Pulmonary function in non-insulin-dependent diabetes mellitus

Restrictive Pulmonary Disease in Diabetes Mellitus Type II Patients

Background

The present study aimed to evaluate the proportion of restrictive pulmonary disease in individuals with diabetes mellitus type II patients.

Methodology

A cross-sectional study was performed at Liaquat University of Medical & Health Sciences between May 2020 and June 2021. All individuals aged between 40 and 65 years, irrespective of gender were included in the study. While those individuals with known obstructive lung diseases, blood disorders, or malignancy were excluded. Spirometry, total lung capacity (TLC), and carbon monoxide diffusing capacity (DLCO) measurements were conducted to obtain a pattern of restrictive disease in patients. Patients were divided into three main groups; i) prediabetes, ii) newly diagnosed cases of diabetes, iii) longstanding diabetes mellitus type II, and iv) control group. The parameters like the patients’ age, sex, medication, history of smoking, and cardiac diseases, among other demographics were recorded. The data collected was recorded on a predesigned proforma.

Results

The majority of the newly diagnosed cases, as well as long-standing diseases, were elderly males (p=0.014 and p<0.0001). Dyspnea was significantly correlated with longstanding diabetes mellitus type II as indicated by a higher mean score of 0.65 ± 0.10 (p=0.006). Smoking did not significantly correlate with diabetes mellitus type II. In patients with longstanding diabetes, 27 (14.4%) had a modified Medical Research Council (mMRC) score of greater than two while none of the controls had severe breathlessness. Reduced forced vital capacity (FVC) was detected in 16.0% of patients with longstanding diabetes and 12.8% in patients with newly diagnosed disease. Similar results were obtained for total lung capacity (TLC) and diffusing capacity (DLCO) (p=0.003 and p=0.02).

Conclusion

Diabetes mellitus type II is significantly associated with restrictive lung disease in patients as indicated by a high number of patients with longstanding diabetes in our study who were found to have restrictive lung disease and severe dyspnea. Screening for lung dysfunction could aid in optimum management of this debilitating disease.

Clinical characteristics and risk factors associated with mortality in patients with severe community-acquired pneumonia and type 2 diabetes mellitus

BACKGROUND

The present study was performed to investigate the impacts of type 2 diabetes mellitus (T2DM) on severe community-acquired pneumonia (SCAP) and to develop a novel prediction model for mortality in SCAP patients with T2DM.

METHODS

This was a retrospective observational study conducted in consecutive adult patients with SCAP admitted to the intensive care unit (ICU) of West China Hospital, Sichuan University, China, between September 2011 and September 2019. The primary outcome was hospital mortality. A propensity score matching (PSM) analysis model with a 1:2 ratio was used for the comparisons of clinical characteristics and outcomes between T2DM and nondiabetic patients. The independent risk factors were identified via univariate and then multivariable logistic regression analysis and were then used to establish a nomogram.

RESULTS

In total, 1262 SCAP patients with T2DM and 2524 matched patients without T2DM were included after PSM. Patients with T2DM had longer ICU length of stay (LOS) (13 vs. 12 days, P = 0.016) and higher 14-day mortality (15% vs. 10.8%, P < 0.001), 30-day mortality (25.7% vs. 22.7%, P = 0.046), ICU mortality (30.8% vs. 26.5%, P = 0.005), and hospital mortality (35.2% vs. 31.0%, P = 0.009) than those without T2DM. In SCAP patients with T2DM, the independent risk factors for hospital mortality were increased numbers of comorbidities and diabetes-related complications; elevated C-reactive protein (CRP), neutrophil to lymphocyte ratio (NLR), brain natriuretic peptide (BNP) and blood lactate; as well as decreased blood pressure on admission. The nomogram had a C index of 0.907 (95% CI: 0.888, 0.927) in the training set and 0.873 (95% CI: 0.836, 0.911) in the testing set, which was superior to the pneumonia severity index (PSI, AUC: 0.809, 95% CI: 0.785, 0.833). The calibration curve and decision curve analysis (DCA) also demonstrated its accuracy and applicability.

CONCLUSIONS

SCAP patients with T2DM had worse clinical outcomes than nondiabetic patients. The nomogram has good predictive performance for hospital mortality and might be generally applied after more external validations.

Association between diabetes mellitus and chronic rhinosinusitis with nasal polyps: A population-based cross-sectional study

OBJECTIVE

To investigate the association between physician-diagnosed diabetes mellitus (DM) and chronic rhinosinusitis (CRS) phenotypes in a national population-based study.

STUDY DESIGN

Retrospective cross-sectional study.

SETTING

Population-based survey data were collected by the Korean National Health and Nutrition Survey between January 2008 and December 2012.

PARTICIPANTS AND METHODS

A total of 34 670 participants aged over 19 years were enrolled in the Korea National Health and Nutrition Examination Surveys from 2008 to 2012. The relationship of CRS prevalence, with and without nasal polyps, with physician-diagnosed DM and non-DM were assessed. Differences in sinonasal symptoms between patients with and without DM were analysed in this cross-sectional study.

RESULTS

A significant association was observed between DM and CRS with nasal polyps after adjustment for multiple variables. No substantial association was observed between DM and CRS without nasal polyps. Among patients with CRS, olfactory dysfunction for >3 months was significantly more frequent in the DM group than in the non-DM group.

CONCLUSION

We demonstrated significant associations between DM and CRS with nasal polyps and olfactory dysfunction among patients with CRS in a large national clinical cohort study. The direct mechanism of the association between DM and CRS with nasal polyps should be further investigated to clarify the pathogenesis of CRS with nasal polyps.

Idiopathic pulmonary fibrosis and diabetes mellitus: a meta-analysis and systematic review

Background

Idiopathic pulmonary fibrosis (IPF) is a chronic diffuse interstitial lung disease, of which the etiology has been poorly understood. Several studies have focused on the relationship between IPF and diabetes mellitus (DM) in the past years but have failed to reach a consensus. This meta-analysis aimed to examine the association between diabetes to IPF.

Methods

We accumulated studies investigating the association between DM and IPF from databases including Medline, Cochrane Library, Embase, Web of Science, and China National Knowledge Infrastructure. RevMan 5.3 and the Newcastle–Ottawa Scale (NOS) were utilized to analyze the data and assess the quality of the included studies. The value of odds ratio (OR) with 95% confidence interval (CI) was used as the measure to estimate the risk of DM in IPF. Heterogeneity was assessed by I² statistics. We also performed subgroup analysis, meta-regression, and Egger’s test for bias analysis.

Results

Nine case–control studies with 5096 IPF patients and 19,095 control subjects were included in the present meta-analysis, which indicated a positive correlation between DM and IPF (OR 1.65, 95% CI 1.30–2.10; P < 0.0001). Meta-regression and subgroup analysis negated the influence of covariates like cigarette smoking, age and gender, but the heterogeneity existed and could not be fully explained.

Conclusion

IPF and DM may be associated, but the causal relationship remains indeterminate till now. Further rigorously designed studies are required to confirm the present findings and investigate the possible mechanisms behind the effect of DM on IPF.

Effect of Type 2 Diabetes Mellitus and Diabetic Medication on Pulmonary Function

Background:

Type 2 diabetes mellitus (T2DM) is a chronic condition with an impairing effect on multiple organs. Numerous respiratory disorders have been observed in patients with T2DM. However, the effect of T2DM on pulmonary function is inconclusive.

Aims:

In this study, we investigated the effect of T2DM on respiratory function and the correlation of glycemic control, diabetes duration and insulin intake.

Methods:

1500 patients were recruited for this study; 560 having T2DM for at least a year were included in the final data, in addition to 540 healthy volunteers. Forced expiratory volume in one second (FEV1), forced vital capacity (FVC), forced expiratory flow at 25-75% (FEF 25-75%), as well as FEV1/FVC ratio values were measured.

Results:

A two-sample t-test showed that z-scores produced by Al-Qerem et al.’s equations for FEV1, FVC, and FEF 25-75% were significantly lower for the T2DM group than the control group (p < 0.01). FEV1/FVC ratio in the T2DM group was significantly higher (p < 0.01). Multiple linear regression analysis found that glycemic control represented by HbA1c as well as disease duration were negatively associated with the pulmonary function (p < 0.01). However, insulin intake was found to have no significant correlation with pulmonary function.

Conclusion:

T2DM was linked to reduced pulmonary function and was consistent with a restrictive ventilation pattern. HbA1c, as well as disease duration, were found to be independent risk factors for reduced pulmonary function.

Diabetic lung, an underrated complication from restrictive functional pattern to pulmonary hypertension

In patients with type 1 and type 2 diabetes mellitus (DM), respiratory function abnormalities have been reported with regard to lung volumes, pulmonary diffusing capacity, control of ventilation, bronchomotor tone, and neuroadrenergic bronchial innervation. Indeed, the decrease in lung volumes and the impairment of diffusing capacity might have important clinical implications. Furthermore, there is an increasing evidence of a link between DM and pulmonary hypertension (PH) related to an involvement of the pulmonary vascular structures. These findings support the view of the lung as target organ in DM. In this paper, we briefly describe the main derangements of the respiratory system in DM and the inherent mechanisms.

When kidneys and lungs suffer together

A significant interaction between kidneys and lungs has been shown in physiological and pathological conditions. The two organs can both be targets of the same systemic disease (eg., some vasculitides). Moreover, loss of normal function of either of them can induce direct and indirect dysregulation of the other one. Subjects suffering from COPD may have systemic inflammation, hypoxemia, endothelial dysfunction, increased sympathetic activation and increased aortic stiffness. As well as the exposure to nicotine, all the foresaid factors can induce a microvascular damage, albuminuria, and a worsening of renal function. Renal failure in COPD can be unrecognized since elderly and frail patients may have normal serum creatinine concentration. Lungs and kidneys participate in maintaining the acid-base balance. Compensatory role of the lungs rapidly expresses through an increase or reduction of ventilation. Renal compensation usually requires a few days as it is achieved through changes in bicarbonate reabsorption. Chronic kidney disease and end-stage renal diseases increase the risk of pneumonia. Vaccination against Streptococcus pneumonia and seasonal influenza is recommended for these patients. Vaccines against the last very virulent H1N1 influenza A strain are also available and effective. Acute lung injury and acute kidney injury are frequent complications in critical illnesses, associated with high morbidity and mortality. The concomitant failure of kidneys and lungs implies a multidisciplinary approach, both in terms of diagnostic processes and therapeutic management.

Risk of empyema in patients with COPD

Objective

Pneumonia is one of the most common infectious diseases in patients with COPD. The risk of empyema in COPD is controversial, and its incidence has not been reported. The aim of our study was to determine the risk of empyema in COPD patients and to assess its risk factors.

Patients and methods

We used the National Health Insurance Research Database in Taiwan to conduct an observational cohort study. This study analyzed patients who were diagnosed with COPD between January 1, 2003 and December 31, 2009. The earliest date of COPD diagnosis was designated the index date. Patients who were younger than 40 years or had empyema before the index date were excluded.

Results

We analyzed 72,085 COPD patients in our study. The incidence of empyema was higher in the COPD group than in the non-COPD group (15.80 vs 4.34 per 10,000 person-years). The adjusted hazard ratio for empyema was 3.25 (95% CI =2.73–3.87) in patients with COPD compared with patients without COPD. COPD patients with only comorbidity of stroke, cancer, and chronic renal disease had adjusted hazard ratios of 1.88, 4.84, and 3.90, respectively.

Conclusion

The likelihood of developing empyema is higher in patients with COPD than in those without COPD. Some comorbidities, such as stroke, cancer, and chronic renal disease, are associated with an elevated risk for empyema in COPD patients.

Pulmonary Function and Sleep Breathing: Two New Targets for Type 2 Diabetes Care

Population-based studies showing the negative impact of type 2 diabetes (T2D) on lung function are overviewed. Among the well-recognized pathophysiological mechanisms, the metabolic pathways related to insulin resistance (IR), low-grade chronic inflammation, leptin resistance, microvascular damage, and autonomic neuropathy are emphasized. Histopathological changes are exposed, and findings reported from experimental models are clearly differentiated from those described in humans. The accelerated decline in pulmonary function that appears in patients with cystic fibrosis (CF) with related abnormalities of glucose tolerance and diabetes is considered as an example to further investigate the relationship between T2D and the lung. Furthermore, a possible causal link between antihyperglycemic therapies and pulmonary function is examined. T2D similarly affects breathing during sleep, becoming an independent risk factor for higher rates of sleep apnea, leading to nocturnal hypoxemia and daytime sleepiness. Therefore, the impact of T2D on sleep breathing and its influence on sleep architecture is analyzed. Finally, the effect of improving some pathophysiological mechanisms, primarily IR and inflammation, as well as the optimization of blood glucose control on sleep breathing is evaluated. In summary, the lung should be considered by those providing care for people with diabetes and raise the central issue of whether the normalization of glucose levels can improve pulmonary function and ameliorate sleep-disordered breathing. Therefore, patients with T2D should be considered a vulnerable group for pulmonary dysfunction. However, further research aimed at elucidating how to screen for the lung impairment in the population with diabetes in a cost-effective manner is needed.

Postural variation of pulmonary diffusing capacity as a marker of lung microangiopathy in Indian patients with type 2 diabetes mellitus

INTRODUCTION

Diabetes mellitus (DM) is characterized by the presence of chronic hyperglycemia and formation of advanced glycation end products (AGEs). Interaction between AGE and its receptor leads to endothelial damage and microangiopathy. This study was undertaken to investigate the possibility of using a postural variation of diffusing capacity as an early marker of lung microangiopathy and its correlation with the level of adhesion molecules, HbA1c, duration of diabetes, and insulin resistance in type 2 DM (T2DM) patients with and without microangiopathy.

MATERIALS AND METHODS

Forty patients having T2DM without any microangiopathy (n = 20) as well as with microangiopathy (n = 20), and 22 age and sex matched healthy controls were enrolled in this cross-sectional study. Measurement of lung volumes and capacities were done. DLco was measured in sitting and supine position. Levels of vascular cell adhesion molecule-1 (VCAM-1), E-selectin, fasting glucose, and insulin were estimated in plasma of the patients and compared with controls.

RESULTS

Restrictive type of ventilatory change was observed in DM patients. Diffusing capacity (% predicted) in the supine position (P < 0.0001), postural change in DLco (P < 0.0001), and coefficient of diffusion were significantly less in DM patients as compared to controls. Plasma levels of VCAM-1 were significantly higher in DM patients without microangiopathy and negatively correlated (r = -0.4054, P = 0.0094) with Δ DLco in all diabetic subjects. All patients had significantly higher insulin resistance.

CONCLUSION

Lack of postural increase in diffusing capacity in type 2 diabetic patients along with increased VCAM-1 levels could reflect the presence of an early microangiopathy of the small pulmonary vessels.

Association between diabetes and increased prevalence of paranasal sinus disease: a cross-sectional study in Japanese adults

BACKGROUND

The association between diabetes and paranasal sinus disease has not been thoroughly investigated.

METHODS

We cross-sectionally investigated the association between diabetes and the presence of paranasal sinus disease, which was confirmed by a head MRI scan in 1350 adults who underwent a health screening program focusing on brain diseases and metabolic syndrome. Logistic regression, which was adjusted for age, sex, body mass index, waist-to-hip ratio, hypertension, smoking status, alcohol intake, and white blood cell count, was performed to calculate the odds ratio (OR) of having paranasal sinus disease among adults with diabetes in relation to those without. The dose-response relationship between hemoglobin A1c (HbA1c) levels and the presence of paranasal sinus disease was also investigated.

RESULTS

Of the 1350 participants (mean age, 61.6 ± 10.0 years; 71.6% men), 220 diabetes cases were identified. Paranasal sinus disease was diagnosed in 151 adults. The adjusted OR of having paranasal sinus disease was 1.74 (95% confidence interval [CI], 1.12-2.71) in those with diabetes. The odds of having paranasal sinus disease increased with HbA1c levels. Compared to those with HbA1c of ≤5.4%, those with HbA1c of 5.5%-6.4%, 6.5%-7.9%, and ≥8.0% were more likely to have paranasal sinus disease, with adjusted ORs of 1.32 (95% CI, 0.88-1.98), 1.63 (95% CI, 0.86-3.09) and 2.71 (95% CI, 1.12-6.61), respectively (P for trend = 0.019).

CONCLUSIONS

Diabetes may be significantly associated with higher prevalence of paranasal sinus disease in Japanese adults. We should keep this increased risk in mind when a diabetic patient is suspected of having paranasal sinus disease.

Assessment of lung function by spirometry and diffusion study and effect of glycemic control on pulmonary function in type 2 diabetes mellitus patients of the eastern India

INTRODUCTION

There are so many complications involving eyes, kidneys, lungs and nerves associated with diabetes. But, pulmonary complications are poorly characterized among eastern Indian diabetic populations.

AIMS AND OBJECTIVES

To assess pulmonary function in patients with type 2 diabetes mellitus. To find out correlation of the pulmonary functions test variables with Glycemic control.

MATERIALS AND METHODS

Total of 60 type 2 diabetes patient of age between 35-55 y and same number of age and sex matched apparently healthy control individual were included in the present study. All subjects were evaluated for PFT by flow sensitive spirometer (RMS HELIOS-401), the spirometric parameters were measured as a percentage of predicted and DLCO (by single breath technique). HBA1c of all cases were measured and they were grouped according to HBA1c level (Group-a =>7%, Group-b =6%-7%, Group-c =<6%).

RESULTS

Significant differences in the spirometric parameters (FVC, FEV1/FVC) and diffusion capacity (DLCO% and DL/VA%) existed between cases and controls. There was a significant decrease in FVC, DLCO and DL/VA and significant increase in FEV1/FVC in that groups having HBA1c level >7% than the other groups. FEV1, FVC, DLCO, and DL/VA were negatively correlated with HbA1c where as FEV1/FVC has positive association with HbA1c.

CONCLUSION

Significant deterioration of lung function and diffusing capacity was observed in type 2 diabetes patients with poor glycemic control.

Alveolar Gas Exchange and Pulmonary Functions in Patients with Type II Diabetes Mellitus

BACKGROUND

The incidence of diabetes is increasing tremendously throughout the world especially in the developing countries. This disease affects various organs like eyes, nerves, kidneys and the heart. In this study, we investigated whether lungs are also one of the target organs of diabetes mellitus or not.

AIM

To assess the pulmonary function parameters including alveolar gas exchange in patients with Type 2 Diabetes mellitus and to find the influence of hyperglycaemia and duration of diabetes.

METHODOLOGY

This cross sectional study involved 30 type II diabetic patients of age 30-60 years attending the diabetic outpatient department of SRM Medical College & Research Centre and 30 age and sex matched non-diabetic subjects as controls. The glycated haemoglobin (HbA1c) levels, fasting and post prandial blood glucose levels, pulmonary function parameters such as Forced Vital Capacity (FVC), Forced Expiratory Volume in 1 second (FEV1), Forced Expiratory Volume Percentage (FEV1 /FVC), Peak Expiratory Flow Rate (PEFR), Forced Expiratory Flow (25 - 75%), Peak Inspiratory flow ( PIF), Forced Inspiratory Vital Capacity ( FIVC), Total Lung Capacity ( TLC),Diffusing capacity of lung for carbon monoxide( DLCO) were measured for all the participants using Easyone Pro computerised spirometer. DLCO was measured by single breath Carbon Monoxide (CO) diffusion test. The alveolar membrane permeability was assessed by evaluating the ratio of DLCO to Alveolar Ventilation (VA).

RESULTS

The pulmonary function parameters FVC, FEV1, PEFR, PIF, FIVC, TLC , DLCO and DLCO/VA were significantly low (p<0.05) in patients with type II diabetes mellitus when compared to control group. The DLCO and DLCO/VA were significantly lower (p<0.05) in patients with poor glycemic control(HbA1c > 7).

CONCLUSION

We conclude that the pulmonary function parameters like FVC, FEV1, PEFR, PIF, FIVC, TLC and alveolar gas exchange were significantly reduced in patients with type II diabetes. The patients with Type II diabetes mellitus had a restrictive pattern of respiratory abnormality. The patients with poor glycaemic control( HbA1c > 7) had reduced alveolar diffusion which was not dependent on the duration of diabetes. The impaired respiratory function may give way for the development of pulmonary complications. Spirometry can be used as a screening tool among diabetics as an early preventive measure.

Alteration of pulmonary function in diabetic nephropathy

BACKGROUND

Type 2 diabetes mellitus is increasing worldwide with an alarming rate. It is associated with the development of various chronic complications. The aim of this study was to explore the alteration of pulmonary function, and its association with renal complications in people with type 2 diabetes mellitus.

METHODS

This cross-sectional study was conducted on three groups; 40 diabetic subjects without nephropathy (urinary albumin<30 mg/day), 40 subjects with nephropathy (urinary albumin≥30 mg/day), and 40 healthy subjects as the control group. The subjects with nephropathy were divided into those with microalbuminuria (urinary albumin=30-300 mg/day) and those with macroalbuminuria (urinary albumin>300 mg/day) .Diabetic subjects were matched to the control group in terms of age, sex, and BMI. Pulmonary function tests were performed and the results were compared between groups.

RESULTS

Forced vital capacity (FVC; % predicted), forced expiratory volume in 1 second (FEV1; % predicted), and peak expiratory flow (PEF; % predicted) were significantly lower in subjects with diabetic nephropathy compared to the healthy controls (P<0.05). Meanwhile, in diabetic subjects, FVC and FEV1 were lower in those with diabetic nephropathy compared to those with normal albumin excretion (P<0.05). On the other hand, FEV1/FVC was significantly higher in diabetic people with nephropathy.Furthermore, a significant difference was observed between FVC and FEV1 in diabetic people with microalbuminuria compared to those with macroalbuminuria.

CONCLUSIONS

This study showed that the pulmonary function was impaired in people with Diabetes. The progression of diabetic nephropathy to more advanced stages was also associated with more impairment of pulmonary function.

Contributors to diffusion impairment in HIV-infected persons

Abnormal diffusing capacity is common in HIV-infected individuals, including never smokers. Aetiologies for diffusing capacity impairment in HIV are not understood, particularly in those without a history of cigarette smoking. Our study was a cross-sectional analysis of 158 HIV-infected individuals without acute respiratory symptoms or infection with the aim to determine associations between a diffusing capacity of the lung for carbon monoxide (D(LCO)) % predicted and participant demographics, pulmonary spirometric measures (forced expiratory volume in 1 s (FEV1) and FEV1/forced vital capacity), radiographic emphysema (fraction of lung voxels < -950 Hounsfield units), pulmonary vascular/cardiovascular disease (echocardiographic tricuspid regurgitant jet velocity, N-terminal pro-brain natriuretic peptide) and airway inflammation (induced sputum cell counts), stratified by history of smoking. The mean D(LCO) was 65.9% predicted, and 55 (34.8%) participants had a significantly reduced D(LCO) (<60% predicted). Lower D(LCO) % predicted in ever-smokers was associated with lower post-bronchodilator FEV1 % predicted (p<0.001) and greater radiographic emphysema (p=0.001). In never-smokers, mean±SD D(LCO) was 72.7±13.4% predicted, and D(LCO) correlated with post-bronchodilator FEV1 (p=0.02), sputum neutrophils (p=0.03) and sputum lymphocytes (p=0.009), but not radiographic emphysema. Airway obstruction, emphysema and inflammation influence D(LCO) in HIV. Never-smokers may have a unique phenotype of diffusing capacity impairment. The interaction of multiple factors may account for the pervasive nature of diffusing capacity impairment in HIV infection.

The diabetic lung--a new target organ?

Several abnormalities of the respiratory function have been reported in patients with type 1 and type 2 diabetes. These abnormalities concern lung volume, pulmonary diffusing capacity, control of ventilation, bronchomotor tone, and neuroadrenergic bronchial innervation. Many hypotheses have emerged, and characteristic histological changes have been described in the "diabetic lung", which could explain this abnormal respiratory function. Given the specific abnormalities in diabetic patients, the lung could thus be considered as a target organ in diabetes. Although the practical implications of these functional changes are mild, the presence of an associated acute or chronic pulmonary and/or cardiac disease could determine severe respiratory derangements in diabetic patients. Another clinical consequence of the pulmonary involvement in diabetes is the accelerated decline in respiratory function. The rate of decline in respiratory function in diabetics has been found to be two-to-three times faster than in normal non-smoking subjects, as reported in longitudinal studies. This finding, together with the presence of anatomical and biological changes similar to those described in the aging lung, indicates that the "diabetic lung" could even be considered a model of accelerated aging. This review describes and analyses the current insight into the relationship of diabetes and lung disease, and suggests intensifying research into the lung as a possible target organ in diabetes.

Role of quantitative chest perfusion computed tomography in detecting diabetic pulmonary microangiopathy

AIMS

Aim of the study was to determine the role of perfusion chest computed tomography (pCT) in evaluation of pulmonary diabetic angiopathy.

METHODS

18 never-smoking patients (10 diabetic patients and 8 healthy controls) underwent chest high resolution CT (HRCT) and then pCT scanning. In both groups, blood tests, biochemical analysis, fibrinogen, HbA(1c), spirometry, diffusion capacity for carbon monoxide (DLCO) and body pletysmography were performed.Following parameters of pulmonary perfusion have been analysed: blood volume (BV), blood flow (BF), mean transit time (MTT), time to peak (TTP) and permeability surface (PS).

RESULTS

there were no statistically significant differences between groups in terms of age, sex, BMI, forced expiratory volume in one second (FEV(1)), DLCO. Chest HRCT revealed no pathologies. Significantly higher values of chest pCT for BF (p=0.05), BV (p=0.05) and PS (p=0.01) have been found in diabetics in comparison to controls. No differences were found in MTT.

CONCLUSIONS

significant increase of perfusion parameters in diabetes seems to confirm pulmonary microangiopathy. The results indicate that further studies on application of pCT in diabetic patients may be beneficial for better understanding of lung microangiopathy, its diagnosing and monitoring.

Fatty diabetic lung: altered alveolar structure and surfactant protein expression

Pulmonary dysfunction develops in type 2 diabetes mellitus (T2DM) in direct correlation with glycemia and is exacerbated by obesity; however, the associated structural derangement has not been quantified. We studied lungs from obese diabetic (fa/fa) male Zucker diabetic fatty (ZDF) rats at 4, 12, and 36 wk of age, before and after onset of T2DM, compared with lean nondiabetic (+/+) rats. Surfactant proteins A and C (SP-A and SP-C) immunoexpression in lung tissue was quantified at ages 14 and 18 wk, after the onset of T2DM. In fa/fa animals, lung volume was normal despite obesity. Numerous lipid droplets were visible within alveolar interstitium, lipofibroblasts, and macrophages, particularly in subpleural regions. Total triglyceride content was 136% higher. By 12 wk, septum volume was 21% higher, and alveolar duct volume was 36% lower. Capillary basement membrane was 29% thicker. Volume of lamellar bodies was 45% higher. By age 36 wk, volumes of interstitial collagen fibers, cells, and matrix were respectively 32, 25, and 80% higher, and capillary blood volume was 18% lower. ZDF rats exhibited a strain-specific increase in resistance of the air-blood diffusion barrier with age, which was exaggerated in fa/fa lungs compared with +/+ lungs. In fa/fa lungs, SP-A and SP-C expression were elevated at age 14-18 wk; the normal age-related increase in SP-A expression was accelerated, whereas SP-C expression declined with age. Thus lungs from obese T2DM animals develop many qualitatively similar changes as in type 1 diabetes mellitus but with extensive lipid deposition, altered alveolar type 2 cell ultrastructure, and surfactant protein expression patterns that suggest additive effects of hyperglycemia and lipotoxicity.

The assessment of pulmonary diffusing capacity in diabetes mellitus with regard to microalbuminuria

OBJECTIVE

The current study was conducted to determine whether or not the lung is one of the target organs in the development of vascular complications in diabetic patients. We also investigated the relationship between pulmonary diffusing capacity and microalbuminuria.

MATERIALS AND METHODS

A total of 68 patients with type 2 diabetes and 44 with type 1 diabetes (male/female [M/F] n=19/49 and 15/29; age: 52.4+/-8.8 and 32.5+/-11 years;) and 80 healthy controls (M/F=22/58; age=40.1+/-12.4 years) were recruited for the study. All of the participants were evaluated with simple spirometric tests and a simple breath carbon monoxide (CO) diffusion test. CO lung diffusion capacity (DLCO) and the ratio of DLCO value to the alveolar volume (VA) were used to assess alveolar membrane permeability (DLCO/VA). Urinary albumin excretion (UAE) per day of the participants was also evaluated.

RESULTS

DLCO, DLCO% and DLCO/VA% values were significantly lower in diabetics than in the control group (p=0.006; p=0.039; p=0.003, respectively). UAE was inversely correlated with DLCO, DLCO/VA, DLCO/VA% and DLCO% (p=0.050; p=<0.001; p=0.001; p=0.004, respectively).

CONCLUSION

This study demonstrated that alveolar gas exchange capacity is significantly decreased in diabetic patients. Microalbuminuria may be one of the predictors of this decline.

Cross-sectional and prospective study of lung function in adults with type 2 diabetes: the Atherosclerosis Risk in Communities (ARIC) study

OBJECTIVE

The aim of this study was to test the hypothesis that diabetes is independently associated with reduced lung function, both cross-sectionally and longitudinally.

RESEARCH DESIGN AND METHODS

We conducted cross-sectional and prospective analyses of diabetes status and lung function decline using baseline and 3-year follow-up data on 1,100 diabetic and 10,162 nondiabetic middle-aged adults from the Atherosclerosis Risk in Communities (ARIC) Study. Forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV(1)) were measured at baseline and at the 3-year follow-up using standard spirometry.

RESULTS

At baseline, adults with diabetes had significantly lower predicted FVC (96 vs. 103%, P < 0.001) and predicted FEV(1) (92 vs. 96%, P < 0.001) than those without diabetes. These differences remained significant after adjustment for demographic characteristics, adiposity, smoking, physical activity index, education, and ARIC field center. Graded, inverse associations were observed between hyperglycemia, diabetes severity (i.e., duration of diabetes and types of antidiabetes medications), and FVC and FEV(1) (all P(trend) < 0.001). In prospective analyses, FVC declined faster in diabetic adults than in their nondiabetic counterparts (64 vs. 58 ml/year, P = 0.01). Diabetes severity as indicated by intensity of antidiabetic treatment also showed graded relationships with the rate of FVC decline (P < 0.01).

CONCLUSIONS

These data support the notion that the lung is a target organ for diabetic injury. Additional research is required to identify pathophysiologic mechanisms and to determine clinical significance.

Melatonin Administration Acutely Decreases the Diffusing Capacity of Carbon Monoxide in Human Lungs

BACKGROUND

Most physiological measurements of the pulmonary diffusing capacity use carbon monoxide (CO) as a tracer gas. Similar to CO, melatonin binds the hemoglobin in the blood.

OBJECTIVE

The present study was designed to assess the effect of exogenous melatonin administration on pulmonary functions including diffusing capacity for carbon monoxide (DL(CO)) in healthy subjects.

METHODS

The study was performed in a randomized, double-blind, placebo-controlled manner. DL(CO) was measured in 22 healthy male volunteers (age 18-25 years) who were randomized to melatonin (n = 11) and placebo administration (n = 11). At baseline, DL(CO), alveolar volume (V(A)) and other spirometric parameters such as forced expiratory volume in 1 s (FEV(1)), forced vital capacity (FVC), peak expiratory flow (PEF) and maximal voluntary ventilation (MVV) were measured. DL(CO) was then corrected for the hemoglobin concentration. Measurements were repeated in a double-blind fashion 60 min after the administration of melatonin (1 mg) or placebo.

RESULTS

DL(CO) was significantly decreased (39.31 +/- 4.75 vs. 34.82 +/- 6.18 ml/min/mm Hg) 60 min after the melatonin administration (p = 0.01), while FEV(1), FVC, FEV(1)/FVC, PEF and MVV values did not demonstrate significant differences. Placebo administration did not result in significant alteration in any of these parameters.

CONCLUSIONS

In healthy subjects, oral administration of melatonin acutely influences the DL(CO) without affecting other pulmonary function test results. We conclude that melatonin may have a reducing effect on the DL(CO) in the lungs.

Etiology and outcome of community-acquired pneumonia in patients with diabetes mellitus

STUDY OBJECTIVES

It has been suggested that diabetes mellitus is associated with an increased susceptibility to infection, the risk of using more aggressive therapeutic agents, and increased morbidity and mortality; however, current evidence supporting these events in the field of pneumonia is scarce. The aim of the present study was to provide information on clinical and microbiological characteristics and the outcome of community-acquired pneumonia in patients with diabetes mellitus.

DESIGN

Prospective study of cases.

SETTING

A university hospital in Lleida, Spain.

PATIENTS

During a 5-year period, we prospectively studied the clinical and radiologic characteristics, the spectrum of causative agents and other microbiological data, and the outcomes of 660 consecutive episodes of community-acquired pneumonia. Data derived from 106 patients with diabetes mellitus were analyzed and compared with data obtained from the remaining population.

MEASUREMENTS AND RESULTS

Patients with diabetes mellitus were significantly older (p = 0.001) and more frequently had other concomitant comorbid conditions (p = 0.018). Diabetes was also significantly associated with the development of pleural effusion (p = 0.015) and mortality (p = 0.002); for both events, diabetes remained as an independent predictive factor in multivariate analyses. By contrast, the incidence of the main etiologic agents, and the bacteremia or empyema rates did not show significant differences in relation to the remaining patients. In the subgroup of patients with diabetes, mortality was associated with the presence of multilobar infiltrates (p = 0.004), concomitant underlying diseases (p = 0.004), and some diabetes-related complications (nephropathy, p = 0.040; and vasculopathy, p = 0.002), although only multilobar infiltrates and comorbidities were selected as prognostic factors in the multivariate analysis.

CONCLUSIONS

In patients with community-acquired pneumonia, diabetes mellitus is associated with a poor prognosis, increasing the rate of pleural effusion and mortality. Our results suggest that this adverse outcome is more attributable to the underlying circumstances of patients than to uncommon microbiological findings.

The diabetic lung: relevance of alveolar microangiopathy for the use of inhaled insulin

The alveolar-capillary network receives the entire cardiac output and constitutes the largest microvascular organ in the body, making it highly susceptible to systemic microangiopathy. Owing to its large reserves, symptoms and disability develop later in the lung than in smaller microvasculature such as the kidney or retina despite a comparable severity of anatomic involvement. Hence, pulmonary impairment in diabetes mellitus is under-recognized. Nonetheless, respiratory autonomic neuropathy and structural derangement of the thorax and lung parenchyma develop in many asymptomatic diabetic patients; the pathophysiology parallels that in other target organs. Even subclinical loss of alveolar microvascular reserves can be quantified noninvasively from lung diffusing capacity and its components (membrane diffusing capacity and alveolar-capillary blood volume) measured at a given cardiac output at rest or during exercise. The alveolar diffusion-perfusion relation tracks the recruitment of microvascular reserves in a manner independent of physical fitness. This article addresses the importance and pathophysiologic basis of diabetic pulmonary involvement, the assessment of diabetic alveolar microangiopathy, and the relevance of this understanding for the emerging use of inhaled insulin.

Altered Exercise Gas Exchange as Related to Microalbuminuria in Type 2 Diabetic Patients

STUDY OBJECTIVE

Microalbuminuria in diabetes mellitus is a risk factor for cardiovascular disease. We hypothesized that microalbuminuria in type 2 diabetic patients is related to impaired cardiopulmonary function during exercise, and that the severity of impairment is correlated with the degree of microalbuminuria.

DESIGN

Twenty of each of the following categories of subjects performed symptom-limited cardiopulmonary exercise testing on a cycle ergometer: (1) type 2 diabetic patients with normoalbuminuria (daily urinary albumin excretion [UAE] < 30 mg/d); (2) type 2 diabetic patients with microalbuminuria (daily UAE, 30 to 300 mg/d); and (3) normal control subjects.

MEASUREMENTS AND RESULTS

Oxygen consumption (VO(2)) of patients with microalbuminuria was lower than that of control subjects at anaerobic threshold (AT) [p < 0.001], and was lower than both control subjects (p < 0.001) and patients with normoalbuminuria (p = 0.015) at peak exercise. There was a progressive worsening in gas exchange efficiency at the lungs, as measured by minute ventilation (VE)/carbon dioxide production (VCO(2)) at AT or DeltaVE/DeltaVCO(2) slope, (p = 0.006 and p = 0.019, respectively) going from control subjects to patients with normoalbuminuria and then to patients with microalbuminuria. Left ventricular ejection fractions and BP were similar in patients with normoalbuminuria and microalbuminuria. More patients with microalbuminuria (n = 9) than with normoalbuminuria (n = 2) demonstrated diastolic dysfunction (p = 0.013). These 11 patients had lower peak VO(2) values (p = 0.001) and higher daily UAE (p = 0.028). An inverse linear relationship was found between peak VO(2) and log(10) daily UAE (r = - 0.57, r(2) = 0.29, p < 0.001).

CONCLUSIONS

Abnormalities reflecting reduced oxygen transport and impaired gas exchange efficiency were found during exercise, and were especially profound in patients with microalbuminuria. These changes could be secondary to pulmonary microangiopathy and myocardial interstitial changes. Increases in capillary permeability to proteins may take place in the myocardium as they do in the kidneys, and contribute to impaired myocardial distensibility and hence diastolic dysfunction.

Lung function, insulin resistance and incidence of cardiovascular disease: a longitudinal cohort study

OBJECTIVES

To explore whether a reduced lung function is a risk factor for developing diabetes and insulin resistance (IR), and whether such relationship contributes to the largely unexplained association between lung function and incidence of cardiovascular disease (CVD).

DESIGN

Forced vital capacity (FVC) was assessed at baseline. Incidence of diabetes and IR [according to the homeostasis model assessment (HOMA) model] was assessed in a follow-up examination after 13.9 +/- 2.6 and 9.4 +/- 3.6 years for men and women, respectively. After the follow-up examination, incidence of CVD (stroke, myocardial infarction or cardiovascular death) was monitored over 7 years.

SETTING

Populations-based cohort study.

SUBJECTS

Initially nondiabetic men (n = 1436, mean age 44.6 years) and women (n = 896, mean age 49.8 years).

RESULTS

Prevalence of IR at the follow-up examination was 34, 26, 21 and 21%, respectively, for men in the first (lowest), second, third and fourth quartile of baseline FVC (P for trend <0.0001). The corresponding values for women were 30, 29, 25 and 17%, respectively (P for trend <0.001). Adjusted for potential confounders, the odds ratio (OR) for IR (per 10% increase in FVC) was 0.91 (CI: 0.84-0.99) for men and 0.89 (CI: 0.80-0.98) for women. FVC was similarly significantly associated with the incidence of diabetes (OR = 0.90, CI: 0.81-1.00), adjusted for sex and other confounders. The incidence of CVD after the follow-up examination was significantly increased only amongst subjects with low FVC who had developed IR (RR = 1.7, CI: 1.02-2.7).

CONCLUSION

Subjects with a moderately reduced FVC have an increased risk of developing IR and diabetes. This relationship seems to contribute to the largely unexplained association between reduced lung function and incidence of CVD.

Diabetes mellitus vs. Raynaud disease: different lung vascular bed disorders

BACKGROUND

In type II diabetes mellitus there are few data concerning pulmonary function abnormalities. In normal subjects and in patients with primary Raynaud phenomenon, cold pressor test induces a decrease in carbon monoxide single-breath diffusing capacity (DL,co) but not in secondary Raynaud phenomenon. Our objective was to assess evaluation of lung diffusion capacity postural changes in diabetes mellitus and in secondary Raynaud phenomenon, two diseases with different pulmonary capillaries functional disorders.

METHODS

Twenty-five patients with type II diabetes mellitus (mean age 52.24 years), 17 patients with secondary Raynaud phenomenon (mean age 47.06 years), non-smokers without pulmonary or heart disease, and 26 healthy matched subjects (mean age 47.50 years) underwent lung diffusion capacity measurements by single-breath method also corrected by alveolar volume (DL,co) in sitting and supine positions.

RESULTS

Patients with diabetes mellitus exhibited lower values of DL,co and DL,co/VA measurements in comparison with subjects with Raynaud phenomenon and control group (p <0.01). Additionally, they had a significant decrease in DL,co in supine compared to sitting position (83.88 +/- 16.53 vs. 89.68 +/- 18.03, p = 0.023). To the contrary, supine position in secondary Raynaud phenomenon and in control group after cold pressor test showed a significant increase in DL,co/VA (120.93 vs. 109.78 in Raynaud and 114.36 vs. 99.47 in control group, p <0.001).

CONCLUSIONS

Postural changes of lung diffusion capacity could be used as a simple, non-invasive method to detect vascular disease resulting from different pathophysiologic mechanisms such as diabetes mellitus and Raynaud phenomenon.