Effects of body mass index or dosage on gastrointestinal disorders associated with extended-release metformin in type 2 diabetes: Sub-analysis of a Phase IV open-label trial in Chinese patients

Predictors of gastrointestinal complaints in patients on metformin therapy

Although being very effective in the treatment of diabetes and a few other conditions, metformin (MTF) cannot be tolerated by many patients due to gastrointestinal (GI) complaints. A number of risk factors for intolerance were identified, but many are still controversial or uninvestigated. The aim of this study was to further investigate possible risk factors for the occurrence of GI complaints in patients on MTF therapy. A cross-sectional design was used for this multicentric study on adult patients visiting 50 community pharmacies in Montenegro. The patients were surveyed by semi-structured questionnaire after a service of a pharmacist was delivered, and their drugs dispensed. Uni- and multi-variate regression methods were used for processing the data. In total 330 patients participated in the study. A higher body mass index (OR = 1.113, p = 0.003), living at a higher altitude (OR = 1.725, p = 0.000), anaemia (OR = 4.221, p = 0.008), and intestinal infection in the last 3 months (OR = 2.801, p = 0.006) increased the risk of GI complaints in patients on MTF therapy, while the use of statins was protective (OR = 0.204, p = 0.016). Each case of MTF intolerance should be carefully investigated for risk and protective factors, which could be potentially eliminated or augmented, respectively, and MTF withdrawal avoided.

Predictors of Metformin Side Effects in Patients with Newly Diagnosed Type 2 Diabetes Mellitus

Introduction Metformin has become the first-line agent for the treatment of type 2 diabetes mellitus (T2DM) in several international guidelines. Up to 25% of patients suffer from gastrointestinal side-effects, with approximately 5% unable to tolerate metformin at all.

Objective We aimed to study the effect of variables that may influence the development of metformin side effects and/or intolerance.

Method A prospective study was conducted from April 1, 2021 to March 30, 2022. One-hundred and forty-eight patients newly diagnosed with T2DM were enrolled in the study, and divided into two groups—those who were escalate to the maximum dose of metformin over 2 weeks (n = 43) and the other group over 4 weeks (n = 105). We studied the variables that may affect the development of side effects including age, gender, body mass index (BMI), lipid profile, glycemic level, and the use of other antidiabetic medications besides the duration of dose escalation.

Results Total number of patients who developed side effects was 59 (39.9%). Twenty-four (55.8%) and 35 (33.3%) patients were put in the rapid and slow escalation groups, respectively. Twenty-six (17.6%) patients developed diarrhea that was the most common side effect. Two (2.7%) men and ten women (13.5%) had stopped metformin due to severe side effects developed after initiation (p = 0.016). The mean BMI for the patients who discontinued metformin was 34.7 ± 4.1 kg/m2 in the rapid escalation arm and 31.6 ± 3.3 kg/m2 in the slow escalation arm (p = 0.003). The mean of fasting blood glucose for the patients who discontinued metformin in the rapid and slow escalation arms was 200.6 ± 25.6 and 173.4 ± 36.5 mg/dL, respectively (p = 0.022).

Conclusion The severity of metformin side effects is higher in women than in men, making more women to discontinue the drug. Besides, a higher fasting blood sugar and BMI are associated with a higher rate of discontinuation. A rapid dose escalation is associated with a higher frequency of side effects. Diarrhea is the commonest side effect encountered.

Clinical Application of Metformin Use in Anhui Province, China: A Cross-Sectional Study

Purpose

Given the importance of metformin, reasonable utilization is essential. We designed a cross-sectional survey on physicians' attitude and clinical application of metformin in Anhui Province, China.

Methods

The survey was distributed via an electronic questionnaire among endocrinologists and general practitioners. Seven representative questions were used to evaluate professional levels.

Results

Among the 477 valid responses, 72.75% of the respondents preferred to prescribe metformin extended-release, while only 34.38% of them would prescribe metformin extended-release at the correct frequency. More than half of the respondents thought that estimated glomerular filtration rate ˂ 45 mL/min/1.73 m² should be the contraindication of metformin prescription. Less than 10% of the physicians selected correct responses for two questions regarding metformin usage and contrast agent. Physicians with higher levels of hospital grades, education background and professional titles as well as working in general hospitals and in the Department of Endocrinology achieved high scores (P˂0.05). Logistic regression showed that department was an independent predictor for high scores.

Conclusion

Physicians, especially non-endocrinologists, are not at a professional level for prescribing metformin. Physicians should be highly vigilant in terms of standardized prescription for metformin. The guidelines or consensuses about diabetes care for physicians should be promoted.

Prevalence of Gastrointestinal Symptoms in Chinese Community-Dwelling Adults with and without Diabetes

Background: Gastrointestinal symptoms have been reported to occur frequently in diabetes, but their prevalence in Chinese community-dwelling individuals with diabetes is unknown. The present study aimed to address this issue and explore the risk factors for gastrointestinal symptoms. Methods: A total of 1304 community-dwelling participants (214 with diabetes, 360 with prediabetes and 730 with normoglycemia) were surveyed for gastrointestinal symptoms using the Diabetes Bowel Symptom Questionnaire. Logistic regression analyses were applied to identify risk factors for gastrointestinal symptoms. Results: Of the overall study population, 18.6% reported at least one gastrointestinal symptom, without a significant difference between subjects with normoglycemia (17.7%), prediabetes (19.7%) and diabetes (20.1%). In all three groups, lower gastrointestinal symptoms, particularly diarrhea and constipation, were the most frequent. There was an interaction between age (≥65 years) and diabetes on the prevalence of at least one gastrointestinal symptom (p = 0.01) and of constipation (p = 0.004), with these being most frequent in subjects with diabetes aged ≥ 65 years. After multivariable adjustment, female gender and older age were associated with increased odds of at least one gastrointestinal symptom, specifically lower gastrointestinal symptoms. Older age was also associated with an increase in upper gastrointestinal symptoms. Conclusions: Gastrointestinal symptoms are common in Chinese community-dwelling adults with and without diabetes. Females, and the elderly with diabetes, are at an increased risk of symptoms.

Gastrointestinal symptoms in patients with diabetes mellitus and non-diabetic: A cross-sectional study in north of Iran

BACKGROUND AND AIM

Gastrointestinal (GI) symptoms are common in patients with diabetes mellitus (DM), which involved in high cost of health care and low quality of life. The aim of this study to investigate the prevalence of GI symptoms in diabetic patients referred to the Gastrointestinal and Liver Diseases Research Center (GLDRC), Guilan University of Medical Sciences (Rasht, Iran) using a validated questionnaire.

METHODS

In this descriptive, cross-sectional study, 255 diabetic patients and 255 non-diabetic subjects were recruited. Participants were randomly selected. The questionnaire recorded GI symptoms among the study population.

RESULTS

GI symptoms were reported in 91.4% of diabetic patients, and 42.1% of them were male. The common GI symptoms in diabetic patients were flatulence (33.0%), followed by retrosternal pain (14.9%), belching (13.7%), postprandial fullness (12.5%), and constipation (11.4%). Retrosternal pain, constipation, flatulence, loss of appetite, and abdominal distention were more prevalent in diabetic women than men.

CONCLUSIONS

DM is associated with high prevalence rate of upper and lower GI symptoms. This effect may be linked to gender and poor glycemic control in diabetic patients, but not to type and duration of diabetes.

Comparative effectiveness of metformin monotherapy in extended release and immediate release formulations for the treatment of type 2 diabetes in treatment-naïve Chinese patients: Analysis of results from the CONSENT trial

AIMS

Metformin treatment for type 2 diabetes mellitus (T2DM) can be limited by gastrointestinal (GI) adverse events (AEs), resulting in treatment discontinuation. We investigated whether once-daily metformin extended release (XR) is superior in terms of GI tolerability, with non-inferior efficacy, compared with thrice-daily metformin immediate release (IR) in treatment-naïve Chinese patients with T2DM.

MATERIALS AND METHODS

This prospective, open-label, randomized, multicentre, phase IV interventional study enrolled Chinese T2DM patients to receive either metformin XR or metformin IR with a 2-week screening period, a 16-week treatment period and a 2-week follow-up period without treatment. Co-primary endpoints were a non-inferiority assessment of metformin XR vs metformin IR in glycated haemoglobin (HbA1c) least squares mean (LSM) change from baseline to week 16 and the superiority of GI tolerability for metformin XR vs metformin IR.

RESULTS

Overall, 532 patients were randomized to metformin IR (n = 267) or metformin XR (n = 265). The HbA1c LSM change was -1.61% and -1.58% in each group, respectively (LSM difference, 0.03; 95% confidence interval [CI], -0.10, 0.17). Incidences of drug-related AEs were 26.5% (n = 66) in the metformin IR-only group and 32.2% (n = 85) in the metformin XR-only group, and GI AEs were 23.8% and 22.3% in each group, respectively (difference, -1.52; 95% CI, -8.60, 5.56). The treatment difference met the predefined non-inferiority upper CI margin of 0.4% in HbA1c.

CONCLUSIONS

Metformin XR was non-inferior to metformin IR for the LSM change in HbA1c from baseline to week 16 and not superior to metformin IR for overall GI AE incidence during treatment of Chinese T2DM patients.

Understanding and overcoming metformin gastrointestinal intolerance

Metformin is the most widely prescribed drug for patients with type 2 diabetes mellitus and the first-line pharmacological option as supported by multiple international guidelines, yet a rather large proportion of patients cannot tolerate metformin in adequate amounts because of its associated gastrointestinal (GI) adverse events (AEs). GI AEs typically encountered with metformin therapy include diarrhoea, nausea, flatulence, indigestion, vomiting and abdominal discomfort, with diarrhoea and nausea being the most common. Although starting at a low dose and titrating slowly may help prevent some GI AEs associated with metformin, some patients are unable to tolerate metformin at all and it may also be difficult to convince patients to start metformin again after a bout of GI AEs. Despite this clinical importance, the underlying mechanisms of the GI intolerance associated with metformin are poorly known. In the present review, we discuss: the epidemiology of metformin-associated GI intolerance and its underlying mechanisms; genotype variability and associated factors affecting metformin GI intolerance, such as comorbidities, co-medications and bariatric surgery; clinical consequences and therapeutic strategies to overcome metformin GI intolerance. These strategies include appropriate titration of immediate-release metformin, use of extended-release metformin, the promise of delayed-release metformin and gut microbiome modulators, as well as alternative pharmacological therapies when metformin cannot be tolerated at all. Given the available data, all efforts should be made to maintain metformin before considering a shift to another drug therapy.

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.