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

A Critical Review on the Long-Term COVID-19 Impacts on Patients With Diabetes

BACKGROUND

The world is currently grappling with the potentially life-threatening coronavirus disease 2019 (COVID-19), marking it as the most severe health crisis in the modern era. COVID-19 has led to a pandemic, with the World Health Organization (WHO) predicting that individuals with diabetes are at a higher risk of contracting the virus compared to the general population. This review aims to provide a practical summary of the long-term impacts of COVID-19 on patients with diabetes. Specifically, it focuses on the effects of SARS-CoV-2 on different types of diabetic patients, the associated mortality rate, the underlying mechanisms, related complications, and the role of vitamin D and zinc in therapeutic and preventive approaches.

METHODS

Relevant literature was identified through searches on PubMed, Web of Science, and Science Direct in English, up to April 2023.

RESULTS

COVID-19 can lead to distressing symptoms and pose a significant challenge for individuals living with diabetes. Older individuals and those with pre-existing conditions such as diabetes, coronary illness, and asthma are more susceptible to COVID-19 infection. Managing COVID-19 in individuals with diabetes presents challenges, as it not only complicates the fight against the infection but also potentially prolongs the recovery time. Moreover, the virus may thrive in individuals with high blood glucose levels. Various therapeutic approaches, including antidiabetic drugs, are available to help prevent COVID-19 in diabetic patients.

CONCLUSIONS

Diabetes increases the morbidity and mortality risk for patients with COVID-19. Efforts are globally underway to explore therapeutic interventions aimed at reducing the impact of diabetes on COVID-19.

Metformin use is associated with decreased asthma exacerbations in adolescents and young adults

RATIONALE

Metformin is a commonly used antidiabetes medication with suggested anti-inflammatory and antioxidative effects. Metformin use has been associated with lower risk of asthma exacerbations and hospitalizations in adults. Here, we aimed to evaluate how asthma exacerbation rates changed after adolescents and young adults were prescribed metformin, and to learn if those changes were related to metformin prescription adherence.

METHODS

Using secondary data of patients between 12 and 20 years old with asthma diagnosis and a metformin prescription from the Arkansas All Payers Claim Database and Arkansas School body mass index (BMI) database, we estimated the change in annualized asthma exacerbation rates after metformin prescription. We also evaluated the association of prescription adherence to the changes in those rates using univariate and multivariate regression models.

RESULTS

A total of 464 patients met inclusion criteria. Outpatient exacerbation rates decreased after metformin prescription (13.4% only before vs. 7.8% only after, p = .009), and the annualized rate decreased more after metformin prescription as adherence increased (rank r = -.165, p < .001). After adjusting for potential confounders-age, sex, BMI, and inhaled corticoid steroid use-the strength of the association was attenuated.

CONCLUSIONS

Asthma exacerbation rates decreased after metformin prescription, but a larger sample of patients who have experienced exacerbations and including patients with asthma who have not been prescribed metformin is needed to better know whether these decreases are driven by metformin use.

Hyperglycaemia and Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) may coexist with type 2 diabetes mellitus (T2DM). Patients with COPD have an increased risk of developing T2DM compared with a control but, on the other side, hyperglycaemia and DM have been associated with reduced predicted levels of lung function. The mechanistic relationships between these two diseases are complicated, multifaceted, and little understood, yet they can impact treatment strategy. The potential risks and benefits for patients with T2DM treated with pulmonary drugs and the potential pulmonary risks and benefits for patients with COPD when taking antidiabetic drugs should always be considered. The interaction between the presence and/or treatment of COPD, risk of infection, presence and/or treatment of T2DM and risk of acute exacerbations of COPD (AECOPDs) can be represented as a vicious circle; however, several strategies may help to break this circle. The most effective approach to simultaneously treating T2DM and COPD is to interfere with the shared inflammatory substrate, thus targeting both lung inflammation (COPD) and vascular inflammation (DM). In any case, it is always crucial to establish glycaemic management since the reduction in lung function found in people with diabetes might decrease the threshold for clinical manifestations of COPD. In this article, we examine possible connections between COPD and T2DM as well as pharmacological strategies that could focus on these connections.

Senotherapy for lung diseases

Increasing evidence suggests that there is acceleration of lung ageing in chronic lung diseases, such as chronic obstructive pulmonary disease (COPD) and idiopathic pulmonary fibrosis (IPF), with the accumulation of senescent cells in the lung. Senescent cells fail to repair tissue damage and release an array of inflammatory proteins, known as the senescence-associated secretory phenotype, which drive further senescence and disease progression. This suggests that targeting cellular senescence with senotherapies may treat the underlying disease process in COPD and IPF and thus reduce disease progression and mortality. Several existing or future drugs may inhibit the development of cellular senescence which is driven by chronic oxidative stress (senostatics), including inhibitors of PI3K-mTOR signalling pathways, antagomirs of critical microRNAs and novel antioxidants. Other drugs (senolytics) selectively remove senescent cells by promoting apoptosis. Clinical studies with senotherapies are already underway in chronic lung diseases.

Metformin Use Is Associated With Lower Mortality in Veterans With Diabetes Hospitalized With Pneumonia

BACKGROUND

Recent studies suggest that metformin use may be associated with improved infectious disease-related outcomes, whereas other papers suggest potentially worse outcomes in serious bacterial infections. Our purpose was to examine the association of prior outpatient prescription of metformin on 30- and 90-day mortality for older veterans with pre-existing diabetes hospitalized with pneumonia.

METHODS

We conducted a retrospective cohort study using national Department of Veterans Affairs data of patients ≥65 years with a prior history of diabetes who were hospitalized with pneumonia over a 10-year period (fiscal years 2002-2012.) For our primary analysis, we created a propensity score and matched metformin users to nonusers 1:1.

RESULTS

We identified 34 759 patients who met the inclusion criteria, 20.3% of whom were prescribed metformin. Unadjusted 30-day mortality was 9.6% for those who received metformin versus 13.9% in nonusers (P < .003), and 90-day mortality was 15.8% for those who received metformin versus 23.0% for nonusers (P < .0001). For the propensity score model, we matched 6899 metformin users to 6899 nonusers. After propensity matching, both 30-day (relative risk [RR]: .86; 95% confidence interval [CI]: .78-.95) and 90-day (RR: .85; 95% CI: .79-.92) mortality was significantly lower for metformin users.

CONCLUSIONS

Prior receipt of metformin was associated with significantly lower mortality after adjusting for potential confounders. Additional research is needed to examine the safety and potential benefits of metformin use in patients with respiratory infections.

Analysis of risk factors for COVID-19-related fatal outcome in 337991 patients with type 1 and type 2 diabetes mellitus in 2020–2022 years: Russian nationwide retrospective study

BACKGROUND: The coronavirus pandemic has had an extremely negative impact on the patients with diabetes mellitus (DM both in terms of a more severe course of COVID -19 and an increased risk of death.

AIM: Analysis of risk factors for death due to COVID -19 in patients with DM type 1 and type 2 (DM1 and DM2).

MATERIALS AND METHODS: Retrospective analysis of the database of the national diabetes register (NDR), which included DM patients with COVID-19 and reported virus infection outcome (recovery/or death) in 15 712 DM1 and 322 279 DM2 patients during a 2-year follow-up period (01/02/2020 to 03/04/2022) (discharge date)).

RESULTS: Case fatality rate in patients with DM, who underwent COVID -19 was 17.1% (DM1–8.8%; DM2–17.5%). As a result of multivariate regression analysis of seven significant factors in DM1 and thirteen in DM2 (evaluated by univariate anlisys), a number of the most important predictors of risk for fatal outcome were identified: in DM1 these were age ≥65 years (OR =4.01, 95% CI: 1.42–11.36), presence of arterial hypertension (AH) (OR =2.72, 95% CI: 1.03 -7.16) and diabetic foot syndrome (DFS) (OR = 7.22, 95% CI: 1.98–26.29); for T2DM: age ≥ 65 years (OR =2.53, 95% CI: 1.96–3.27), male (OR =1.51, 95% CI: 1.23–1.84), duration DM ≥10 years (OR =2.01, 95% CI: 1.61–2.51), BMI ≥ 30 kg/m2 (OR =1.26, 95% CI: 1.02–1.55), ASCVD/CKD (OR =1.49, 95% CI: 1.01–2.04), history of diabetic coma (OR =12.97, 95% CI: 1.89–88.99) and presence of disability ( OR =1.40, 95% CI: 1.14–1.73). In T2DM, the type of antidiabetic therapy (ADT) prior to COVID -19 (last visit before the development of infection) had a significant impact: Insulin therapy (OR = 1.64, 95% CI: 1.30–2.07), sulfonylureas (SU) (OR =1.51, 95% CI: 1.23–1.84)); dipeptidyl peptidase-4 inhibitor (iDPP-4) therapy (OR =0.57, 95% CI: 0.39–0.83) and sodium-glucose cotransporter-2 inhibitor (iSGLT2) therapy (OR =0.64, 95% CI: 0.46–0.88). Vaccination was the most important protective factor in both types of DM: DM1 OR =0.19, 95% CI: 0.06–0.59; SD2 OR =0.20, 95% CI: 0.16–0.26.

CONCLUSION: The common risk factor for fatal outcome in both DM1 and DM2 was age ≥65 years; in DM1 — history of hypertension and DFS, in DM2 — male sex, diabetes duration ≥10 years, BMI ≥30 kg/m2, history of ASCVD/CKD and diabetic coma, disability. In T2DM, significant differences in risk were observed depending on the type of ADT: insulin and SU therapy were factors that increased the risk of death, whereas therapy with iDPP-4 and iSGLT2 reduced the risk of death. Vaccination reduced the risk of death in DM1 and DM2 by 5.2 and 5-fold, respectively.

Effects of Metformin, Insulin on Hematological Parameters of COVID-19 Patients with Type 2 Diabetes

Background

COVID-19 infection caused by SARS-COV-2 can result in multi-organ injuries and significant mortality in severe and critical patients, particularly those with type 2 diabetes as a comorbidity. Metformin and insulin are the main diabetes medications that affect the outcome of patients with COVID-19.

Objective

The purpose of our study was to find out the features of the hematological indicators of patients with COVID-19 patients and type 2 diabetes.

Methods

This is a retrospective study of the hospital confirmed COVID-19 patients between January to March 2022, who were admitted to Transcarpathian Regional Clinical Infectious Diseases Hospital (Uzhhorod, Ukraine).

Results

The effect of type 2 diabetes, metformin, and insulin on COVID-19 were analyzed, respectively. Demographics and blood laboratory indices were collected. In patients who took metformin, the level of CRP was significantly lower than in patients who did not take metformin (24 mg/L [IQR 15 - 58] vs 52 mg/L, [IQR 22-121], P = 0.046).

Conclusion

Our findings suggest that pre-admission metformin use may benefit COVID-19 patients with type 2 diabetes.

Comorbidities in childhood-onset and adult-onset asthma

BACKGROUND

Age of asthma onset has emerged as an important determinant of asthma phenotypes; however, the comorbidities that predominate in either childhood- or adult-onset asthma are not known.

OBJECTIVE

To identify comorbidities associated with adult-onset asthma vs childhood-onset asthma and with age of asthma diagnosis.

METHODS

We analyzed data on 27,437 adult participants in the National Health and Nutrition Examination Surveys conducted from 2001 to 2018. Logistic regression adjusted for covariates was used to identify comorbidities associated with the asthma phenotypes and age of asthma diagnosis.

RESULTS

Approximately 12.6% of participants were ever diagnosed with asthma; the prevalence of childhood-onset (before 18 years old) and adult-onset (≥ 18 years old) current asthma was 2.7% and 5.5%, respectively. After adjustment for covariates including age, adult-onset asthma was associated with higher odds of obesity (odds ratio [OR], 1.46; 95% confidence interval [CI], 1.09-1.96), hypercholesterolemia (OR, 1.67; 95% CI, 1.08-2.56), borderline high serum triglycerides (OR, 1.78; 95% CI, 1.17-2.71), and osteoarthritis (OR, 1.52; 95% CI, 1.04-2.20) than was childhood-onset asthma. Older age of asthma diagnosis (per 5-year increase) was also associated with higher odds of diabetes (OR, 1.04; 95% CI, 1.00-1.07) and hypertension (OR, 1.05; 95% CI, 1.02-1.07), whereas younger age of asthma diagnosis was associated with higher odds of chronic obstructive pulmonary disease (OR, 1.12; 95% CI, 1.04-1.19).

CONCLUSION

Age- and covariates-adjusted prevalence of obesity, dyslipidemia, arthritis, diabetes, and hypertension is higher in adult-onset asthma than in childhood-onset asthma, and with older age of asthma diagnosis. Conversely, the prevalence of chronic obstructive pulmonary disease increases with younger age of asthma diagnosis.

Cardiovascular outcomes of metformin use in patients with type 2 diabetes and chronic obstructive pulmonary disease

Aim: To know whether metformin use has different influence on cardiovascular risks in patients with type 2 diabetes mellitus (T2DM) and chronic obstructive pulmonary disease (COPD) as compared with metformin no-use.

Methods: This study employed a retrospective cohort study design. Using propensity score matching, we recruited 55 ,224 pairs of metformin users and nonusers from Taiwan’s National Health Insurance Research Database between 1 January 2000, and 31 December 2017. Cox proportional-hazards models with robust standard error estimates were used to compare the risks of cardiovascular outcomes.

Results: The mean study period of metformin users and nonusers was 11.04 (5.46) and 12.30 (4.85) years, respectively. Compared with the nonuse of metformin, the adjusted hazard ratios (95% CI) of metformin use for composited cardiovascular events, stroke, coronary artery disease, and heart failure were 0.51 (0.48–0.53), 0.62 (0.59–0.64), 0.48 (0.46–0.50), and 0.61 (0.57–0.65), respectively. The longer cumulative duration of metformin use had even lower adjusted hazard ratios compared with metformin nonuse.

Conclusion: In patients with coexisting T2DM and COPD, metformin use was associated with significantly lower risks of CVD; moreover, longer duration of metformin use was associated with a lower risk of CVD. A well-designed prospective study is required to verify the results.

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.

Renin-angiotensin system antagonists and mortality due to pneumonia, influenza, and chronic lower respiratory disease in patients with hypertension

BACKGROUND

It is controversial whether angiotensin-converting enzyme inhibitors or angiotensin receptor blockers (ACEI/ARB) have a potentially beneficial role in the respiratory system. This study investigated the association between ACEI/ARB medications and respiratory-related mortality in hypertensive patients in a real-world nationally representative cohort.

METHODS

This was a retrospective analysis based on a prospective cohort study. A total of 10,530 patients with hypertension aged ≥ 20 years were included. The data was extracted from the US National Health and Nutrition Examination Survey during 1988-1994 and 1999-2006. The study was approved by the Institutional Review Boards. Moreover, inform concent was taken form all the participants.

RESULTS

Overall, 27.7% (n = 2920) patients took ACEI/ARB agents. During a median follow-up of 12.4 years, 278 individuals died of respiratory disease, including chronic lower respiratory disease (n = 155) and influenza or pneumonia (n = 123). Compared with the patients without ACEI/ARB use, those taking ACEI/ARB were not associated with respiratory-specific mortality in a multivariable-adjusted Cox model. After 1: 1 matching, taking ACEI/ARB was also not related to respiratory mortality (Hazard ratio (HR) = 1.07, 95% CI: 0.79-1.43), influenza- or pneumonia-related (HR = 1.00, 95% CI: 0.65-1.54) and chronic pulmonary mortality (HR = 1.13, 95% CI: 0.75-1.69). After separating ACEI and ARB from anti-hypertensive medications, those associations remained unchanged.

CONCLUSIONS

We discovered no significant link between ACEI or ARB medication and pulmonary-related mortality in hypertensive patients. In hypertensive patients, standard ACEI/ARB administration may have little effect on the respiratory system.

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.

Preadmission usage of metformin and mortality in COVID-19 patients including the post-discharge period

BACKGROUND

The effect of preadmission metformin usage (PMU) on the mortality of coronavirus disease-2019 (COVID-19) patients with diabetes is conflicting. Most studies have focused on in-hospital mortality; however, mortality after discharge also increases in COVID-19 patients.

AIMS

Examining the effect of PMU on all-cause mortality, including the post-discharge period.

METHODS

Patients with diabetes who were hospitalised in 2020 due to COVID-19 were included in the study. They were divided into two groups: those with a history of metformin use (MF( +)) and those without such history (MF( -)). Propensity score matching (PSM) was performed at a ratio of 1:1 for age and sex. COX regression analyses were used to demonstrate risk factors for mortality.

RESULTS

We investigated 4103 patients hospitalised for COVID-19. After excluding those without diabetes or with chronic liver/kidney disease, we included the remaining 586 patients, constituting 293 women (50%) with an overall mean age of 66 ± 11.9 years. After PSM analysis, the in-hospital and post-discharge mortality rates were higher in the MF( -) group though not significantly different. However, overall mortality was higher in the MF( -) group (51 (42.5%) vs. 35 (29.2%), p = 0.031). For overall mortality, the adjusted HR was 0.585 (95% CI: 0.371 - 0.920, p = 0.020) in the MF( +) group.

CONCLUSION

PMU is associated with reducing all-cause mortality. This effect starts from the in-hospital period and becomes more significant with the post-discharge period. The main limitations were the inability to evaluate the compliance with metformin and the effects of other medications due to retrospective nature.

Does metformin affect outcomes in COVID-19 patients with new or pre-existing diabetes mellitus? A systematic review and meta-analysis

Aims

The COVID‐19 pandemic is a global public health emergency and patients with diabetes mellitus (DM) are disproportionately affected, exhibiting more severe outcomes. Recent studies have shown that metformin is associated with improved outcomes in patients with COVID‐19 and DM and may be a potential candidate for drug repurposing. We aimed to investigate the effects of metformin on outcomes in patients with COVID‐19 and DM.

Methods

Databases (PubMed, Scopus, Web of Science, EMBASE, Clinicaltrials.gov and Cochrane library) were searched up to 10 April 2021 for studies reporting data on metformin use in COVID‐19 patients with DM. The risk of bias was assessed using the Newcastle–Ottawa scale. Certainty of evidence was rated using the GRADE approach. The primary outcome was mortality reported as odds ratio (OR). A random‐effects meta‐analysis was carried out on both unadjusted and adjusted ORs. This study is registered with PROSPERO, CRD42020221842.

Results

In total, 2 916 231 patients from 32 cohort studies were included in the quantitative and qualitative synthesis. The meta‐analysis showed that metformin was significantly associated with lower mortality in COVID‐19 patients with DM in both unadjusted (OR 0.61 [95% confidence interval: 0.53–0.71], P < .00001, I² = 70%) and adjusted (OR 0.78 [95% confidence interval: 0.69–0.88], P < .00001, I² = 67%) models.

Conclusion

Poor outcomes in COVID‐19 patients with DM can be attributed to inadequate glycaemic control and weakened immune responses. Metformin has multiple effects that can improve outcomes in patients with DM and our findings highlight a possible role of its use. However, robust randomised trials are needed to thoroughly assess its use.

Reduced decline of lung diffusing capacity in COPD patients with diabetes and metformin treatment

We studied whether in patients with COPD the use of metformin for diabetes treatment was linked to a pattern of lung function decline consistent with the hypothesis of anti-aging effects of metformin. Patients of GOLD grades 1–4 of the COSYCONET cohort with follow-up data of up to 4.5 y were included. The annual decline in lung function (FEV₁, FVC) and CO diffusing capacity (KCO, TLCO) in %predicted at baseline was evaluated for associations with age, sex, BMI, pack-years, smoking status, baseline lung function, exacerbation risk, respiratory symptoms, cardiac disease, as well as metformin-containing therapy compared to patients without diabetes and metformin. Among 2741 patients, 1541 (mean age 64.4 y, 601 female) fulfilled the inclusion criteria. In the group with metformin treatment vs. non-diabetes the mean annual decline in KCO and TLCO was significantly lower (0.2 vs 2.3, 0.8 vs. 2.8%predicted, respectively; p < 0.05 each), but not the decline of FEV₁ and FVC. These results were confirmed using multiple regression and propensity score analyses. Our findings demonstrate an association between the annual decline of lung diffusing capacity and the intake of metformin in patients with COPD consistent with the hypothesis of anti-aging effects of metformin as reflected in a surrogate marker of emphysema.

Thiazolidinedione Use in Individuals With Type 2 Diabetes and Chronic Obstructive Pulmonary Disease

Few studies have investigated the effects of various antidiabetic agents on individuals with both type 2 diabetes mellitus (T2DM) and Chronic obstructive pulmonary disease (COPD). This study compared mortality, cardiovascular events and respiratory outcomes in individuals with both T2DM and COPD taking TZD vs. those not taking TZD. From Taiwan's National Health Insurance Research Database, 12 856 propensity-score-matched TZD users and non-users were selected between January 1, 2000, and December 31, 2012. Cox proportional hazards models were used to calculate the risks of investigated outcomes. Compared with non-use of TZD, the adjusted hazard ratios (95% CI) of TZD use were stroke 1.63 (1.21–2.18), coronary artery disease 1.55 (1.15–2.10), heart failure 1.61 (1.06–2.46), non-invasive positive pressure ventilation 1.82 (1.46–2.27), invasive mechanical ventilation 1.23 (1.09–1.37), bacterial pneumonia 1.55 (1.42–1.70), and lung cancer 1.71 (1.32–2.22), respectively. The stratified analysis disclosed that rosiglitazone, not pioglitazone, was associated with significantly higher risk of major cardiovascular events than TZD non-users. In patients with concomitant T2DM and COPD, TZD use was associated with higher risks of cardiovascular events, ventilation use, pneumonia, and lung cancer. Use of TZD in these patients should be supported by monitoring for cardiovascular and respiratory complications.

Mechanisms and Potential Roles of Glucose-Lowering Agents in COVID-19: A Review

OBJECTIVE

To explore mechanistic benefits of glucose-lowering agents that extend beyond glycemic control with the potential to mitigate coronavirus disease 2019 (COVID-19) complications.

DATA SOURCES

The following PubMed literature search terms were used from July 2020 to January 2, 2021: diabetes, COVID-19, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), glucose-lowering agents, and pharmacology.

STUDY SELECTION AND DATA EXTRACTION

English-language studies reporting on the association between diabetes, COVID-19 adverse outcomes, and the potential roles of glucose-lowering agents were reviewed.

DATA SYNTHESIS

Selected glucose-lowering agents have benefits beyond glycemic control, with the potential to reduce the risks of severe complications during SARS-CoV-2 infection. Key benefits include anti-inflammatory, anticoagulant, immune modulating, and enzyme/receptor effects.

RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE

This review summarizes the current knowledge of glucose-lowering agents and their potential roles in COVID-19 outcomes. Considering beneficial mechanisms on COVID-19 outcomes that extend beyond glycemic control as well as safety profiles, current data suggest that dipeptidyl peptidase-IV (DPP-IV) inhibitors and metformin may have the most promise and warrant further investigation.

CONCLUSIONS

Certain glucose-lowering agents may offer additional benefits beyond glucose control-namely, by modulating the mechanisms contributing to adverse outcomes related to COVID-19 in patients with diabetes. DPP-IV inhibitors and metformin appear to have the most promise. However, current published literature on diabetes medications and COVID-19 should be interpreted with caution. Most published studies are retrospective and consist of convenience samples, and some lack adequate analytical approaches with confounding biases. Ongoing trials aim to evaluate the effects of glucose-lowering agents in reducing the severity of COVID-19 outcomes.

Susceptibility for Some Infectious Diseases in Patients With Diabetes: The Key Role of Glycemia

Uncontrolled diabetes results in several metabolic alterations including hyperglycemia. Indeed, several preclinical and clinical studies have suggested that this condition may induce susceptibility and the development of more aggressive infectious diseases, especially those caused by some bacteria (including Chlamydophila pneumoniae, Haemophilus influenzae, and Streptococcus pneumoniae, among others) and viruses [such as coronavirus 2 (CoV2), Influenza A virus, Hepatitis B, etc.]. Although the precise mechanisms that link glycemia to the exacerbated infections remain elusive, hyperglycemia is known to induce a wide array of changes in the immune system activity, including alterations in: (i) the microenvironment of immune cells (e.g., pH, blood viscosity and other biochemical parameters); (ii) the supply of energy to infectious bacteria; (iii) the inflammatory response; and (iv) oxidative stress as a result of bacterial proliferative metabolism. Consistent with this evidence, some bacterial infections are typical (and/or have a worse prognosis) in patients with hypercaloric diets and a stressful lifestyle (conditions that promote hyperglycemic episodes). On this basis, the present review is particularly focused on: (i) the role of diabetes in the development of some bacterial and viral infections by analyzing preclinical and clinical findings; (ii) discussing the possible mechanisms by which hyperglycemia may increase the susceptibility for developing infections; and (iii) further understanding the impact of hyperglycemia on the immune system.

Metabolic Syndrome “Interacts” With COVID-19

COVID-19, caused by the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), has emerged as a global pandemic and poses a great threat to public health and society in general. SARS-CoV-2 invades cells via its spike protein, which initiates endocytosis via its binding to host receptor angiotensin-converting enzyme 2 (ACE2) and membrane fusion after being cleaved by the serine protease, TMPRSS2. The most common clinical manifestations are fever, dry cough, fatigue and abnormalities on chest computed tomography (CT). However, some patients rapidly progress to severe pneumonia and develop acute respiratory distress syndrome (ARDS). Furthermore, SARS-CoV-2 triggers a severe cytokine storm, which may explain the deterioration of pre-existing metabolic disorders. Interestingly, conversely, underlying metabolic-related diseases, including hypertension, diabetes, cardiovascular disease, etc., are associated with progression and poor prognosis of COVID-19. The putative mechanisms are dysregulation of ACE2, impaired immunity especially uncontrolled hyperinflammation, hypercoagulability, etc. In this review, we summarize the crosstalk between COVID-19 and metabolic diseases and propose that in addition to controlling COVID-19, more intensive attention should be paid to the symptomatic treatment and prevention of pre-existing and foreseeable metabolic comorbidities.Significance statement: Coronavirus disease 2019 (COVID-19) has rapidly spread worldwide and has exerted a great influence on public health and society, urging scientists to find efficient therapeutics. Metabolic disturbance involving various organs has been found in these patients, including diabetes, fatty liver, acute kidney injury (AKI), etc. In turn, these preexisting metabolic syndromes could exacerbate COVID-19. In this review, we focus on the close interaction between COVID-19 and metabolic syndrome, as well as the potential of repurposing metabolic-related drugs and the importance of treating metabolic diseases in COVID-19 patients.

Considerations for Gut Microbiota and Probiotics in Patients with Diabetes Amidst the Covid-19 Pandemic: A Narrative Review

Objective: To review data implicating microbiota influences on Coronavirus Disease 2019 (COVID-19) in patients with diabetes.

Methods: Primary literature review included topics: “COVID-19,” “SARS,” “MERS,” “gut micro-biota,” “probiotics,” “immune system,” “ACE2,” and “metformin.”

Results: Diabetes was prevalent (~11%) among COVID-19 patients and associated with increased mortality (about 3-fold) compared to patients without diabetes. COVID-19 could be associated with worsening diabetes control and new diabetes diagnosis that could be linked to high expression of angiotensin-converting enzyme 2 (ACE2) receptors (coronavirus point of entry into the host) in the endocrine pancreas. A pre-existing gut microbiota imbalance (dysbiosis) could contribute to COVID-19–related complications in patients with diabetes. The COVID-19 virus was found in fecal samples (~55%), persisted for about 5 weeks, and could be associated with diarrhea, suggesting a role for gut dysbiosis. ACE2 expressed on enterocytes and colonocytes could serve as an alternative route for acquiring COVID-19. Experimental models proposed some probiotics, including Lactobacillus casei, L. plantarum, and L. salivarius, as vectors for delivering or enhancing efficacy of anti-coronavirus vaccines. These Lactobacillus probiotics were also beneficial for diabetes. The potential mechanisms for interconnections between coronavirus, diabetes, and gut microbiota could be related to the immune system, ACE2 pathway, and metformin treatment. There were suggestions but no proof supporting probiotics benefits for COVID-19 infection.

Conclusion: The data suggested that the host environment including the gut microbiota could play a role for COVID-19 in patients with diabetes. It is a challenge to the scientific community to investigate the beneficial potential of the gut microbiota for strengthening host defense against coronavirus in patients with diabetes.

The Efficacy and Potential Mechanisms of Metformin in the Treatment of COVID-19 in the Diabetics: A Systematic Review

INTRODUCTION

Diabetes mellitus (DM) is one of the most common comorbidities among patients with coronavirus disease 2019 (COVID-19) which may exacerbate complications of this new viral infection. Metformin is an anti-hyperglycemic agent with host-directed immune-modulatory effects, which relieve exaggerated inflammation and reduce lung tissue damage. The current systematic review aimed to summarize the available evidence on the potential mechanism of action and the efficacy of metformin in COVID-19 patients with DM.

METHODS

A systematic search was carried out in PubMed/Medline, EMBASE, the Cochrane Controlled Register of Trials (CENTRAL), and Web of Science up to July 30, 2020. The following keywords were used: "COVID-19", "SARS-CoV-2", "2019-nCoV", "metformin", and "antidiabetic drug".

RESULTS

Fourteen studies were included in our systematic review. Three of them were observational with 6,659 participants. Decreasing insulin resistance, reduction of some inflammatory cytokines like IL-6 and TNF-α, modulation of angiotensin-converting enzyme 2 (ACE2) receptor, and improving neutrophil to lymphocyte ratio are some of the potential mechanisms of metformin in COVID-19 patients with DM. Nine out of fourteen articles revealed the positive effect of metformin on the prognosis of COVID-19 in diabetic or even non-diabetic patients. Moreover, different studies have shown that metformin is more effective in women than men.

CONCLUSIONS

The use of metformin may lead to improve the clinical outcomes of patients with mild to moderate SARS-CoV-2, especially in diabetic women. Further observational studies should be conducted to clarify the effects of metformin as a part of the treatment strategy of COVID-19.

Cardiometabolic vigilance in COVID-19 and resource husbandry in resource-challenged times: Clinical practice- based expert opinion

BACKGROUND AND AIMS

The ongoing pandemic of coronavirus disease 2019 (COVID-19) is rapidly evolving, thereby posing a profound challenge to the global healthcare system. Cardiometabolic disorders are associated with poor clinical outcomes in persons with COVID-19. Healthcare challenges during the COVID-19 pandemic are linked to resource constraints including shortage of Personal Protective Equipment's (PPE), laboratory tests and medication. In this context, a group of clinical experts discussed the endocrine and cardiology vigilance required in times of COVID-19. Further, the group proposed certain resource husbandry recommendations to be followed during the pandemic to overcome the constraints.

METHOD

The clinical experts discussed and provided their inputs virtually. The expert panel included clinical experts comprising endocrinologists, Consultant Physicians and cardiologists from India. The panel thoroughly reviewed existing literature on the subject and proposed expert opinion.

RESULTS

The expert panel put forward clinical practice-based opinion for the management of cardiometabolic conditions including diabetes mellitus and hypertension. As these conditions are associated with poor clinical outcomes, the expert panel recommends that these persons be extra-cautious and take necessary precautions during the ongoing pandemic. Further, experts also provided appropriate, affordable, available and accessible solution to the resource constraint situations in times of COVID-19 pandemic.

CONCLUSION

The clinical expert opinion put forward in this article will serve as a reference for clinicians treating diabetes and cardiovascular disease during the COVID-19 pandemic.

Is there an association between metformin use and clinical outcomes in diabetes patients with COVID-19?

Aim

Previous studies have reported inconsistent results regarding the association between metformin use and clinical outcomes in diabetes mellitus (DM) patients with coronavirus disease 2019 (COVID-19). This study aimed to evaluate the association between metformin use and clinical outcomes in DM patients with COVID-19.

Methods

This retrospective study was based on claims data. All diseases, including COVID-19, were defined using International Classification of Diseases 10th Revision (ICD-10) codes. Patients were divided into three groups depending on metformin use: CON (those not taking DM medication); N-MFOM (those taking DM medications other than metformin); and MFOM (those taking metformin for DM). Ultimately, 1865 patients were included; CON, N-MFOM and MFOM groups comprised 1301, 95 and 469 patients, respectively.

Results

Kaplan–Meier analyses showed that MFOM patients had poorer survival rates than those in the CON group, but there were no significant differences in survival rates between MFOM and N-MFOM groups. Multivariate Cox regression analyses revealed more favourable survival in CON than in N-MFOM patients, but there was no statistically significant difference in MFOM vs the other groups. Also, there were no significant differences in rates of use of inotropes, extracorporeal membrane oxygenation, conventional oxygen therapy, high-flow nasal cannulas or mechanical ventilators, nor in the rates of acute kidney injury or cardiac events across all study groups.

Conclusion

No definite association could be found between metformin use and clinical outcomes, including survival. However, given the disproportionate participant numbers in our groups and small number of events, further studies are needed to determine whether the use of metformin has favourable or unfavourable effects in DM patients with COVID-19.

Metformin and COVID-19: From cellular mechanisms to reduced mortality

Type 2 diabetes mellitus (T2DM) is associated with both poorer clinical outcomes during the COVID-19 pandemic and an increased risk of death in such hospitalized patients. While the role of glucose control has been emphasized to improve the prognosis, the impact of different glucose-lowering agents remains largely unknown. Metformin remains the first-line pharmacological choice for the management of hyperglycaemia in T2DM. Because metformin exerts various effects beyond its glucose-lowering action, among which are anti-inflammatory effects, it may be speculated that this biguanide might positively influence the prognosis of patients with T2DM hospitalized for COVID-19. The present concise review summarizes the available data from observational retrospective studies that have shown a reduction in mortality in metformin users compared with non-users, and briefly discusses the potential underlying mechanisms that might perhaps explain this favourable impact. However, given the potential confounders inherently found in observational studies, caution is required before drawing any firm conclusions in the absence of randomized controlled trials.

Clinical Impact Potential of Supplemental Nutrients as Adjuncts of Therapy in High-Risk COVID-19 for Obese Patients

The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) disease (COVID-19) in China at the end of 2019 caused a major global pandemic and continues to be an unresolved global health crisis. The supportive care interventions for reducing the severity of symptoms along with participation in clinical trials of investigational treatments are the mainstay of COVID-19 management because there is no effective standard therapy for COVID-19. The comorbidity of COVID-19 rises in obese patients. Micronutrients may boost the host immunity against viral infections, including COVID-19. In this review, we discuss the clinical impact potential of supplemental nutrients as adjuncts of therapy in high-risk COVID-19 for obese patients.

Coronavirus disease 2019 (COVID-19) and obesity. Impact of obesity and its main comorbidities in the evolution of the disease

The COVID-19 pandemic is posing a great challenge worldwide. Its rapid progression has caused thousands of deaths worldwide. Although multiple aspects remain to be clarified, some risk factors associated with a worse prognosis have been identified. These include obesity and some of its main complications, such as diabetes and high blood pressure. Furthermore, although the possible long-term complications and psychological effects that may appear in survivors of COVID-19 are not well known yet, there is a concern that those complications may be greater in obese patients. In this manuscript, we review some of the data published so far and the main points that remain to be elucidated are emphasized.

Association of Metformin Use with Asthma Exacerbation in Patients with Concurrent Asthma and Diabetes: A Systematic Review and Meta-Analysis of Observational Studies

Background

Asthma and diabetes are both diseases that affect a wide range of people worldwide. As a common treatment for diabetes, metformin has also been reported to be effective in improving asthma outcomes. We conducted a combined analysis to examine the efficacy of metformin in reducing asthma exacerbation in patients with concurrent asthma and diabetes.

Methods

We searched the PubMed, Embase, and CENTRAL databases for articles published prior to April 2020 to find observational studies of individuals with concurrent asthma and diabetes that compared the risk of asthma exacerbation between metformin users and nonusers. Two researchers separately screened the studies, extracted data, and evaluated the risk of bias. The primary outcome was the adjusted risk of asthma exacerbation. The secondary outcomes were the adjusted risk of asthma-related hospitalization and emergency room visits. Review Manager was used for data analysis and plotting. I² and χ² tests were used to estimate heterogeneity. A random effects or fixed effects model was used depending on the heterogeneity. Odds ratios were calculated for dichotomous variables.

Results

We included two studies with a total of 25252 patients. The pooled effect size showed that metformin was inversely associated with a risk of asthma exacerbation (OR = 0.65, 95% CI 0.28–1.48; χ² = 5.42, P=0.02; I² = 82%), asthma-related emergency department visits (OR = 0.81, 95% CI 0.74–0.89; χ² = 0.36, P=0.55; I² = 0%), and hospitalizations (OR = 0.43, 95% CI 0.14–1.29; χ² = 4.01, P=0.05; I² = 75%).

Conclusion

This meta-analysis suggested that metformin decreased the risk of asthma-related emergency room visits for patients with concurrent asthma and diabetes. Metformin reduced the risk of asthma-related hospitalization and exacerbation but was not statistically significant. More randomized trials involving larger samples should be considered, and the mechanisms of these effects need to be fully elucidated.

[Diabetes and COVID-19: analysis of the clinical outcomes according to the data of the russian diabetes registry]

BACKGROUND

Data on the national level and worldwide show a higher rate of mortality in patients with diabetes mellitus (DM) due to COVID-19, which determines the high relevance of risk factor analysis for outcomes in DM patients to substantiate the strategy for this category of patients.

AIM

To assess the effect of clinical and demographic parameters (age, gender, body mass index (BMI), glycemic control (HbA1c), and antidiabetic and antihypertensive drugs, including ACE inhibitors and ARBs) on clinical outcomes (recovery or death) in patients with type 2 DM.

MATERIALS AND METHODS

A retrospective analysis of the Russian Register of Diabetes database was performed, including patients with type 2 DM (n=309) who suffered pneumonia/COVID-19 in the period from 01.02.2020 to 27.04.2020 and the indicated outcome of the disease (recovery or death) RESULTS: The percentage of lethality was determined to be 15.2% (47 of 309 people). The degree of lethality was found to be significantly higher in males (OR=2.08; 95% CI 1.1&ndash;3.9; p=0.022) and in patients on insulin therapy (OR=2.67; 95% CI; 1.42&ndash;5.02; p=0.002), while it was significantly lower in patients with an age &lt;65 years (OR=0.34; 95% CI 0.18&ndash;0.67; p=0.001) and in patients receiving metformin (OR=0.26; 95% CI 0.14&ndash;0,5; p&lt;0.0001), antihypertensive therapy (OR=0.43; 95% CI 0.22&ndash;0.82; p=0.009), &beta;-blockers (OR=0.26; 95% CI 0.08&ndash;0.86; p=0.018), diuretics (OR=0.4; 95% CI 0.17&ndash;0.93; p=0.028) and renin-angiotensin system blockers (ACE inhibitors or ARBs) (OR=0.36; 95% CI 0.18&ndash;0.74; p=0.004). A tendency to an increase in lethality at higher rates of HbA1c and BMI was present, but it did not reach a statistical significance. Differences between patients receiving insulin therapy and those who were not receiving the insulin therapy were observed as follows: a significantly longer duration of type 2 DM (13.4 vs. 6.8 years, respectively; p&lt;0.0001), worse overall glyacemic control (HbA1c: 8.1% vs. 7.0%, resp.; p&lt;0.0001), and three times more frequent failure to achieve the HbA1c goal by more than 2.5% (14.7% vs. 5.9%, resp.; p=0.04).

CONCLUSION

The identified risk factors for lethality in patients with type 2 DM indicate that good glycemic control and previous treatment with metformin and antihypertensive drugs (including RAS blockers) could reduce the frequency of deaths. In patients on insulin therapy, a higher lethality degree was associated with worse glycemic control.

Diabetes in COVID-19: Prevalence, pathophysiology, prognosis and practical considerations

BACKGROUND AND AIMS

High prevalence of diabetes makes it an important comorbidity in patients with COVID-19. We sought to review and analyze the data regarding the association between diabetes and COVID-19, pathophysiology of the disease in diabetes and management of patients with diabetes who develop COVID-19 infection.

METHODS

PubMed database and Google Scholar were searched using the key terms 'COVID-19', 'SARS-CoV-2', 'diabetes', 'antidiabetic therapy' up to April 2, 2020. Full texts of the retrieved articles were accessed.

RESULTS

There is evidence of increased incidence and severity of COVID-19 in patients with diabetes. COVID-19 could have effect on the pathophysiology of diabetes. Blood glucose control is important not only for patients who are infected with COVID-19, but also for those without the disease. Innovations like telemedicine are useful to treat patients with diabetes in today's times.

The Role of Adipocytes and Adipocyte-Like Cells in the Severity of COVID-19 Infections

Coronavirus disease-2019 (COVID-19), caused by the highly pathogenic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), demonstrates high morbidity and mortality caused by development of a severe acute respiratory syndrome connected with extensive pulmonary fibrosis. In this Perspective, we argue that adipocytes and adipocyte-like cells, such as pulmonary lipofibroblasts, may play an important role in the pathogenic response to SARS-CoV-2. Expression of angiotensin-converting enzyme 2 (the functional receptor for SARS-CoV) is upregulated in adipocytes of patients with obesity and diabetes, which turns adipose tissue into a potential target and viral reservoir. This may explain why obesity and diabetes are potential comorbidities for COVID-19 infections. Similar to the recently established adipocyte-myofibroblast transition, pulmonary lipofibroblasts located in the alveolar interstitium and closely related to classical adipocytes demonstrate the ability to transdifferentiate into myofibroblasts that play an integral part of pulmonary fibrosis. This may significantly increase the severity of the local response to SARS-CoV-2 in the lung. To reduce the severity and mortality associated with COVID-19, we propose to probe for the clinical response to thiazolidinediones, peroxisome proliferator activated receptor γ agonists that are well-known antidiabetic drugs. Thiazolidinediones are able to stabilize lipofibroblasts in their "inactive" state, preventing the transition to myofibroblasts and thereby reducing the development of pulmonary fibrosis and stimulating its resolution.

Assessment of risk, severity, mortality, glycemic control and antidiabetic agents in patients with diabetes and COVID-19: A narrative review

AIMS

Rising prevalence of non-communicable diseases world-wide has made diabetes an important comorbidity in patients with coronavirus disease-19 (COVID-19). We sought to review the risk, severity and mortality in COVID-19 and its relation to the glycemic control, and role of anti-diabetic agents in patients with diabetes.

METHODS

A Boolean search was made in PubMed, MedRxiv and Google Scholar database until May 10, 2020 and full articles with supplementary appendix were retrieved using the specific key words related to the topic.

RESULTS

There is a high prevalence of diabetes in patients with COVID-19. Patients with diabetes had a significantly more severe variety of COVID-19 and increased mortality, compared to the groups without diabetes. Moreover, poor glycemic control is associated with a significantly higher severe COVID-19 and increased mortality, compared to the well-controlled glycemic groups. No data currently available for or against any anti-diabetic agents in COVID-19.

CONCLUSIONS

Diabetes, in particular poorly-controlled group is associated with a significantly higher risk of severe COVID-19 and mortality. This calls for an optimal glycemic control and an increased emphasis on future preventative therapies including the vaccination programs for these groups in addition to the traditional risk prevention such as social distancing and self-isolation.

Course and treatment of diabetes mellitus in the context of COVID-19

In 2020, the world is facing a historically unparalleled public health challenge associated with the invasion of the new severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). This is also a challenge for the healthcare systems worldwide. Patients with diabetes mellitus (DM) are most vulnerable to COVID-19 because of the peculiarities of their immune response to a virus attack and due to their high susceptibility to viral activity because of hyperglycemia and other comorbid conditions and obesity that often accompany DM. The severity of the COVID-19 disease requires a mandatory review of the usual anti-hyperglycemic therapy. Maintaining optimal glycemic control and preventing the development of ketoacidosis remain extremely important; therefore, insulin becomes the priority drug for glycemic control in most cases. The search for new drugs to fight against the coronavirus infection continues with new randomised clinical drug trials being launched. Innovative anti-diabetic agents are also being tested as candidates for potentially effective anti-coronavirus agents.

Respiratory outcomes of metformin use in patients with type 2 diabetes and chronic obstructive pulmonary disease

Few studies investigated the respiratory outcomes of metformin use in patients with coexistent type 2 diabetes mellitus (T2DM) and chronic obstructive pulmonary disease (COPD). We want to compare the long-term respiratory endpoints of metformin use and nonuse in patients with T2DM and COPD. This retrospective cohort study enrolled patients with T2DM and COPD from Taiwan’s National Health Insurance Program between January 1, 2000, and December 31, 2012. Main outcomes were hospitalized bacterial pneumonia, hospitalization for COPD, noninvasive positive pressure ventilation (NIPPV), invasive mechanical ventilation (IMV), and lung cancer. In total, 20,644 propensity score-matched metformin users and nonusers were assessed. The adjusted hazard ratios (95% confidence intervals) of metformin use relative to nonuse for bacterial pneumonia, hospitalization for COPD, NIPPV, IMV, and lung cancer were 1.17 (1.11–1.23), 1.34 (1.26–1.43), 0.99 (0.89–1.10), 1.10 (1.03–1.17), and 1.12 (0.96–1.30). Metformin use also exhibited significant dose–response relationship with respect to the risks of bacterial pneumonia, hospitalization for COPD and IMV. Consistent results were found in the sensitivity test. This nationwide cohort study demonstrated that in patients with T2DM and COPD, metformin use was associated with higher risks of pneumonia, hospitalization for COPD, and IMV. If patients with COPD use metformin, vigilance with regard to their pulmonary condition may be required.

Diabetes and COVID-19: evidence, current status and unanswered research questions

Patients with diabetes who get coronavirus disease 2019 (COVID-19) are at risk of a severe disease course and mortality. Several factors especially the impaired immune response, heightened inflammatory response and hypercoagulable state contribute to the increased disease severity. However, there are many contentious issues about which the evidence is rather limited. There are some theoretical concerns about the effects of different anti-hyperglycaemic drugs. Similarly, despite the recognition of angiotensin converting enzyme 2 (ACE2) as the receptor for severe acute respiratory syndrome coronavirus 2 (SARS CoV-2), and the role of ACE2 in lung injury; there are conflicting results with the use of angiotensin converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARB) in these patients. Management of patients with diabetes in times of restrictions on mobility poses some challenges and novel approaches like telemedicine can be useful. There is a need to further study the natural course of COVID-19 in patients with diabetes and to understand the individual, regional and ethnic variations in disease prevalence and course.

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.

Peroxisome Proliferator-Activated Receptor Gamma (PPAR) Suppresses Inflammation and Bacterial Clearance during Influenza-Bacterial Super-Infection

Influenza virus is among the most common causes of respiratory illness worldwide and can be complicated by secondary bacterial pneumonia, a frequent cause of mortality. When influenza virus infects the lung, the innate immune response is activated, and interferons and inflammatory mediators are released. This "cytokine storm" is thought to play a role in influenza-induced lung pathogenesis. Peroxisome proliferator-activated receptor gamma (PPARγ) is a member of the nuclear hormone receptor super-family. PPARγ has numerous functions including enhancing lipid and glucose metabolism and cellular differentiation and suppressing inflammation. Synthetic PPARγagonists (thiazolidinediones or glitazones) have been used clinically in the treatment of type II diabetes. Using data from the National Health and Nutrition Examination Survey (NHANES), diabetic participants taking rosiglitazone had an increased risk of mortality from influenza/pneumonia compared to those not taking the drug. We examined the effect of rosiglitazone treatment during influenza and secondary bacterial (Methicillin resistant Staphylococcus aureus) pneumonia in mice. We found decreased influenza viral burden, decreased numbers of neutrophils and macrophages in bronchoalveolar lavage, and decreased production of cytokines and chemokines in influenza infected, rosiglitazone-treated mice when compared to controls. However, rosiglitazone treatment compromised bacterial clearance during influenza-bacterial super-infection. Both human and mouse data suggest that rosiglitazone treatment worsens the outcome of influenza-associated pneumonia.