoea (8.4%) and eructation (5.9%). Total hypoglycaemia was higher with dulaglutide 1.5 mg vs placebo (2.37 and 0.07 events/participant/year, respectively; p = 0.025). No severe hypoglycaemia was reported.

CONCLUSIONS

Once-weekly dulaglutide 1.5 mg had a favourable benefit/risk profile when added to glimepiride monotherapy.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Alogliptin + metformin combination for the treatment of type 2 diabetes mellitus

The impact of type 2 diabetes mellitus continues to grow worldwide, with appropriate glycemic management being a cornerstone of treatment to minimize the risk of macrovascular and microvascular complications. While metformin is widely utilized as a first-line agent for patients without a contraindication to therapy, treatment guidelines recommend a variety of options for second-line dual therapy with patient-specific choices depending on assessment of hypoglycemia risk, weight effects, tolerability, cost and other considerations. Incretin-based therapies, inclusive of dipeptidyl peptidase-4 inhibitors, have become a widely utilized group of medications due to their potentially advantageous effects, such as a low risk of hypoglycemia and overall favorable tolerability profile. Accordingly, fixed-dose combination products containing metformin in combination with a dipeptidyl peptidase-4 inhibitor have been developed by several manufacturers. This article summarizes the current evidence for the safety and efficacy of alogliptin and metformin used in combination for the treatment of type 2 diabetes mellitus.

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.

Sex differences in type 2 diabetes: focus on disease course and outcomes

BACKGROUND

Women with type 2 diabetes (T2D) are less likely to reach the goals for hemoglobin A1c compared with men, and have higher all-cause mortality. The risk of cardiovascular disease is elevated among both men and women with T2D, however, the risk has declined among men over recent years while it remains stationary in women. Reasons for these sex differences remain unclear, and guidelines for diabetes treatment do not differentiate between sexes. Possible causes for varying outcome include differences in physiology, treatment response, and psychological factors. This review briefly outlines sex differences in hormonal pathophysiology, and thereafter summarizes the literature to date on sex differences in disease course and outcome.

METHODS

Systematic searches were performed on PubMed using "sex", "gender", and various glucose-lowering therapies as keywords. Earlier reviews are summarized and results from individual studies are reported. Reference lists from studies were used to augment the search.

RESULTS

There is an increased risk of missing the diagnosis of T2D when screening women with only fasting plasma glucose instead of with an oral glucose tolerance test. The impact of various risk factors for complications may differ by sex. Efficacy and side effects of some glucose-lowering drugs differ between men and women. Men with T2D appear to suffer more microvascular complications, while women have higher morbidity and mortality in cardiovascular disease and also fare worse psychologically.

CONCLUSION

Few studies to date have focused on sex differences in T2D. Several questions demand further study, such as whether risk factors and treatment guidelines should be sex-specific. There is a need for clinical trials designed specifically to evaluate sex differences in efficacy and outcome of the available treatments.

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).

Metformin revisited: a critical review of the benefit-risk balance in at-risk patients with type 2 diabetes

Metformin is unanimously considered a first-line glucose-lowering agent. Theoretically, however, it cannot be prescribed in a large proportion of patients with type 2 diabetes because of numerous contraindications that could lead to an increased risk of lactic acidosis. Various observational data from real-life have shown that many diabetic patients considered to be at risk still receive metformin and often without appropriate dose adjustment, yet apparently with no harm done and particularly no increased risk of lactic acidosis. More interestingly, recent data have suggested that type 2 diabetes patients considered at risk because of the presence of traditional contraindications may still derive benefit from metformin therapy with reductions in morbidity and mortality compared with other glucose-lowering agents, especially sulphonylureas. The present review analyzes the benefit-risk balance of metformin therapy in special populations, namely, patients with stable coronary artery disease, acute coronary syndrome or myocardial infarction, congestive heart failure, renal impairment or chronic kidney disease, hepatic dysfunction and chronic respiratory insufficiency, all conditions that could in theory increase the risk of lactic acidosis. Special attention is also paid to elderly patients with type 2 diabetes, a population that is growing rapidly, as older patients can accumulate several comorbidities classically considered contraindications to the use of metformin. A review of the recent scientific literature suggests that reassessment of the contraindications of metformin is now urgently needed to prevent physicians from prescribing the most popular glucose-lowering therapy in everyday clinical practice outside of the official recommendations.

Pharmacokinetic considerations for the treatment of diabetes in patients with chronic kidney disease

INTRODUCTION

People with chronic kidney disease (CKD) of stages 3 - 5 (creatinine clearance < 60 ml/min) represent ≈ 25% of patients with type 2 diabetes mellitus (T2DM), but the problem is underrecognized or neglected in clinical practice. However, most oral antidiabetic agents have limitations in case of renal impairment (RI), either because they require a dose adjustment or because they are contraindicated for safety reasons.

AREAS COVERED

The author performed an extensive literature search to analyze the influence of RI on the pharmacokinetics (PK) of glucose-lowering agents and the potential consequences for clinical practice.

EXPERT OPINION

As a result of PK interferences and for safety reasons, the daily dose should be reduced according to glomerular filtration rate (GFR) or even the drug is contraindicated in presence of severe CKD. This is the case for metformin (risk of lactic acidosis) and for many sulfonylureas (risk of hypoglycemia). At present, however, the exact GFR cutoff for metformin use is controversial. New antidiabetic agents are better tolerated in case of CKD, although clinical experience remains quite limited for most of them. The dose of DPP-4 inhibitors should be reduced (except for linagliptin), whereas both the efficacy and safety of SGLT2 inhibitors are questionable in presence of CKD.

Diabetes management in the kidney patient

Hyperglycemia management in chronic kidney disease (CKD) patients presents difficult challenges, partly due to the complexity involved in treating these patients, and partly due to lack of data supporting benefits of tight glycemic control. While hyperglycemia is central to the pathogenesis and management of diabetes, hypoglycemia and glucose variability also contribute to outcomes. Multiple agents with different mechanisms of action are now available; some can lower glucose levels without the risk of hypoglycemia. This article reviews metabolic changes present in kidney impairment/failure, current views about glycemic goals, and treatment options for the diabetic patient with CKD.

Proposal for the administration of metformin in patients with chronic kidney disease

Metformin is the first-line, widely used oral antidiabetic agent for the management of type 2 diabetes. There is increasing evidence that metformin use results in a reduction in cardiovascular morbidity and mortality, and might have anticancer activity. An extremely rare, but potentially life-threatening adverse effect of metformin is lactic acidosis, therefore, its use is traditionally contraindicated if the glomerular filtrate rate is below 60 mL/min. However, lactic acidosis is always associated with acute events, such as hypovolemia, acute cardiorespiratory illness, severe sepsis and acute renal or hepatic failure. Furthermore, administration of insulins and conventional antihyperglycemic agents increases the risk of severe hypoglycemic events when renal function is reduced. Therefore, the magnitude of the benefit of metformin use would outweigh potential risk of lactic acidosis in moderate chronic renal disease. After reviewing the literature, the authors give a proposal for the administration of metformin, according to the calculated glomerular filtrate rate. Orv.Hetil., 2012, 153, 1527–1535.

Inappropriate metformin prescribing in elderly type 2 diabetes mellitus (T2DM) patients

PURPOSE

Metformin is the most commonly prescribed anti-diabetic medication. However, it is often used despite the presence of contraindications and in unlicensed indications. The main aim of this study was to evaluate the frequency of metformin use before hospitalization in spite of contraindications in patients with type 2 diabetes mellitus (T2DM) and to evaluate the prevalence of metformin - associated side effects.

MATERIAL/METHODS

558 hospitalized patients (mean age = 66.65 ± 12.73 years) with poorly controlled T2DM were enrolled. Detailed medical history including the duration of T2DM, duration of hypoglycemic agents usage prior to hospitalization and possible metformin-associated side effects was recorded. Patients were subjected to a thorough physical examination and indispensable biochemical and diagnostic research panel was performed to establish the degree of heart failure, sufficiency of the respiratory system and kidney function.

RESULTS

335 out of 558 patients were treated before hospitalization with metformin alone or in combination with other hypoglycemic agents, mostly sulfonylureas. Contraindications to metformin were found in 275 patients and despite this 120 of them were using this medication in an average dose of 1793.91 ± 701.61 mg. However, none of them reported any serious adverse effects and no significant pH changes were observed. Only three patients reported moderate dyspepsia.

CONCLUSIONS

The results of this study indicate a relatively good tolerability of metformin by patients with the traditional contraindications to this drug. These findings support other authors' suggestion that indications and contraindications to metformin should be re-evaluated.

The assessment of renal function in relation to the use of drugs in elderly in nursing homes; a cohort study

Background

Renal function decreases with age. Dosage adjustment according to renal function is indicated for many drugs, in order to avoid adverse reactions of medications and/or aggravation of renal impairment. There are several ways to assess renal function in the elderly, but no way is ideal. The aim of the study was to explore renal function in elderly subjects in nursing homes and the use of pharmaceuticals that may be harmful to patients with renal impairment.

Methods

243 elderly subjects living in nursing homes were included. S-creatinine and s-cystatin c were analysed. Renal function was estimated using Cockcroft-Gault formula, Modification of Diet in Renal Disease (MDRD) and cystatin C-estimated glomerular filtration rate (GFR). Concomitant medication was registered and four groups of renal risk drugs were identified: metformin, nonsteroidal anti-inflammatory drugs (NSAID), angiotensin-converting enzyme -inhibitors/angiotensin receptor blockers and digoxin. Descriptive statistics and the Kappa test for concordance were used.

Results

Reduced renal function (cystatin C-estimated GFR < 60 ml/min) was seen in 53%. Normal s-creatinine was seen in 41% of those with renal impairment. Renal risk drugs were rather rarely prescribed, with exception for ACE-inhibitors. Poor concordance was seen between the GFR estimates as concluded by other studies.

Conclusions

The physician has to be observant on renal function when prescribing medications to the elderly patient and not only rely on s-creatinine level. GFR has to be estimated before prescribing renal risk drugs, but using different estimates may give divergence in the results.

Review: metformin: potential benefits and use in chronic kidney disease

Diabetes mellitus is the commonest cause of end-stage renal failure in both Australia and New Zealand. In addition, the burden of diabetes is prominent in those with chronic kidney disease who have not yet reached the requirement for renal replacement therapy. While diabetes is associated with a higher incidence of mortality and morbidity in all populations studied with kidney disease, little is known about optimal treatment strategies for hyperglycaemia and the effects of glycaemic treatment in this large group of patients. Metformin is recommended as the drug of first choice in patients diagnosed with type 2 diabetes in the USA, Europe and Australia. There are potential survival benefits associated with the use of metformin in additional to recent studies suggesting benefits in respect to cardiovascular outcomes and metabolic parameters. The use of metformin has been limited in patients with renal disease because of the perceived risk of lactic acidosis; however, it is likely that use of this drug would be beneficial in many with chronic kidney disease. Thus the potential benefits and harms of metformin are outlined in this review with suggestions for its clinical use in those with kidney disease.