Abnormality of left ventricular sympathetic nervous function assessed by (123)I-metaiodobenzylguanidine imaging in patients with COPD

Systemic Manifestations of COPD and the Impact of Dual Bronchodilation with Tiotropium/Olodaterol on Cardiac Function and Autonomic Integrity

Background: Chronic obstructive pulmonary disease (COPD) has significant systemic manifestations, including cardiovascular morbidity. The main aim of our study was to evaluate the effect of short-term COPD treatment with tiotropium/olodaterol (TIO/OLO) 5/5 μg on cardiac function and autonomic integrity. Methods: Twenty-nine patients with newly diagnosed moderate-to-severe COPD were enrolled. We performed pulmonary function tests, cardiac magnetic resonance, cardiac 123I-metaiodobenzylguanidine (123I-MIBG) imaging and analysis of blood biomarkers on our study subjects. The correlations between the tests' results were evaluated at baseline. The changes in pulmonary and cardiac parameters from baseline through 12 weeks were assessed. Results: Significant associations between pulmonary function tests' results and high-sensitivity C-reactive protein (hs-CRP), as well as interleukin-22 (IL-22), were observed at baseline. Treatment with TIO/OLO significantly improved lung function as measured by spirometry and body plethysmography. Moreover, we found that the cardiac index increased from 2.89 (interquartile range (IQR) 1.09) to 3.21 L/min/m2 (IQR 0.78) (p = 0.013; N = 18) and the late heart-to-mediastinum ratio improved from 1.88 (IQR 0.37) to 2 (IQR 0.41) (p = 0.026; N = 16) after 12 weeks of treatment. Conclusions: Treatment with TIO/OLO improves lung function and positively impacts cardiac function and autonomic integrity, suggesting that dual bronchodilation might have a potential in decreasing the risk for cardiac events in COPD. Hs-CRP and IL-22 might be beneficial in determining the intensity of systemic inflammation in COPD. Further research with a larger cohort is needed to enhance the initial results of this study.

Screening for comorbidities in COPD

Due to growing recognition of comorbidities, COPD is no longer considered a disease affecting only the respiratory system. Its management now entails the early diagnosis and treatment of comorbidities. However, although many studies have examined the impact of comorbidities on the evolution of COPD and patients' quality of life, very few have explored the means to systematically identify and manage them. The aims of this article are to summarise the state of current knowledge about comorbidities associated with COPD and to propose a possible screening protocol in the outpatient setting, emphasising the areas needing further research.

Review: Systemic consequences of COPD

Chronic obstructive pulmonary disease (COPD) is a highly prevalent chronic lung condition, affecting ∼10% of adults over the age of 40 years in the western world. Research over the past 10 years has shown that COPD is more than just a lung disorder; it affects other end-organs including the cardiovascular and the musculoskeletal systems, making it a multi-component, multi-system disease. COPD increases the risk for ischemic heart disease, stroke, osteoporosis, cachexia, and muscle weakness by two to threefold, independent of other factors such as smoking and age. The mechanisms by which COPD affects these end-organs, however, are unclear. In this paper, we review some of the common and serious extra-pulmonary manifestations of COPD and the potential mechanisms by which they can be linked with COPD.

Blood Pressure Profile and Hypertensive Organ Damage in COPD Patients and Matched Controls. The RETAPOC Study

BACKGROUND

Several studies suggest that there is a pathogenic link between chronic obstructive pulmonary disease (COPD) and cardiovascular diseases. On the other hand, increased sympathetic tone has been described in several respiratory diseases. Our objective was to determine whether hypertension mediated by sympathetic overactivity is a mechanism that explains the association between COPD and cardiovascular diseases.

METHODS

Prospective nested case-control observational study; 67 COPD patients were matched 1:1 by sex and age to controls with smoking history. 24 hour-blood pressure monitoring, urinary catecholamines and their metabolites measurement, echocardiography, carotid ultrasound examination, nocturnal oximetry and retinography were performed.

FINDINGS

classic cardiovascular risk factors and comorbidities were similarly distributed between cases and controls. No significant differences for blood pressure variables (difference for mean systolic blood pressure: -0·13 mmHg; 95% CI: -4·48,4·20; p = 0·94; similar results for all blood presssure variables) or catecholamines values were found between both groups. There was a tendency for lower left ventricle ejection fraction in the COPD cases, that approached statistical significance (64·8 ± 7·4 vs 67·1 ± 6·2, p = 0·05). There were no differences in the retinal arteriovenous ratio, the carotid intima-media thickness, or the number of carotid plaques, between cases and controls. Fibrinogen values were higher in the COPD group (378·4 ± 69·6 vs 352·2 ± 45·6 mg/dL, p = 0·01) and mean nocturnal oxygen saturation values were lower for COPD patients (89·0 ± 4·07 vs 92·3 ± 2·2%, p < 0·0001).

INTERPRETATION

Hypertension induced by sympathetic overactivity does not seem to be a mechanism that could explain the association between COPD and cardiovascular disease.

Impact of aging on cardiac sympathetic innervation measured by 123I-mIBG imaging in patients with systolic heart failure

PURPOSE

Sympathetic nervous system (SNS) hyperactivity is a salient characteristic of chronic heart failure (HF) and contributes to the progression of the disease. Iodine-123 meta-iodobenzylguanidine (¹²³I-mIBG) imaging has been successfully used to assess cardiac SNS activity in HF patients and to predict prognosis. Importantly, SNS hyperactivity characterizes also physiological ageing, and there is conflicting evidence on cardiac ¹²³I-mIBG uptake in healthy elderly subjects compared to adults. However, little data are available on the impact of ageing on cardiac sympathetic nerve activity assessed by ¹²³I-mIBG scintigraphy, in patients with HF.

METHODS AND RESULTS

We studied 180 HF patients (age = 66.1 ± 10.5 years [yrs]), left ventricular ejection fraction (LVEF = 30.6 ± 6.3 %) undergoing cardiac ¹²³I-mIBG imaging. Early and late heart to mediastinum (H/M) ratios and washout rate were calculated in all patients. Demographic, clinical, and echocardiographic data were also collected. Our study population consisted of 53 patients aged >75 years (age = 77.7 ± 4.0 year), 67 patients aged 62-72 years (age = 67.9 ± 3.2 years) and 60 patients aged ≤61 year (age = 53.9 ± 5.6 years). In elderly patients, both early and late H/M ratios were significantly lower compared to younger patients (p < 0.05). By multivariate analysis, H/M ratios (both early and late) and washout rate were significantly correlated with LVEF and age.

CONCLUSIONS

Our data indicate that, in a population of HF patients, there is an independent age-related effect on cardiac SNS innervation assessed by ¹²³I-mIBG imaging. This finding suggests that cardiac ¹²³I-mIBG uptake in patients with HF might be affected by patient age.

Effects of different doses of dexmedetomidine on heart rate and blood pressure in intensive care unit patients

The aim of the present study was to observe and compare the sedative effect of different doses of DEX on heart rate (HR) and blood pressure (BP) in critically ill patients admitted to intensive care units (ICUs). The study included patients that were retained in ICUs and required sedation between January and March 2014. Patients were excluded if they had a BP of >200 mmHg, a HR of <60 bpm or were in a state of shock. The included patients were randomized into three groups: Group A, 1.0 µg/kg/10 min DEX; group B, 0.5 µg/kg/10 min DEX; and group C, 0.4 µg/kg/h DEX. After receiving these initial designated doses of DEX via an intravenous (IV) infusion pump for 10 min, the patients were maintained continuously at an identical dose of 0.4 µg/kg/h DEX. Ramsay score, HR, systolic blood pressure (SBP), diastolic blood pressure (DBP), breathing rate (BR) and peripheral capillary oxygen saturation (SpO₂) were recorded prior to the IV pump infusion and at 2, 4, 6, 8, 10, 60, 120, 180 and 240 min following infusion. Patients in groups A and B achieved sedation more rapidly compared with those in group C (P<0.05). HR decreased more significantly at 8 and 60 min after the initial IV pump infusion with DEX in groups A and B compared with group C (P<0.05). SBP decreased significantly at 10 min after IV pump infusion in group A compared with groups B and C (P<0.05). No significant difference existed in the SBP reduction trend between the three groups during the maintenance period. Therefore, the routine dose of DEX (0.4 µg/kg/h) provides an ideal sedative effect in ICU patients. The recommended loading dose for a more rapid sedation is 0.5 µg/kg/h. High loading doses of DEX via IV pump infusion should be avoided in elderly individuals, patients with acute exacerbation of chronic obstructive pulmonary disease and anemic patients, in whom combination medication, such as midazolam or propofol, may be considered when necessary.

Heart rate slopes during 6-min walk test in pulmonary arterial hypertension, other lung diseases, and healthy controls

Six-minute walk test (6MWT) continues to be a useful tool to determine the functional capacity in patients with vascular and other lung diseases; nevertheless, it has a limited ability to predict prognosis in this context. We tested whether the heart rate (HR) acceleration and decay slopes during the 6-m walk test are different in patients with pulmonary arterial hypertension (PAH), other lung diseases, and healthy controls. In addition, we assessed whether the HR slopes are associated with clinical worsening. Using a portable, signal-morphology-based, impedance cardiograph (PhysioFlow Enduro, Paris, France) with real-time wireless monitoring via a Bluetooth USB adapter we determined beat-by-beat HR. We included 50 subjects in this pilot study, 20 with PAH (all on PAH-specific treatment), 17 with other lung diseases (obstructive [n = 12, 71%] or restrictive lung diseases [5, 29%]), and 13 healthy controls. The beat-by-beat HR curves were significantly different among all three groups of subjects either during the activity or recovery of the 6MWT. HR curves were less steep in PAH than the other two groups (P < 0.001). HR acceleration rates were slower in patients with PAH or other lung diseases with progression of their disease (P < 0.001). In conclusion, the acceleration and decay slopes during 6MWT are different among patients with PAH, other lung diseases, and healthy controls. The HR slopes during 6MWT were steeper in patients without clinical worsening.

Abnormal heart rate recovery and chronotropic incompetence on exercise in chronic obstructive pulmonary disease

Chronotropic incompetence (CI; failure to reach the targeted heart rate (HR) on exercise) and a delayed HR recovery (HRR; ≤12 beats decline within the first minute after cessation) reflect autonomic dysfunction (AD) and predict adverse cardiac prognosis. As chronic obstructive pulmonary disease (COPD) is known to be associated with AD, we hypothesized that these patients may manifest these responses on exercise. The prevalence and predictors of these responses in COPD and their association with its severity have not been evaluated. Normoxemic, stable male patients with COPD ( n = 39) and 11 healthy controls underwent lung function testing and incremental leg ergometry. HR responses were monitored during exercise and recovery to compute the HRR and CI. Of all the patients, 33 (84.6%) had at least one of the two exercise responses as abnormal, with the majority (23, 58.9%) having both an abnormal HRR and CI. The frequency of abnormal responses increased with increasing Global Initiative for Chronic Obstructive Lung Disease stage and body mass index, airflow obstruction, dyspnoea and exercise capacity index. After adjusting for smoking history and post-bronchodilator forced expiratory volume in 1 second, only a reduced diffusion capacity for carbon monoxide predicted abnormal HRR, though weakly. We concluded that abnormal HRR and CI are common in patients with COPD. These responses are observed with increasing frequency as the severity of disease increases.

Chronotropic incompetence predicts mortality in severe obstructive pulmonary disease

We evaluated the prevalence of chronotropic incompetence (CI), a marker of autonomic dysfunction, and its prognostic value in patients with chronic obstructive pulmonary disease (COPD). We performed a retrospective analysis of 449 patients with severe COPD who underwent a cardiopulmonary exercise test, after excluding patients with lung volume reduction surgery, left ventricular dysfunction and those not in sinus rhythm. CI was defined as percent predicted heart rate reserve (%HRR). Events were defined as death or lung transplant during a median follow-up of 68 months. Median age was 61 years; median percent predicted forced expiratory volume in one second (%FEV1) of 25% and median %HRR of 33%. The hazard ratio for an event in the lowest quartile of %HRR, taking the highest quartile as reference, was of 3.2 (95% confidence interval: 2.1-4.8; p<0.001). In a multivariate regression model, %HRR was an independent predictor of events. In conclusion, CI was an independent and powerful outcome predictor in patients with severe COPD.

Effects of tiotropium on sympathetic activation during exercise in stable chronic obstructive pulmonary disease patients

BACKGROUND

Tiotropium partially relieves exertional dyspnea and reduces the risk of congestive heart failure in chronic obstructive pulmonary disease (COPD) patients. However, its effect on the sympathetic activation response to exercise is unknown.

AIMS

This study aimed to determine whether tiotropium use results in a sustained reduction in sympathetic activation during exercise.

METHODS

We conducted a 12-week, open-label (treatments: tiotropium 18 μg or oxitropium 0.2 mg × 3 mg), crossover study in 17 COPD patients. Treatment order was randomized across subjects. The subjects underwent a pulmonary function test and two modes of cardiopulmonary exercise (constant work rate and incremental exercise) testing using a cycle ergometer, with measurement of arterial catecholamines after each treatment period.

RESULTS

Forced expiratory volume in 1 second and forced vital capacity were significantly larger in the tiotropium treatment group. In constant exercise testing, exercise endurance time was longer, with improvement in dyspnea during exercise and reduction in dynamic hyperinflation in the tiotropium treatment group. Similarly, in incremental exercise testing, exercise time, carbon dioxide production, and minute ventilation at peak exercise were significantly higher in the tiotropium treatment group. Plasma norepinephrine concentrations and dyspnea intensity were also lower during submaximal isotime exercise and throughout the incremental workload exercise in the tiotropium treatment group.

CONCLUSION

Tiotropium suppressed the increase of sympathetic activation during exercise at the end of the 6-week treatment, as compared with the effect of oxipropium. This effect might be attributed to improvement in lung function and exercise capacity and reduction in exertional dyspnea, which were associated with decreases in respiratory frequency and heart rate and reduced progression of arterial acidosis.

Impact of chronic obstructive pulmonary disease severity on symptoms and prognosis in patients with systolic heart failure

BACKGROUND

Systolic heart failure (SHF) and chronic obstructive pulmonary disease (COPD) are frequently associated. The purpose of our study was to explore the impact of COPD severity on symptoms and prognosis in patients with SHF.

METHODS AND RESULTS

Chronic obstructive pulmonary disease was systematically screened by spirometry in 348 patients admitted for SHF from April 2002 to December 2006. Severity of COPD was defined according to the GOLD classification. Prevalence of COPD was 37.9 %. Patients' distribution according to GOLD stages I, II, II and IV were, respectively, 51.5, 37.9, 7.6 and 3.0 %. Severity of dyspnoea increases with GOLD stage. There was a significant correlation between NYHA stage and left ventricular ejection fraction in patients without COPD (R (2) = 0.03; P = 0.01) but not in patients with COPD. Mean follow-up was of 54.9 ± 27.4 months. Mortality was 46.6 % and was highest in the COPD group (53.8 vs. 42.3 %; P = 0.049). Kaplan-Meier survival curves showed that patients with GOLD stage I had the same prognosis than patients without COPD and mortality increased from GOLD stage II to stage IV. After multivariate analysis, GOLD stage and diuretics' dose were independently associated with mortality.

CONCLUSIONS

Chronic obstructive pulmonary disease is frequent in patients with SHF and increases mortality. Since dyspnoea is poorly specific of COPD in chronic heart failure patients, COPD remains underdiagnosed thus leading to inappropriate increase of diuretics' dose. COPD should be systematically screened in patients with SHF to adapt prescription of selective β1-blockers, and diuretics' dose and reduce the exposition to risk factors.

Cardiac injury in patients with COPD presenting with dyspnea: a pilot study

PURPOSE

The aim of this pilot study was to test the hypothesis that myocardial ischemia complicates the management of some patients with chest-pain-free chronic obstructive pulmonary disease (COPD) exacerbations.

METHODS

In this prospective, observational, cohort study, patients admitted to a 350-bed community teaching hospital, with dyspnea and a primary diagnosis of COPD exacerbation, were followed for enzymatic and electrocardiographic evidence of myocardial ischemia for the first 24 hours of hospital admission.

RESULTS

A total of 114 patients were studied. Overall, four patients had definite myocardial infarctions, one had definite myocardial ischemia and 14 had possible myocardial ischemia. In multiple logistic regression models, age, number of coronary risk factors, and amount of administered albuterol were not associated with myocardial injury.

CONCLUSION

While unrecognized myocardial injury is relatively rare in patients with an exacerbation of COPD, it occurs frequently enough to warrant some caution since beta-agonists are the mainstays of therapy.

Cardiovascular mortality and morbidity in chronic obstructive pulmonary disease: the impact of bronchodilator treatment

Chronic obstructive pulmonary disease (COPD) is a substantial health burden. Cardiovascular disease (CVD), the leading cause of death, frequently coexists with COPD, an effect attributed to high individual disease prevalences and shared risk factors. It has long been recognized that COPD, whether stable or during acute exacerbations, is associated with an excess of cardiac arrhythmias. Bronchodilator medications have been implicated in the excess CVD seen in COPD, either as an intrinsic medication effect or related to side-effects. Despite the theory behind increased pro-arrhythmic effects in COPD, the reported results of trials investigating this for inhaled formulations at therapeutic doses are few. Methodological flaws, retrospective analysis and inadequate adjustment for concomitant medications, including short-acting 'relief' bronchodilators and non-respiratory medications with known arrhythmia propensity, mar many of these studies. For most bronchodilators at therapeutic levels in stable COPD, we can be reassured of their safety from current studies. The exception to this is ipratropium bromide, where the current data indicate an association with increased cardiovascular adverse effects. Moreover, there is no proven benefit from combining short-acting beta-agonists with short-acting anticholinergics at high doses in the acute setting, and although this practice is widespread, it is associated with increased cardiovascular risk.

Long-acting beta2-agonists (LABA) in chronic obstructive pulmonary disease: efficacy and safety

COPD is characterized by progressive airflow obstruction which does not fully reverse to inhaled or oral pharmacotherapy. The management of patients with COPD has taken a totally new direction over the past 20 years, thank to the use of novel therapies aimed to improve and modify the natural history of COPD. Long-acting bronchodilators, including long-acting β₂-agonists (LABAs), were introduced several years ago in order to enhance improvements in lung function, health status related quality of life, and reduce the rate of exacerbations. These effects can be boosted by the combination of LABAs with long-acting anticholinergic, and/or with inhaled corticosteroids. Inhaled LABAs are commonly well tolerated although adverse effects such as tremor and palpitations are occasionally troublesome.

Inhaled beta2-adrenoceptor agonists: cardiovascular safety in patients with obstructive lung disease

Although large surveys have documented the favourable safety profile of beta(2)-adrenoceptor agonists (beta(2)-agonists) and, above all, that of the long-acting agents, the presence in the literature of reports of adverse cardiovascular events in patients with obstructive airway disease must induce physicians to consider this eventuality. The coexistence of beta(1)- and beta(2)-adrenoceptors in the heart clearly indicates that beta(2)-agonists do have some effect on the heart, even when they are highly selective. It should also be taken into account that the beta(2)-agonists utilised in clinical practice have differing selectivities and potencies. beta(2)-agonist use has, in effect, been associated with an increased risk of myocardial infarction, congestive heart failure, cardiac arrest and sudden cardiac death. Moreover, patients who have either asthma or chronic obstructive pulmonary disease may be at increased risk of cardiovascular complications because these diseases amplify the impact of these agents on the heart and, unfortunately, are a confounding factor when the impact of beta(2)-agonists on the heart is evaluated. Whatever the case may be, this effect is of particular concern for those patients with underlying cardiac conditions. Therefore, beta(2)-agonists must always be used with caution in patients with cardiopathies because these agents may precipitate the concomitant cardiac disease.

Neurohumoral activation as a link to systemic manifestations of chronic lung disease

COPD is a major cause of death and disability worldwide. Treatment of COPD improves lung function but is unlikely to slow the steady downhill course of the disease or reduce mortality. In COPD, numerous abnormalities can be found outside the lung. These include systemic inflammation, cachexia, and skeletal muscle dysfunction. Thus, COPD has been called a systemic disease. Convincing data demonstrate that COPD causes neurohumoral activation. By precedents derived from chronic heart failure and other diseases characterized by neurohumoral activation, we propose that the negative consequences of neurohumoral activation, namely inflammation, cachexia, effects on ventilation, and skeletal muscle dysfunction, give rise to a self-perpetuating cycle that contributes to the pathogenesis of COPD, and which may involve respiratory muscle dysfunction as well as systemic inflammation. This concept may further help explain the increased cardiovascular morbidity and mortality in COPD patients. Currently, little is known about the effect of treatments directed at neurohumoral activation and COPD. As this aspect of COPD becomes better understood, new insights may direct novel therapeutic approaches.

Systemic inflammatory response to exhaustive exercise in patients with chronic obstructive pulmonary disease

Systemic inflammation may be present in patients with chronic obstructive pulmonary disease (COPD). Exercise is known to elicit an inflammatory response. We hypothesized that the systemic inflammatory response to exercise might be exaggerated in COPD patients compared to healthy subjects. Sixteen COPD patients and 11 healthy subjects performed a maximal incremental bicycle test. Before and at maximal exercise arterial blood samples were taken to determine circulating catecholamines, (subsets of) leukocytes, acute phase proteins, creatine kinase and myoglobin. At rest, increased levels of norepinephrine and systemic inflammation were present in COPD. The response of catecholamines to exercise was lower in COPD patients (P<0.01), which in part was due to the lower maximal exercise capacity of these patients (P<0.01). Exercise-induced leukocytosis showed similar responses in both groups, but occurred at higher levels in COPD. Although patients had increased levels of CRP at rest (P<0.001), exercise did not affect acute phase proteins. No systemic signs of muscle damage were found. The present study shows that COPD patients are exposed to systemic inflammation that is intensified by exhaustive exercise. The inflammatory response in COPD is not exaggerated compared to healthy subjects but occurs at a higher level and is observed at lower external workload.

Relationship between the frequency of autonomic dysfunction and the severity of chronic obstructive pulmonary disease

OBJECTIVE

The relationship between the frequency of autonomic dysfunction (AD) and the severity of chronic obstructive pulmonary disease (COPD) has not been exactly known, despite its importance in the pathogenesis of COPD. Therefore, we aimed to evaluate the relationship between the clinical stage severity of the disease and the frequency of AD in COPD patients.

METHODS

The frequency and type of AD were determined according to the clinical severity of 35 stable COPD patients. The results were compared between the mild and moderate-severe COPD groups. Sympathetic system (SS) was evaluated with sympathetic skin response (SSR), QT and QTc intervals (ms) analyses. Parasympathetic system was evaluated with the heart rate interval variations (RRIV).

RESULTS

For the total group, an AD was detected in 20 patients (57%), a parasympathetic dysfunction (PD) in 14 (40%), a mixed-type dysfunction in five (14%) and a sympathetic dysfunction (SD) in only one patient (3%). For the 12 mildly affected patients, there were cases of isolated SD in only one patient (8.5%), isolated PD in five (42%) and AD in six patients (50%). For the 23 moderate-severe COPD patients, mixed AD was detected in five patients (22%), isolated PD in nine (39%) and AD in 14 patients (61%). There were no significant differences between the two patient groups, neither for isolated parasympathetic and sympathetic, mixed form nor for total AD (P>0.05).

CONCLUSIONS

The results suggested that PD was dominant in patients with COPD. However, the frequencies of autonomic parasympathetic and sympathetic dysfunction did not increase significantly with the severity of COPD. The severity of hypoxemia and/or airflow limitation may not be the only unique or definite reason for AD in COPD, as there was not an exact correlation between the presence of AD and the severity of airflow limitation and hypoxemia.

Post-exercise heart rate recovery and mortality in chronic obstructive pulmonary disease

Abnormal heart rate recovery (HRR) after exercise, a marker of cardiac autonomic dysfunction, is associated with poor prognosis in various populations. As chronic obstructive pulmonary disease (COPD) is associated with cardiac autonomic dysfunction, we tested the hypothesis that patients with COPD have a lower HRR than healthy people, and evaluated whether a delay in HRR is associated with an increased risk of mortality in COPD. The records of 147 COPD patients were reviewed (65.1+/-9.1 years, mean+/-sd, 42 women/105 men, forced expiratory volume in 1s (FEV1): 42+/-15% predicted) and compared to 25 healthy subjects (61.6+/-4.5 years, 5 women/20 men, FEV1: 100+/-14% predicted) during recovery after an exercise test. Heart rate was measured at peak exercise and at 1-min recovery, the difference between the two being defined as HRR (11+/-9 beats in COPD patients vs. 20+/-9 beats in healthy subjects, P < 0.0001). During a mean follow-up of 43.1+/-22.0 months, 32 patients died. Abnormal HRR (14 beats) was a strong predictor of mortality in COPD patients (adjusted hazard ratio: 5.12, 95% CI [1.54-17.00]). In conclusion, COPD patients have a lower HRR than healthy subjects, and have a worse prognosis when presenting abnormal HRR.

Impaired lung function and serum leptin in men and women with normal body weight: a population based study

BACKGROUND

Impaired lung function is a risk factor for cardiovascular morbidity. Whether circulating factors are responsible for this association is unknown. A study was undertaken to determine whether leptin, a hormone that can promote atherothrombosis, is raised in individuals with impaired lung function.

METHODS

Data from non-obese participants in the Third National Health, Nutrition, and Examination Survey (n=2808) were analysed to determine the relationship between circulating leptin levels and forced expiratory volume in 1 second (FEV(1)) values divided into quintiles (quintile 1, FEV(1) predicted < or =85.2%; quintile 2, 85.3-94.3%; quintile 3, 94.4-101.4%; quintile 4, 101.5-110.0%; and quintile 5, > or =110.1%).

RESULTS

Serum leptin levels changed along the FEV(1) gradient. The highest leptin levels were found in quintile 1 (geometric mean (GM) 5.42; interquartile range (IQR) 3.00-9.60 fg/l) and the lowest in quintile 5 (GM 4.94; IQR 2.80-9.10 fg/l). Adjustments for age, body mass index, and other confounders strengthened this relationship. Compared with quintile 5, the odds of having an increased serum leptin level in quintiles 1, 2, 3, and 4 were 2.26 (95% confidence interval (CI) 1.54 to 3.31), 2.20 (95% CI 1.52 to 3.17), 1.46 (95% CI 1.01 to 2.09), and 1.28 (95% CI 0.90 to 1.83), respectively.

CONCLUSION

Individuals with impaired lung function have raised serum leptin levels. Leptin may play a role in the pathogenesis of cardiovascular morbidity and mortality related to impaired lung function.