Metformin and risk of chronic obstructive pulmonary disease in diabetes patients

COPD and cardiovascular risk

Chronic Obstructive Pulmonary Disease (COPD) usually presents joined to other pathologies we call comorbidities. The more frequent of them are those related to cardiovascular risk, either its risk factors or its clinical manifestations. Cardiovascular risk of these patients grows up with the severity of the airflow obstruction, specially during and after an exacerbation of COPD. Patients with COPD have between 2 and 5 times more risk of ischaemic heart disease than people without COPD, even after adjusting for cofounding factors. Cardiovascular diseases are up to the second cause of mortality in these patients, close to those due to the lung disease. Although COPD is associated to several cardiovascular risk factors such as tobacco, arterial hypertension or Diabetes Mellitus, they don't explain all the excess in cardiovascular risk these patients have. Despite that excess of cardiovascular risk in COPD patients, most widely used cardiovascular risk scores don't include COPD as a risk factor itself, so global risk is understimated in these patients. In this review, we make a bibliography revision of the avaliable evidence about COPD and cardiovascular risk factors as well as the excess of cardiovascular risk COPD itself involves.

Causal relationship between type 2 diabetes and common respiratory system diseases: a two-sample Mendelian randomization analysis

Background

Type 2 diabetes (T2D) frequently co-occurs with respiratory system diseases such as chronic obstructive pulmonary disease (COPD), bronchial asthma, lung cancer, interstitial lung disease, and pulmonary tuberculosis. Although a potential association is noted between these conditions, the available research is limited.

Objective

To investigate the causal relationship between patients with T2D and respiratory system diseases using two-sample Mendelian randomization analysis.

Methods

Causal relationships were inferred using a two-sample Mendelian randomization (MR) analysis based on publicly available genome-wide association studies. We employed the variance inverse-weighted method as the primary analytical approach based on three key assumptions underlying MR analysis. To bolster the robustness and reliability of our results, we utilized MR Egger's intercept test to detect potential pleiotropy, Cochran's Q test to assess heterogeneity, funnel plots to visualize potential bias, and "leave-one-out" sensitivity analysis to ensure that our findings were not unduly influenced by any single genetic variant.

Result

The inverse variance weighted (IVW) analysis indicated a causal relationship between T2D and COPD [Odds Ratio (OR) = 0.87; 95% Confidence Interval (CI) = 0.82-0.96; p < 0.05]. No significant heterogeneity or pleiotropy were observed through their respective tests (p > 0.05), and the statistical power calculations indicated that the results were reliable. The IVW analysis showed a negative causal relationship between T2D and bronchial asthma [OR = 0.85; 95% CI = 0.81-0.89; p < 0.05]. However, the IVW under the random-effects model indicated heterogeneity (p < 0.05), suggesting instability in the results and requiring cautious interpretation. The study found a positive causal relationship between T2D and pulmonary tuberculosis (OR = 1.24, 95% CI = 1.05-1.45, p < 0.05). However, they exhibited pleiotropy (p < 0.05), indicating their instability. No correlation between T2D and interstitial lung disease or lung cancer was observed.

Conclusion

T2D is negatively associated with COPD, suggesting that T2D may reduce the risk of developing COPD. A negative causal relationship between T2D and bronchial asthma has been observed, but the results exhibit heterogeneity. There is a positive causal relationship between T2D and pulmonary tuberculosis, yet the findings suggest the presence of pleiotropy. No significant causal relationship between T2D and lung cancer or interstitial lung disease was observed.

Construction of a ceRNA network and screening of potential biomarkers and molecular targets in male smokers with chronic obstructive pulmonary disease

BACKGROUND

Circular RNAs (circRNAs) play an important role in the occurrence and development of diseases. However, the role of circRNAs in male smokers with chronic obstructive pulmonary disease (COPD) remains unclear.

METHODS

Stable COPD patients and healthy controls were recruited. Peripheral blood mononuclear cells (PBMCs) were extracted. After high-throughput RNA sequencing (RNA-Seq) of PBMCs, a bioinformatics method was used to analyse differentially expressed (DE) circRNAs (DEcircRNAs) and mRNAs (DEmRNAs).

RESULTS

Total of 114 DEcircRNAs and 58 DEmRNAs were identified. Functional enrichment analysis showed that processes related to COPD include the regulation of interleukin (IL)-18, IL-5 and the NLRP3 inflammasome; differentiation of T helper type 1 (Th1), Th2, and Th17 cells, and the AMPK, Wnt, JAK-STAT, and PI3K-Akt signalling pathways. In the protein-protein interaction (PPI) network, the core genes were MYO16, MYL4, SCN4A, NRCAM, HMCN1, MYOM2, and IQSEC3. Small-molecule prediction results revealed potential drugs for the COPD treatment. Additionally, the circRNA-miRNA-mRNA competitive endogenous RNA (ceRNA) regulatory network was constructed.

CONCLUSION

This study identified a set of dysregulated circRNAs and mRNAs and revealed potentially important genes, pathways, new small-molecule drugs and ceRNA regulatory networks in male smokers with COPD. These circRNAs might be prospective biomarkers or potential molecular targets of the ceRNA mechanism for COPD.

Extrapulmonary Comorbidities Associated with Chronic Obstructive Pulmonary Disease: A Review

Most patients with chronic obstructive pulmonary disease (COPD) suffer from at least one additional, clinically relevant chronic disease. To a degree, the high global prevalence and mortality rate of COPD is closely related to its extrapulmonary effects. Moreover, the various of comorbidities of COPD and itself interact with each other, resulting in diverse clinical manifestations and individual differences, and thus further influencing the prognosis as well as healthcare burden of COPD patients. This is closely related to the common risk factors of chronic diseases (aging, smoking, inactivity, etc.). Additionally, some pathophysiological mechanisms caused by COPD, including the systemic inflammatory response, hypoxia, oxidative stress, and others, also have an impact on other systems. But comprehensive management and medical interventions have not yet been established. The clinicians should improve their knowledge and skills in diagnosing as well as treating the comorbidities of COPD, and then aim to develop more individualized, efficient diagnostic and therapeutic strategies for different patients to achieve greater clinical benefits. In this article, we will review the risk factors, mechanisms, and treatment strategies for extrapulmonary comorbidities in chronic obstructive pulmonary disease, including cardiovascular diseases, diabetes, anemia, osteoporosis, emotional disorders, and gastroesophageal reflux disease.

Effect of Metformin on Lower Urinary Tract Symptoms in Male Patients with Type 2 Diabetes Mellitus: A Retrospective Cohort Study in Taiwan

PURPOSE

This study investigated the risk of lower urinary tract symptoms (LUTS)/benign prostatic hyperplasia (BPH) associated with metformin use.

MATERIALS AND METHODS

We used the database of Taiwan's National Health Insurance to create 9,833 pairs of ever users and never users of metformin matched on propensity score. They were males with a new diagnosis of type 2 diabetes during 1999-2005. The incidence of LUTS/BPH was calculated from January 1, 2006 until December 31, 2011. We estimated hazard ratios by Cox regression weighted on propensity score.

RESULTS

There were 515 incident cases in ever users after a median follow-up of 5.4 years (incidence rate: 11.24 per 1,000 person-years) and 682 cases in never users after 5.2 years (15.92 per 1,000 person-years). The hazard ratio (HR) that compared ever to never users was 0.69 (95% confidence interval [CI], 0.62-0.78). The HRs that compared ever users categorized into quartiles of cumulative duration (<19.33, 19.33-41.56, 41.57-67.17, and >67.17 mo) to never users were 1.02 (0.84-1.23), 1.01 (0.86-1.20), 0.57 (0.47-0.69), and 0.40 (0.32-0.49), respectively. For the quartiles of cumulative dose of <582.00, 582.00-1,361.00, 1,361.01-2,449.00, and >2,449.00 g, the respective HRs were 1.03 (0.85-1.24), 0.96 (0.81-1.13), 0.60 (0.49-0.72), and 0.40 (0.32-0.50). The lower risk was significant in all quartiles of defined daily dose. However, a larger daily dose was associated with a greater risk reduction. There were no significant interactions between metformin and other antidiabetic drugs. Patients who used rosiglitazone and/or pioglitazone without metformin had a significantly higher risk (HR, 1.33; 95% CI, 1.09-1.63) and a combination with metformin attenuated such an adverse impact (HR, 0.78; 95% CI, 0.66-0.91).

CONCLUSIONS

A significantly lower risk of LUTS/BPH is observed in males with type 2 diabetes who use metformin.

Mechanisms Linking COPD to Type 1 and 2 Diabetes Mellitus: Is There a Relationship between Diabetes and COPD?

Chronic obstructive pulmonary disease (COPD) patients frequently suffer from multiple comorbidities, resulting in poor outcomes for these patients. Diabetes is observed at a higher frequency in COPD patients than in the general population. Both type 1 and 2 diabetes mellitus are associated with pulmonary complications, and similar therapeutic strategies are proposed to treat these conditions. Epidemiological studies and disease models have increased our knowledge of these clinical associations. Several recent genome-wide association studies have identified positive genetic correlations between lung function and obesity, possibly due to alterations in genes linked to cell proliferation; embryo, skeletal, and tissue development; and regulation of gene expression. These studies suggest that genetic predisposition, in addition to weight gain, can influence lung function. Cigarette smoke exposure can also influence the differential methylation of CpG sites in genes linked to diabetes and COPD, and smoke-related single nucleotide polymorphisms are associated with resting heart rate and coronary artery disease. Despite the vast literature on clinical disease association, little direct mechanistic evidence is currently available demonstrating that either disease influences the progression of the other, but common pharmacological approaches could slow the progression of these diseases. Here, we review the clinical and scientific literature to discuss whether mechanisms beyond preexisting conditions, lifestyle, and weight gain contribute to the development of COPD associated with diabetes. Specifically, we outline environmental and genetic confounders linked with these diseases.

Senescence: Pathogenic Driver in Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) is recognized as a disease of accelerated lung aging. Over the past two decades, mounting evidence suggests an accumulation of senescent cells within the lungs of patients with COPD that contributes to dysregulated tissue repair and the secretion of multiple inflammatory proteins, termed the senescence-associated secretory phenotype (SASP). Cellular senescence in COPD is linked to telomere dysfunction, DNA damage, and oxidative stress. This review gives an overview of the mechanistic contributions and pathologic consequences of cellular senescence in COPD and discusses potential therapeutic approaches targeting senescence-associated signaling in COPD.

COPD and Diabetes Mellitus: Down the Rabbit Hole

Abstract:

One of the important comorbidities that has a longstanding research history in COPD is diabetes. Although there are multiple studies on COPD and diabetes, the exact links between these two conditions are still controversial. The exact prevalence of diabetes in COPD varies between 2 and 37 %. The true nature of this relationship is complex and may be partially related to the tradi-tional risk factors for diabetes such as smoking, cardiovascular disease and use of steroids. Howev-er, COPD is a disease that has multiple phenotypes and is no longer regarded as a homogeneous condition. It seems that some COPD patients who overlap with asthma or the obese phenotype are at a particular risk for T2DM. The aim of this review is to analyze the prevalence, risk factors and possible interactions between COPD and diabetes mellitus.

Pathophysiological aspects of insulin resistance in Atrial Fibrillation: novel therapeutic approaches

Background

Insulin resistance is associated with metabolic disorders including diabetes, obesity, hypertension, and inflammation which are the risk factors for Atrial Fibrillation. Many studies have reported that type 2 diabetes and AF are related and also their prevalence is increasing globally. Moreover, insulin resistance begins the type 2 diabetes.

Main body

This review explains the pathophysiological aspects of insulin resistance in AF patients and discusses the drugs that are used to manage insulin resistance including Biguanides (metformin), thiazolidinediones (TZDs) [Pioglitazone, rosiglitazone], Sodium-glucose cotransporter 2 (SGLT2) inhibitors, Concentrated Insulin Products, Dipeptidyl peptidase-4 (DPP-4) Inhibitors, Glucagon-like peptide 1 (GLP-1) receptor Agonists, Pramlintide, Sulfonylureas, Meglitinides, α-Glucosidase Inhibitors, Colesevelam, Bromocriptine. This review will highlight a few major drugs that played a significant role in AF patients. For this purpose, many databases were used for reviewing the literature and keywords are used such as Insulin Resistance, Pathophysiology, Atrial Fibrillation, and Drugs.

Conclusion

This review article concludes that insulin resistance is related to AF. It also provides an outlook on the recent pathophysiological aspects of insulin resistance in AF; however, more studies are needed to clarify the management of insulin resistance in AF patients to prevent the development of type 2 diabetes.

The Effect of Metformin on Male Reproductive Function and Prostate: An Updated Review

Metformin is the first-line oral antidiabetic drug that shows multiple pleiotropic effects of anti-inflamation, anti-cancer, anti-aging, anti-microbia, anti-atherosclerosis, and immune modulation. Metformin's effects on men's related health are reviewed here, focusing on reproductive health under subtitles of erectile dysfunction (ED), steroidogenesis and spermatogenesis; and on prostate-related health under subtitles of prostate specific antigen (PSA), prostatitis, benign prostate hyperplasia (BPH), and prostate cancer (PCa). Updated literature suggests a potential role of metformin on arteriogenic ED but controversial and contradictory effects (either protective or harmful) on testicular functions of testosterone synthesis and spermatogenesis. With regards to prostate-related health, metformin use may be associated with lower levels of PSA in humans, but its clinical implications require more research. Although there is a lack of research on metform's effect on prostatitis, it may have potential benefits through its anti-microbial and anti-inflammatory properties. Metformin may reduce the risk of BPH by inhibiting the insulin-like growth factor 1 pathway and some but not all studies suggest a protective role of metformin on the risk of PCa. Many clinical trials are being conducted to investigate the use of metformin as an adjuvant therapy for PCa but results currently available are not conclusive. While some trials suggest a benefit in reducing the metastasis and recurrence of PCa, others do not show any benefit. More research works are warranted to illuminate the potential usefulness of metformin in the promotion of men's health.

Therapeutic approaches targeting molecular signaling pathways common to diabetes, lung diseases and cancer

Diabetes mellitus (DM), is the most common metabolic disease and is characterized by sustained hyperglycemia. Accumulating evidences supports a strong association between DM and numerous lung diseases including chronic obstructive pulmonary disease (COPD), fibrosis, and lung cancer (LC). The global incidence of DM-associated lung disorders is rising and several ongoing studies, including clinical trials, aim to elucidate the molecular mechanisms linking DM with lung disorders, in particular LC. Several potential mechanisms, including hyperglycemia, hyperinsulinemia, glycation, inflammation, and hypoxia, are cited as plausible links between DM and LC. In addition, studies also propose a connection between the use of anti-diabetic medications and reduction in the incidence of LC. However, the exact cause for DM associated lung diseases especially LC is not clear and is an area under intense investigation. Herein, we review the biological links reported between DM and lung disorders with an emphasis on LC. Furthermore, we report common signaling pathways (eg: TGF-β, IL-6, HIF-1, PDGF) and miRNAs that are dysregulated in DM and LC and serve as molecular targets for therapy. Finally, we propose a nanomedicine based approach for delivering therapeutics (eg: IL-24 plasmid DNA, HuR siRNA) to disrupt signaling pathways common to DM and LC and thus potentially treat DM-associated LC. Finally, we conclude that the effective modulation of commonly regulated signaling pathways would help design novel therapeutic protocols for treating DM patients diagnosed with LC.

Metformin and Risk of Malignant Brain Tumors in Patients with Type 2 Diabetes Mellitus

The risk of malignant brain tumors associated with metformin use has rarely been investigated in humans. This retrospective cohort study investigated such an association. Patients with new-onset type 2 diabetes mellitus diagnosed from 1999 to 2005 in the nationwide database of Taiwan's national health insurance were used to enroll study subjects. We first identified an unmatched cohort of 153,429 ever users and 16,222 never users of metformin. A cohort of 16,222 ever users and 16,222 never users matched on propensity score was then created from this unmatched cohort. All patients were followed up from 1 January 2006 until 31 December 2011. The incidence density was calculated and hazard ratios were derived from Cox regression incorporated with the inverse probability of treatment weighting using a propensity score. The results showed that 27 never users and 155 ever users developed malignant brain tumors in the unmatched cohort. The incidence rate was 37.11 per 100,000 person-years in never users and 21.39 per 100,000 person-years in ever users. The overall hazard ratio comparing ever users versus never users was 0.574 (95% confidence interval: 0.381-0.863). The respective hazard ratios comparing the first (<27.13 months), second (27.13-58.33 months), and third (>58.33 months) tertiles of cumulative duration of metformin therapy versus never users were 0.897 (0.567-1.421), 0.623 (0.395-0.984), and 0.316 (0.192-0.518). In the matched cohort, the overall hazard ratio was 0.317 (0.149-0.673) and the respective hazard ratios were 0.427 (0.129-1.412), 0.509 (0.196-1.322), and 0.087 (0.012-0.639) for the first, second, and third tertile of cumulative duration of metformin therapy. In conclusion, this study shows a risk reduction of malignant brain tumors associated with metformin use in a dose-response pattern. The risk reduction is more remarkable when metformin has been used for approximately 2-5 years.

The Relationship between Diabetes Mellitus and Gastric Cancer and the Potential Benefits of Metformin: An Extensive Review of the Literature

The objective of this review is to summarize the findings of published research that investigated the relationship between diabetes mellitus and gastric cancer (GCa) and the potential benefits of metformin on GCa. Related literature has been extensively reviewed, and findings from studies investigating the relationship between diabetes mellitus and GCa suggest that hyperglycemia, hyperinsulinemia and insulin resistance are closely related to the development of GCa. Although not supported by all, most observational studies suggest an increased risk of GCa in patients with type 2 diabetes mellitus, especially in women and in Asian populations. Incidence of second primary malignancy diagnosed after GCa is significantly higher in diabetes patients. Diabetes patients with GCa may have more complications after gastrectomy or chemotherapy and they may have a poorer prognosis than patients with GCa but without diabetes mellitus. However, glycemic control may improve in the diabetes patients with GCa after receiving gastrectomy, especially after procedures that bypass the duodenum and proximal jejunum, such as Roux-en-Y gastric bypass or Billroth II reconstruction. The potential links between diabetes mellitus and GCa may involve the interactions with shared risk factors (e.g., obesity, hyperglycemia, hyperinsulinemia, insulin resistance, high salt intake, smoking, etc.), Helicobacter pylori (HP) infection, medications (e.g., insulin, metformin, statins, aspirin, proton pump inhibitors, antibiotics, etc.) and comorbidities (e.g., hypertension, dyslipidemia, vascular complications, heart failure, renal failure, etc.). With regards to the potential benefits of metformin on GCa, results of most observational studies suggest a reduced risk of GCa associated with metformin use in patients with T2DM, which can be supported by evidence derived from many in vitro and animal studies. Metformin use may also reduce the risk of HP infection, an important risk factor of GCa. In patients with GCa, metformin users may have improved survival and reduced recurrence. More studies are required to clarify the pathological subtypes/anatomical sites of GCa associated with type 2 diabetes mellitus or prevented by metformin, to confirm whether GCa risk can also be increased in patients with type 1 diabetes mellitus and to explore the possible role of gastric microbiota in the development of GCa.

Metformin Use Is Associated With a Lower Incidence of Hospitalization for Atrial Fibrillation in Patients With Type 2 Diabetes Mellitus

Background: The effect of metformin on the risk of atrial fibrillation (AF) requires confirmation. This retrospective cohort study compared the incidence of hospitalization for AF in ever and never users of metformin. Methods: Patients with newly diagnosed type 2 diabetes mellitus during 1999-2005 were enrolled from Taiwan's National Health Insurance database. Analyses were conducted in both an unmatched cohort of 173,398 ever users and 21,666 never users and in a propensity score-matched cohort of 21,662 pairs of ever and never users. They were free from a diagnosis of AF before January 1, 2006 and were followed up until December 31, 2011. Hazard ratios were estimated by Cox regression incorporated with the inverse probability of treatment weighting using the propensity score. Results: A total of 303 ever users and 86 never users in the unmatched cohort and 56 ever users and 86 never users in the matched cohort developed hospitalization for AF during follow-up. The respective incidence rates were 37.72 and 92.45 per 100,000 person-years in the unmatched cohort and were 56.98 and 92.46 per 100,000 person-years in the matched cohort. The hazard ratio for ever vs. never users was 0.405 (95% confidence interval: 0.319-0.515) in the unmatched cohort and 0.617 (0.441-0.864) in the matched cohort. Hazard ratios for the tertiles of cumulative duration of metformin therapy vs. never users showed a dose-response effect. The findings were consistent in sensitivity analyses. Conclusion: Metformin use is associated with a lower risk of hospitalization for AF in patients with type 2 diabetes mellitus.

Oral treatment for diabetes using α-glucosidase inhibitors was a risk factor for chronic obstructive pulmonary disease: a cohort study

Objectives: Currently, diabetes mellitus (DM) and chronic obstructive pulmonary disease (COPD) have proven to be risk factors for each other. This study aimed to determine the risk relationship between COPD and five common oral medications for DM among patients with DM. Methods: This population-based cohort study was conducted from 2008 to 2013. Patient data were retrieved from the Longitudinal Health Insurance Database (LHID) of the National Health Insurance Research Database (NHIRD). After pairing by gender, age, and index date, time-to-event analysis and multiple regression analysis were performed to determine the factors associated with COPD in patients taking oral medication for DM, including age, gender, income, and comorbidities. We identified 1,028 patients who took oral medication for DM and 1,028 controls who did not take oral medication for DM. Results: We observed that the use of α-glucosidase inhibitors was associated with a higher risk of COPD (hazard ratio [HR]: 1.964, 95% confidence interval [CI]: 1.207-2.380). Furthermore, compared with the control group, α-glucosidase inhibitor users had a higher risk of COPD (HR: 2.295, 95% CI: 1.304-4.038), and no significant difference was observed in other oral medications for DM. Conclusions: Based on present results, we could suggest that patients with DM who used α-glucosidase inhibitors are probably a higher risk of COPD. We recommend that in the future, treatment with α-glucosidase inhibitors upregulate the occurrence of COPD might through gastrointestinal side effects and malnutrition.

Effects of different doses of metformin on bone mineral density and bone metabolism in elderly male patients with type 2 diabetes mellitus

BACKGROUND

Diabetes is a chronic disease, which may cause various complications. Patients with diabetes are at high risk of bone and joint disorders, such as osteoporosis and bone fractures. In addition, it became widely accepted that diabetes has an important impact on bone metabolism. Metformin is a commonly used and effective first-line treatment for type 2 diabetes. Some glucose-lowering agents have been found to have an effect on bone metabolism. The present study explored if different doses of metformin have an effect on bone mineral density (BMD) and bone metabolism in type 2 diabetes.

AIM

To investigate the effects of different doses of metformin on BMD and bone metabolism in elderly male patients with type 2 diabetes mellitus.

METHODS

A total of 120 elderly male outpatients with type 2 diabetes mellitus who were admitted to our hospital were included in the study from July 2018 to June 2019. They were randomly assigned to an experimental group and a control group with 60 patients in each group. Patients in the experimental group were given high dose metformin four times a day 0.5 g each time for 12 wk. Patients in the control group were given low dose metformin orally twice a day 0.5 g each time for 12 wk. The changes in bone mineral density and bone metabolism before and after treatment and the efficacy rate of the treatment were compared between the two groups.

RESULTS

There was no significant difference in the efficacy rate between the two groups (P > 0.05). Before the treatment, there was no significant difference in BMD and bone metabolism between the two groups (P > 0.05). However, after the treatment, BMD and bone metabolism were improved in the two groups. Moreover, BMD and 25-hydroxyvitamin D were significantly higher in the experimental group than in the control group, and N-terminal/midregion and β-isomerized C-terminal telopeptides were significantly lower in the experimental group than in the control group (all P < 0.05). There was no significant difference in the incidence of adverse reactions between the two groups (P > 0.05).

CONCLUSION

Both high and low dose metformin can effectively control the blood glucose levels in elderly male patients with type 2 diabetes mellitus. However, the benefits of high dose metformin in improving BMD and bone metabolism level was more obvious in patients with type 2 diabetes mellitus.

Diabetes Mellitus and Chronic Obstructive Pulmonary Disease: An Overview

Chronic obstructive pulmonary disease (COPD) is a common disease with an increasing prevalence, characterised by persistent respiratory symptoms and airflow limitation. Apart from cigarette smoking, certain occupational and environmental exposures, low socioeconomic status and genetic factors may contribute to the pathogenesis of COPD. Comorbidities, e. g. diabetes mellitus (DM), can negatively affect quality of life, COPD outcomes and cardiovascular risk. The present narrative review considers the potential links between COPD and DM, such as systemic inflammation, oxidative stress, hypoxaemia and hyperglycaemia. The effects of antidiabetic drugs on lung function and COPD outcomes, as well as the possibility of common therapeutic modalities are also briefly considered. Further research is needed in this field to elucidate these relationships as well as their potential clinical implications in daily practice.

Reduced mortality from lower respiratory tract disease in adult diabetic patients treated with metformin

BACKGROUND AND OBJECTIVE

Chronic lower respiratory diseases (CLRD) increase the risk of type 2 diabetes, which in turn may worsen lung function. Metformin, a common antidiabetic with anti-inflammatory and antioxidant properties, may improve respiratory outcomes. Therefore, we examined the association of metformin use with the risk of mortality from CLRD.

METHODS

We analysed data from the National Health and Nutrition Examination Survey during 1988-1994 and 1999-2010 for participants aged 40 years or older who had diabetes and were followed up for mortality through 2011. Information on prescription medicine was collected at baseline and CLRD-related mortality during follow-up was defined using the 10th Revision of the International Classification of Diseases (ICD-10). Cox proportional hazards modelling was used to determine the mortality hazard ratio (HR) associated with metformin use, adjusting for relevant covariates.

RESULTS

A total of 5266 participants with a median follow-up of 6.1 years were included. The prevalence of metformin use was 31.9% and 1869 participants died during follow-up, including 72 of CLRD. In the adjusted Cox proportional regression analysis, metformin was associated with a decreased risk of CLRD mortality in the overall population (HR: 0.39, 95% CI: 0.15-0.99) and among participants with baseline CLRD (HR: 0.30, 95% CI: 0.10-0.93), after adjusting for age, gender, race/ethnicity, cigarette smoking, body mass index, current asthma and chronic obstructive pulmonary disease (COPD), insulin and other diabetic medications, and glycohaemoglobin level. We found no association between other antidiabetic medications and CLRD mortality.

CONCLUSION

In this sample representative of the U.S. population, metformin was associated with lower CLRD mortality in adults with diabetes.

Effects of metformin use on total mortality in patients with type 2 diabetes and chronic obstructive pulmonary disease: A matched-subject design

BACKGROUNDS

Few studies have investigated the therapeutic effects of metformin in patients with type 2 diabetes mellitus (T2DM) and chronic obstructive pulmonary disease (COPD). We compared the risk of all-cause mortality between metformin users and nonusers.

METHODS

We conducted a retrospective cohort study for patients with T2DM and COPD who were enrolled between January 1, 2000 and June 30, 2012. Individuals with exacerbated symptoms who were hospitalized or sent to the emergency department (ED) were identified as having exacerbated COPD; outpatient claims were identified as having stable COPD. A total of 40,597 metformin users and 39,529 nonusers comprised the cohort of stable COPD; 14,001 metformin users and 21,613 nonusers comprised the cohort of exacerbated COPD. Users and nonusers were matched using propensity score (1:1). Our primary outcome was all-cause mortality.

RESULTS

A total of 19,505 metformin users were matched to 19,505 nonusers in the cohort of diabetes with stable COPD. The mean follow-up time was 3.91 years. All-cause mortality was reported in 1326 and 1609 metformin users and nonusers, respectively. After multivariate adjustment, metformin users had lower risk of mortality (adjusted hazard ratio [aHR] = 0.84, p < 0.0001). Metformin users had significantly lower risk of noncardiovascular death (aHR = 0.86, p = 0.0008). A total of 7721 metformin users were matched to 7721 nonusers in the cohort of diabetes with exacerbated COPD. The mean follow-up time was 3.18 years. All-cause mortality was reported in 1567 and 1865 metformin users and nonusers, respectively. After multivariate adjustment, metformin users had significantly lower risk of mortality (aHR = 0.89, p = 0.002) and cardiovascular death (aHR = 0.70, p = 0.01).

CONCLUSION

This large-series, nationwide cohort study demonstrated that metformin use could significantly lower the risk of all-cause mortality in patients with T2DM and either stable or exacerbated COPD.