Klaus Rabe: incoming President of the ERS

Towards better management of COPD

Introduction

COPD—more than just tobacco smoke

World Lung Day: what, why, and where to?

Do we really need asthma–chronic obstructive pulmonary disease overlap syndrome?

Management of chronic obstructive pulmonary disease: Moving beyond the asthma algorithm

NICE guidelines are evidence based but will need regular updating

Asthma and chronic obstructive pulmonary disease (COPD) continue to have considerable impact on disease burden and mortality worldwide. Early diagnosis still remains a challenge, with low uptake of spirometry in many countries. Implementing best practice management for airways disease is a critical goal for health-care systems—the management now includes pharmacological and non-pharmacological approaches to the lung disease, as well as recognition and treatment of comorbidities. Finally, the pathogenesis of airways disease continues to be fertile field of investigation, in order to better prevent disease, slow progression and identify relevant biomarkers. A large number of studies published in Respirology in 2012 have addressed all of these important clinical and scientific issues, and made major contributions to advance this field and hopefully improve outcomes for patients with asthma and COPD. Despite years of research, the origins of asthma remain obscure. Although there is clearly a genetic disposition to developing asthma, gene-association studies have so far failed to reveal clear insights into the development of asthma (reviewed in Respirology in 20111), indicating that asthma is likely to result from a complex interaction between genes and environment. Moreover, marked changes in the prevalence of asthma in recent decades indicate that changing environmental exposures must be to blame. Air pollution is known to exacerbate asthma symptoms and has been one of the factors suspected of causing the disease in the first place. Gowers et al. reviewed the association between air pollution and asthma for the Department of Health in the United Kingdom.2 In fact, they found little evidence for an association between pollution and asthma prevalence. If anything, time trends indicated a negative rather than positive association, but there is some evidence for an increased incidence of asthma in people living very close to roads carrying heavy traffic. The overall impact of this traffic pollution on asthma incidence is not likely to be large. Air pollution of different kind was studied by Havstad et al. who studied the impact of early-life exposure to environmental tobacco smoke on the development of atopy by 2–3 years in a cohort of children.3 Using propensity score matching, they found that tobacco smoke exposure increased the risk of positive skin prick or specific immunoglobulin E (IgE) tests in children whose mothers were not atopic, but paradoxically decreased the risk in those with a positive history of maternal atopy. This interaction between maternal atopy and the effect of environmental tobacco smoke on children's risk for atopy may help to explain some of the conflicting data from previous studies. An accompanying editorial emphasizes that exposing children to tobacco smoke should of course be avoided because of the many other adverse effects,4 but the paper, like that of Gowers et al.,2 demonstrates the need to better understand how genes and environment interact to cause atopy. Other changes in lifestyle and exposures may also help to explain increases in asthma prevalence. The well-recognized association between asthma and obesity was reviewed in Respirology and the mechanism for the association continues to elude researchers.5 Changing dietary exposures could be part of the explanation. A novel association between soft drink consumption, tobacco smoking and airway disease was reported by Shi et al.6 In a large cross-sectional telephone survey of Australian adults, consumption of more than half a litre a day of soft drinks was associated with both asthma and COPD. The association was only apparent among smokers in whom soft drinks and smoking appeared to have additive effects. If these findings are confirmed in other studies, they suggest a lifestyle intervention to prevent airways disease. One of the problems in identifying the origins of asthma is that clinical asthma comprises a number of distinct phenotypes. It has recently been proposed that these phenotypes represent truly different diseases with different causes (also called ‘endotypes’) rather than simply being different and variable expressions of the same underlying pathology.7 Defining asthma phenotypes on the basis of the cellular profile of induced sputum has become increasingly important as studies indicate that eosinophilic airway inflammation responds better to corticosteroid treatment than neutrophilic inflammation.8 Phenotypes are increasingly used to target novel asthma treatments, such as the anti-interleukin (IL)-5 monoclonal antibody targeted to eosinophilic asthma.9 Specific treatments for non-eosinophilic asthma have not been established however. Choi et al. studied sputum inflammatory profiles in patients with refractory asthma requiring high-dose corticosteroid therapy selected from a large asthma cohort.10 Those with persistent airway obstruction had a longer duration of asthma and had predominantly neutrophilic inflammation, whereas refractory asthma without persistent airway obstruction was more likely to be eosinophilic. The authors suggest that this provides a rationale for developing new medications for individualized treatment in these patients. However, two studies in Respirology show that eosinophilic airway inflammation varies over time even in the absence of corticosteroid treatment. Hancox et al. found that the eosinophilic/non-eosinophilic classification was not stable over time in two clinical asthma treatment trails: even though the sputum phenotype was determined at a time when the patients were not taking any steroid treatment, nearly all patients with ‘non-eosinophilic asthma’ had raised sputum eosinophils at some point.11 Similarly, the study of Bacci et al. (discussed in the Airway Biology section) provided evidence that inflammatory phenotypes based on sputum cell analysis are not stable over time.12 Another report last year found that sputum phenotypes are not stable in children either.13 Hence, characterization of asthma and long-term treatment decisions should not be based on a single sputum specimen.14 Induced sputum analysis remains valuable for assessing patients with difficult asthma, but the resources required to obtain and analyse frequent sample will inhibit its widespread use. Although not yet established in the management of asthma, measuring of exhaled nitric oxide (eNO) offers a more practical way to monitor airway inflammation than monitoring of induced sputum.15 Affordable handheld electrochemical nitric oxide analysers are now available, making this a realistic possibility for many services. Kim et al. compared eNO measurements using the handheld Niox Mino (Aerocrine AB, Solna, Sweden) electrochemical analyser with a Sievers (GE Analytical Instruments, Boulder, CO, USA) chemiluminesence analyser.16 Correlation between the two machines was good (r = 0.88), but agreement in absolute values was only moderate: the Mino tended to give about 15% lower readings. The handheld machines are convenient but differences between machines need to be taken into account when interpreting eNO values. Although measuring airway inflammation is appealing, more simple clinical assessments remain the mainstay of asthma management. Ko et al. found that a single measurement of the Asthma Control Test—a score based on a simple 5-item questionnaire—correlated with asthma control assessments by physicians and predicted exacerbations and emergency health-care use over the following 6 months in a cohort of patients attending tertiary care in Hong Kong.17 The baseline Asthma Control Test score was better at predicting exacerbations than lung function, peak flow or eNO measurements. Simple management of asthma was also supported by a large randomized control trial comparing adjustment of inhaled steroid doses using eNO, clinical physician guidance and patient symptom-based adjustment using inhaled corticosteroids (ICS) each time they required β-agonist. No difference was found between the strategies, with the trends favouring patient symptom-led adjustment.9 Improvements in computed tomography (CT) scanning technology and lower radiation doses have enabled the use of high-resolution scans to study airway structure and differentiate between diseases, sites of inflammation and treatment response without the need for tissue biopsies.18 Kurashima et al. found that airway lumens were smaller in the 3rd- to 6th-generation bronchi in asthma but not COPD, whereas both diseases demonstrated airway wall thickening.19 These small airway diameters correlated with lung function in asthma not COPD. Hoshino and Ohtawa used high-resolution CT scans to assess changes in large airway remodelling before and after 24 weeks treatment with combination long-acting β-agonist (LABA) and ICS or ICS alone in a double-blind randomized controlled trial.20 Combination therapy reduced airway wall thickness and increased the airway luminal area to a greater extent than ICS alone. The improvements in airway wall thickness in the combination group correlated with reductions in sputum eosinophils and improvements in forced expiratory volume in 1 s (FEV1). The mechanisms for this positive interaction between ICS and LABA are not known, but the findings offer hope that airway remodelling can effectively treated and/or prevented by combination therapy. An accompanying editorial by King and Farah emphasizes the need for confirmatory and long-term studies as well as investigations of the effects on smaller airways that remain beyond the resolution of the scans.21 The findings of Hoshino and Ohtawa of a positive interaction between LABA and ICS on remodelling is relevant to the current concerns over the safety of LABA in asthma.20 Among the most controversial issues this year is the American Food and Drug Administration requirement that the manufacturers of LABA undertake large safety studies of the combination on LABA with ICS. It is accepted that using LABA without ICS is not acceptable in asthma, but it has been suggested that these large safety studies of combination therapy are futile because they will not be powered to address the question of whether they cause a small excess of asthma deaths.22 In the meantime, a recent meta-analysis demonstrates that withdrawing LABA once asthma control has been achieved, as currently recommended by the Food and Drug Administration, leads to a deterioration in control.23 Cough-variant asthma is another well-recognized but poorly understood phenotype. Ohkura et al. compared coughing during methacholine-induced bronchoconstriction in patients with cough-variant asthma (but normal cough sensitivity to capsaicin challenge) and normal controls.24 Patients with cough-variant asthma had increased cough during even mild methacholine-induced bronchoconstriction. After treatment with inhaled steroids, the number of coughs diminished to be similar to normal controls, indicating that increased cough sensitivity to bronchoconstriction is a feature of this disease variant, but that it responds to anti-inflammatory treatment. For non-asthmatic refractory chronic cough, an exciting discovery this year was that gabapentin is an effective treatment in a double-blind randomized controlled trial.25 Gabapentin is an anticonvulsant that is also used to treat neuropathic pain, suggesting that its effect on chronic cough may be due to suppression of central cough reflexes. The paradigm of Th1- versus Th2-mediated inflammation would suggest that asthma (predominantly a Th2 disease) would be less uncommon in sarcoidosis—regarded as a Th1 disorder. However, Wilsher et al. found that the prevalence of positive specific IgE tests for common aeroallergens (34%) and a history of asthma (21.5%) were similar in patients with sarcoidosis to that reported in the general population.26 In another study from the same group, Young et al. found that 44% of patients with sarcoidosis had airway hyperresponsiveness to histamine (a direct airway challenge), whereas only 11% were hyperresponsive to an indirect challenge using hypertonic saline.27 Hyperresponsiveness to histamine was more common in those with lower baseline FEV1 values and those with fibrotic and reticular patterns on lung CT. The findings suggest that the high prevalence of histamine responsiveness in patients with sarcoidosis is likely to be distinct from asthma (because of the low prevalence of hypertonic saline responsiveness) and is more likely to be due to airway remodelling caused by granulomatous airway inflammation. The development of COPD is related to both genetic and environmental factors. For genetic factors, a recent study by Guan et al. from China found that D2S388-5 microsatellite polymorphism located upstream of the surface lung surfactant protein B gene on chromosome 2 may be associated with susceptibility to COPD in Xinjiang Kazakhs.28 Another genetic factor, nucleotide-binding and oligomerization domain (NOD) 2 genes polymorphism, has also been found to have some potential association with COPD in a study from Japan. The distribution of NOD2 rs1077861 genotypes differed between COPD patients and non-COPD smokers and was associated with a lower FEV1 % predicted value in the TT when compared with the TA/AA genotypes.29 For environmental factors, exposure to noxious particles or gases is associated with the development of COPD.30 A study from Johannessen et al. found that exposure to environmental tobacco smoking during childhood was associated with COPD and respiratory symptoms in adulthood mainly in women in a cross-sectional study in Norway. In men, the most important risk factor is still acting smoking.31 The relationship of air pollution and COPD is reviewed by Ko and Hui.32 Outdoor air pollution (such as ambient air pollution) and indoor pollution (such as second-hand smoking and biomass fuel combustion exposure) are associated with the development of COPD and outdoor air pollution is a significant environmental trigger for acute exacerbation of COPD. Zeng et al. reviewed the aetiology of COPD in non-smoking subjects and risk factors may include genetic factors, long-standing asthma, outdoor air pollution, environmental smoke exposure, biomass smoke, occupational exposure, diet, recurrent respiratory infection in early childhood and tuberculosis.33 Interestingly, statins34 and even soft drink consumption6 have been found to have association with COPD. A cross-sectional study from Japan found that the prevalence of airflow limitation among patients who used statins was approximately five times lower than that among patients who did not use statins. However, statin use was not significantly associated with a lower prevalence of airflow limitation in multivariate analysis.34 Statins thus cannot be advocated for prevention of airflow obstruction at this stage. A study from South Australia assessed the relationship between soft drink consumption and presence of asthma/COPD in over 16 000 subjects.6 and noted the odds ratio for having COPD was 1.79 (95% confidence interval: 1.32–2.43) in multivariate analysis by comparing those who consumed more than half a litre of soft drink per day with those who did not consume soft drinks. The reason behind these associations is unclear and a causative relationship cannot be drawn from these studies. Comorbidities are common in COPD patients and the latest Global Initiative for Chronic Obstructive Lung Disease (GOLD) guideline has also emphasized that comorbid illness in COPD patients should be managed appropriately.30 The link between COPD and coronary artery disease is strong and complex. Coronary artery disease has a strong effect on the severity and prognosis of COPD and vice versa, including acute exacerbations.35 Ito and colleagues found that depression and sleep disorders were both common in patients with COPD.36 McSharry et al. found that sleep quality is poor in severe COPD patients with reduced sleep efficiency and reduced percentage of rapid eye movement sleep. There was a significant association between daytime hypoxaemia and sleep efficiency.37 However, depression, but not sleep disorder, is an independent risk factor for exacerbations and hospitalizations among COPD patients.36 The economic burden of COPD is huge and a recent study from Singapore showed that in 2009, COPD admissions represented 3.4% of all hospital discharges. Hospitalization was found to be the major cost driver, accounting for 73% of the total COPD burden, Between 2005 and 2009, attendances at primary care clinics, emergency departments and specialist clinics accounted for 3%, 5% and 17% of overall COPD costs, respectively.38 There are some new developments in the assessment of COPD using tools like CT and exercise tests. Degree of hyperinflation39 and airway dimensions18, 19 in COPD patients can be measured using CT parameters. Tanabe and colleagues applied a novel CT index to assess lung volume. This DLV% index measures the ratio of lung volume region adjacent to the diaphragm dome (D) to total lung volume (LV). Using this index, it was found that a reduced lung volume around the diaphragm correlated with lung hyperinflation and health-related quality of life, independent of emphysema severity.39 A recent study by Galban et al. adapted the parametric response map, a voxel-wise image analysis technique, for assessing COPD phenotype. In their study, whole-lung CT scans acquired at inspiration and expiration of COPD patients were analysed. Parametric response map identified the extent of functional small airways disease and emphysema as well as provided CT-based evidence that supports the concept that functional small airways disease precedes emphysema with increasing COPD severity.40 Phenotyping COPD by image biomarkers is currently under investigation and offers potential development of personalized therapy for COPD patients. There are also different field and laboratory tests for measuring exercise capacity in COPD patients. Hill and colleagues compared the 6-min walk test, incremental shuttle walk test and endurance shuttle walk test with a ramp cycle ergometer test in a group of patients with moderate COPD and found that these tests all elicited a similar peak rate of oxygen uptake and heart rate response. This suggested that that both self- and externally paced field tests can progress to high intensities.41 Field tests can probably offer a reasonable alternative for the evaluation of patients with moderate COPD.42 The revised was published in were indicated as the or in the treatment of all of patients with COPD. A new of and long-acting have as the most effective for control in patients with COPD. et al. reported the of one such when compared with in patients from 6 for found that provided significant and improvements in and in COPD with that reported in other from clinical indicate that may prevent acute exacerbations of However, the underlying mechanism for this effect is et al. showed that treatment in patients with COPD the and of both and by and This a effect of the in by the of and by the airway The long-term safety of this and its in to other treatment need evaluation before it a acute exacerbation of it is difficult for physicians to differentiate COPD from heart common and comorbidities. and colleagues the of for the diagnosis of in patients with severe acute exacerbations of COPD and in 2 care found that the was more in patients with normal function sensitivity and than those in and required adjustment of the to a et al. in a trial of patients with acute COPD and from heart compared treatment with versus reported more rapid in with the combination treatment but difference in This is a to the and treatment of heart during apparent COPD and sleep disorders are common and important in severe Ito et al. in a study of COPD patients and normal that only depression but not sleep disorders is associated with the increased risk of exacerbations and The management of and depression was the of a by and colleagues in they treatment with the of clinical on this important of COPD with sputum to exacerbations and poor quality of in patients with COPD. In a et al. that inhaled treatment may improve the quality of in patients with by sputum studies are to the of this is an important goal in patients with COPD.30 It quality of and the of greater and pulmonary is an effective way to in COPD long-term monitoring and of at is to the of any exercise In this et al. found that a value was correlated with severe This may be a practical of patients can and to with are and is a intervention for patients with acute exacerbations of COPD who to to treatment. It may be as the current of care in this clinical Moreover, in patients with COPD on the of and mortality from to However, there is a need to improve the practical assessment of the response to in the acute In this et al. reviewed the of for the of during acute However, they were to positive from randomized The clinical may be that of may not be a of response to and should continue to on parameters. the disease the treatment of COPD become less effective and symptoms become more for such patients need to early to complex with about values and for care including of et in a of the the approaches to care at the of in patients with severe interaction susceptibility to airway diseases such as asthma and COPD. association studies have found associations of specific single with the development of asthma or COPD. in Respirology have also on genetic of airway A meta-analysis of studies of the polymorphism in found increased risk of asthma in or with A genetic association study of COPD patients and non-COPD in Japan single in the genes and recognition that The A of single polymorphism rs1077861 in NOD2 was associated with increased risk of COPD, and NOD2 gene in with studies such as these interaction in inflammation and in the development of airway smoking is the major cause of other causes include air pollution and occupational In the development of childhood asthma, an and respiratory are The link between respiratory and Th2 has been demonstrated in asthma in with respiratory in induced airway inflammation and by and reduced to infection may also to asthma pathogenesis and as by studies of airway in In a of asthma, the as an for to by has been as a risk factor for In the Respirology on obesity and respiratory Farah and potential mechanisms for the effects of obesity in including of from tissue and changes that lung have found increased of tissue in patients with The of asthma is by Th2 IgE and cell with of the airway In non-eosinophilic asthma in some patients. In a study of patients with non-eosinophilic asthma of patients also had sputum during over 6 This was more common when they were treated with the alone without inhaled compared with This in Respirology supports the of LABA for asthma and the potential of airway inflammatory phenotype. The airway inflammation of COPD is by and A number of studies in Respirology have on other of are a of that and function more like but also link to the of were lower in the of patients with stable COPD and decreased during acute is a recognition that A study of lung tissue showed that from COPD patients and smokers had increased protein of compared with smoke exposure in increased of and increased and exposure to the smoke could inflammatory to and other of recognition in the Other have also been in COPD. of was in small airway of COPD patients and compared with in with gene of and from that had high Hence, of in the airways could to susceptibility to in the of COPD patients and Airway remodelling is an important feature of chronic In a study in airway of was increased in patients with severe asthma, compared with mild asthma or and was induced following bronchoconstriction with or has been to be for and is a potential of airway remodelling in The pathogenesis of COPD is by a response to environmental to lung that for inflammation, These have been in a number of studies in Respirology in the of may have effects in specific protein of was measured in the lung tissue of COPD with mainly in and was increased in sputum of COPD correlated with of lung function, and correlated with sputum and In another study, and tissue of were measured in from COPD patients and non-COPD of and as well as tissue of 1 and were increased in COPD, the of COPD is by acute as disease A study of patients with an exacerbation of COPD measured inflammatory biomarkers at and before of and were at the of the correlated with exacerbation severity and were reduced by the time of but not to normal of biomarkers behind clinical and could be in monitoring COPD studies into treatment in airways disease. In an asthma study, single in the region of the gene were associated with in a association study of subjects from clinical Although the function of is as yet in of by in airway increased protein of the suggesting a for in In the Respirology on into recent developments in tissue in to the The large airways have been for tissue with and or or In development of for the small airways has been more because of the and number of of the of lung will help to advance this the hope of for lung

Review question/objective The objective of this systematic review is to identify the best available research evidence related to the effectiveness of educational and supportive interventions for improving adherence to inhalation therapy in people with chronic respiratory diseases, focusing on measures of adherence and health outcomes. The specific review questions to be addressed are: 1. What is the effectiveness of educational and supportive interventions for improving adherence to inhalation therapy in terms of inhalation regimens and inhalation techniques in people with chronic respiratory diseases? 2. What is the effectiveness of educational and supportive interventions for improving adherence to inhalation therapy on health service utilization and patient outcomes including symptoms, pulmonary function, and quality of life? 3. What is the effectiveness of various designs, in terms of components, modes and intensities, of educational and supportive interventions for improving adherence to inhalation therapy? Inclusion criteria Types of participants This review will consider studies that include adults aged 18 or above, with a clinical diagnosis of chronic respiratory disease and prescribed self-administered inhalation therapy as a long term regular treatment, irrespective of the type of inhaler used. For the purposes of this review, "chronic respiratory diseases" is defined by WHO in 2007 as "the chronic diseases of the airways and other structures of the lung" (p.5). 1 Inhalation therapy is defined as "a treatment in which a substance is administered to the respiratory tract with inspired air". 6 This review will focus on inhalation of drugs. Those studies with prescribed administration of oxygen and water will be excluded. There is no universal standard for how long a treatment is undertaken to be defined as a "long term treatment". Acute episodic drug treatments, such as a course of antibiotics, will be excluded. Types of interventions of interest All educational interventions, with or without supportive programs, designed to improve the chronic respiratory disease sufferers inhalation technique and adherence to their prescribed inhalation therapy will be considered. Those studies that involve comparison of different types of inhalation medications, inhaler devices or inhalation methods to improve the adherence to inhalation therapy will be excluded. For the TRUNCATED AT 350 WORDS

UK COPD treatment: failing to progress

Chronic obstructive pulmonary disease (COPD) is an important differential diagnosis in patients with heart failure (HF). The primary aims were to determine the prevalence of COPD and to test the accuracy of self-reported COPD in patients admitted with HF. Secondary aims were to study a possible relationship between right and left ventricular function and pulmonary function. Prospective substudy. Systematic screening at 11 centres. Consecutive patients (n = 532) admitted with HF requiring medical treatment with diuretics and an episode with symptoms corresponding to New York Heart Association class III-IV within a month prior to admission. Forced expiratory volume in 1 s (FEV(1)) and forced vital capacity (FVC) were measured by spirometry and ventricular function by echocardiography. The diagnosis of COPD and HF were made according to established criteria. The prevalence of COPD was 35%. Only 43% of the patients with COPD had self-reported COPD and one-third of patients with self-reported COPD did not have COPD based on spirometry. The prevalence of COPD in patients with preserved left ventricular ejection fraction (i.e. LVEF >or=45%) was significantly higher than in patients with impaired LVEF (41% vs. 31%, P = 0.03). FEV(1) and FVC were negatively correlated with right ventricular end-diastolic diameter and tricuspid annular plane systolic excursion and FVC positively correlated with systolic gradient across the tricuspid valve. Chronic obstructive pulmonary disease is frequent in patients admitted with HF and self-reported COPD only identifies a minority. The prevalence of COPD was high in both patients with systolic and nonsystolic HF.

Objective. Chronic diseases interfere with the life situation of the affected person in different ways. The aim was to compare the burden of disease in three chronic diseases – chronic obstructive pulmonary disease (COPD), rheumatoid arthritis (RA), diabetes mellitus (DM) – and in healthy subjects, with a particular interest in physical activity, quality of life, and psychological health. Design. Cross-sectional, observational study. Setting and subjects. Postal survey questionnaire to a stratified, random population of 68 460 subjects aged 18–84 years in Sweden. The subjects included were 40–84 years old (n = 43 589) and data were analysed for COPD (n = 526), RA (n = 1120), DM (n = 2149) and healthy subjects (n = 6960). Result: Some 84% of subjects with COPD, 74% (RA), 72% (DM), and 60% in healthy subjects (p < 0.001, COPD versus RA, DM, and healthy subjects) had a physical activity level considered too low to maintain good health according to guidelines. Quality of life (EuroQol five-dimension questionnaire, EQ-5D) was lower in COPD and RA than in DM. Anxiety/depression was more common in subjects with COPD (53%) than in those with RA (48%) and DM (35%) (p < 0.001, COPD versus RA and DM), whereas mobility problems were more common in RA (55%) than COPD (48%) and DM (36%) (p < 0.001, RA versus COPD and DM). All differences between groups remained significant after adjusting for age, sex, and socioeconomic background factors. Conclusion. Subjects with chronic diseases had a low level of physical activity, most evident in subjects with COPD. COPD and RA had a higher negative impact on quality of life than DM. Our results indicate that increased attention regarding physical inactivity in subjects with chronic diseases is needed to minimize the burden of disease.

Pulmonary diseases, especially pneumonia, have been among the most frequent complications of HIV since early in the AIDS epidemic [1–3]. In parallel with other complications of HIV, the spectrum of pulmonary diseases currently reflects a substantial burden of non-AIDS-defining chronic diseases as HIV-infected patients are aging on antiretroviral therapy (ART) [4–9]. A leading cause of global mortality [10,11], chronic obstructive pulmonary disease (COPD) is the most common chronic lung disease diagnosed in HIV-infected patients, encountered in approximately 20% of patients in different cohorts [4,6,8,9,12]. However, our understanding of the impact of chronic HIV infection on lung health over time remains incomplete. Does HIV cause a unique impairment in lung health, or is HIV a 'second hit' to accelerate the toxic effects of other exposures such as cigarette smoking to cause typical diseases like COPD? Or, is the increased burden of lung diseases in HIV merely explained by a greater prevalence of smoking, drug use, respiratory infections, and other exposures that are common in many HIV-infected populations? To date, whether HIV infection is an independent risk factor for chronic lung diseases, particularly COPD, remains uncertain. Cross-sectional studies in HIV-infected and uninfected persons comparing the prevalence of COPD, defined by the presence of fixed airflow obstruction on spirometry, have had somewhat conflicting results [6,8]. Disentangling the effects of numerous behavioral, environmental, and occupational exposures, and the contribution of comorbid conditions from those of HIV infection on lung health is challenging, particularly in cross-sectional analyses. The current work by Drummond et al. [13] in this month's issue of AIDS expands our knowledge of the effects of HIV infection on lung health with one of the first longitudinal studies of lung function decline in HIV-infected compared to demographically and behaviorally similar HIV-uninfected persons in the combination ART era. They examined the effect of HIV infection, specifically HIV viral load and CD4 cell count, on lung function decline in a cohort of injection drug users, the AIDS Linked to the IntraVenous Experience (ALIVE) study. Several findings from the study will be important both to clinicians caring for HIV-infected patients and to researchers trying to understand the causes of HIV-associated lung disease. First, absolute values of airflow, namely, the forced expiratory volume in 1 second (FEV1) and the forced vital capacity (FVC), were significantly lower in HIV-infected compared with uninfected participants in analyses adjusted for demographic, behavioral, and clinical factors; whether this is because of a prior period of accelerated decline in lung function such as from earlier episodes of pneumonia, or due to a lower attainment of overall lung function such as from earlier initiation of smoking or childhood illness, or for other reasons, is not known. Second, the rate of decline in lung function, as measured by the change in FEV1 and the FVC, was similar in HIV-infected and uninfected drug users overall. The decrease in FEV1 was nonsignificantly higher, and the decrease in FVC was greater, but of borderline significance in HIV-infected individuals (P = 0.05). Given the nearly universal smoking history and high rate of current drug use, the decrements in lung function over time are overall surprisingly small. There may have also been differences in prescription of bronchodilators that had an unmeasured effect on the results, and bronchodilator testing was not administered during spirometry. The most intriguing finding is that despite the lack of difference in lung function decline in the overall HIV-infected population compared to HIV-uninfected, when stratified by HIV disease severity, a higher HIV viral load (defined as >75 000 copies/ml) and a lower CD4 cell count (considering absolute values as well as CD4%) were associated with a greater rate of decline in both FEV1 and FVC over time. HIV-infected participants with CD4 cell counts of 200 cells/μl and below were significantly more likely to have a greater decline in FEV1 and FVC over time compared to HIV-uninfected individuals. In contrast, decline in lung function was similar in HIV-infected persons with CD4 cell count above 200 cells/μl and those without HIV. These data raise the possibility that ART and better control of HIV may ameliorate the decline in lung function in HIV, although previous studies have found an association of ART with worse airway obstruction [9,14] and time-updated ART use was not significantly associated with change in lung function in the current analyses. Residual confounding in human studies always remains as a potential explanation for these findings. However, Drummond et al. assessed other risk factors in a rigorous fashion and utilized time-updated covariates to account for factors such as current smoking status, recent HIV disease severity, and intercurrent respiratory infection [13]. In particular, increased risk for pneumonia in patients with poorly controlled HIV could certainly mediate rate of decline in lung function. Notably, the incidence of pneumonia was low, especially in those with CD4 cell counts below 100. However, assuming that capture of pneumonia events was complete, these data support that the association of HIV viremia and/or immunodeficiency with greater lung function decline is independent of pneumonia and other major confounders. These findings raise a number of intriguing questions. Why is uncontrolled HIV disease associated with a greater risk of decline in lung function? Is the association with higher HIV viral load due to effects of the virus itself, accompanying inflammation, and/or immune activation? Does poorly controlled HIV increase the risk for colonization with microorganisms that may play a role in COPD pathogenesis (such as with Pneumocystis[15])? Furthermore, is the effect of HIV viremia or immunodeficiency more important, and is there an independent effect of ART initiation? In analyses grouped by combined CD4 and viral load levels, decline in FEV1 appeared more strongly associated with HIV RNA greater than 75 000 copies/ml, whereas decline in FVC appeared more strongly associated with CD4 cell counts below 100 cells/μl. Taken together, these data suggest that HIV viremia and immunodeficiency may contribute to different lung diseases. Although the predominant effect seems to be an increase in airflow obstruction over time, not all disease in HIV-infected individuals may represent COPD. Additional studies are needed with evaluation of full pulmonary function inclusive of bronchodilator testing, lung volumes, and diffusing capacity paired with chest computed tomography scans to better understand the physiology and disease processes driving the decrease in airflow (i.e., FEV1, FVC). Furthermore, whether similar declines in FEV1 and FVC will be seen in HIV-infected cohorts with a lower prevalence of injection drug use requires investigation. A final important finding of this study to highlight is the documented increase in individuals with airflow obstruction in the cohort over time. At baseline, 16% of the cohort met spirometric criteria for airflow obstruction (defined as an FEV1/FVC<70%). During follow-up, the proportion of individuals with airflow obstruction increased to 23% at last visit. Although markers of HIV disease control were associated with more rapid decline in FEV1 and FVC, the magnitude of decrement in FEV1 decline was greater. Overall, these data confirm that the burden of chronic lung disease, particularly obstructive disease, in HIV-infected populations is increasing over time. What are the implications for clinical care? The management of chronic lung diseases such as COPD in HIV-infected populations has not been well defined as there have been no large-scale trials of COPD therapies in HIV-infected individuals. COPD is a major cause of morbidity in HIV-infected patients: it is a strong risk factor for hospitalization [16], a leading cause of respiratory failure in critically ill HIV-infected patients [17], and is associated with significantly worse health-related quality of life [18]. Whether current guidelines for management of COPD and other chronic lung diseases in HIV-uninfected patients can be applied to those with HIV infection is uncertain and requires further study. Two conclusions, however, are clear: given that approximately 40–50% of HIV-infected patients smoke compared to 20% in the general population [19], smoking-related comorbidities with a long latency of onset such as COPD will become increasingly common as HIV-infected patients are aging; and increased efforts to improve smoking cessation in HIV-infected populations are urgently needed. The study by Drummond et al. [13] underscores the importance of COPD in HIV and the need for increased awareness and understanding of obstructive lung diseases in this population. Acknowledgements Conflicts of interest There are no conflicts of interest.

The silent epidemic of COPD in Africa.

Numerous studies provide evidence for the promotion of physical activity to prevent chronic diseases in healthy subjects and reduce the risk of disease progression in chronically ill patients. In addition, the level of physical activity and the resulting aerobic capacity determine the ability to actively participate in the work process. Moreover, the relation of physical activity to aerobic capacity plays a central role in the reintegration of patients after phases of sick leave. Despite the increasing number of patients in need for reintegration into the work process after diseases or medical procedures, no established reference values exist to evaluate point of time and appropriate way of return to work. Therefore, determining physical performance criteria of different occupational groups appears to be important for assessing the individual work capacity and the ability to take over tasks that are potentially physically demanding. The aim of this thesis was to objectively measure physical activity and aerobic capacity in patients with chronic obstructive pulmonary disease (COPD) (part I) as well as in healthy employees (part II) and to investigate their relationship with regard to quality of life and reintegration into employment. In a cross-sectional manner, data of 87 stable patients with COPD were analysed in part I, while 303 healthy and full-time employed adults from different occupational groups were investigated in part II. In both parts, physical activity was quantified by the SenseWear Mini armband on seven consecutive days (23 hours/day). Average daily energy expenditure, physical activity level in metabolic equivalents of task (METs), number of steps and physical activity duration at different intensities were analysed. The submaximal level of aerobic capacity was measured by the 6-minute walk test in patients with COPD, while the maximal level (VO2max) was determined with the 20-meter shuttle run test in healthy employees. Independent associations of physical activity parameters with aerobic capacity and health outcomes were examined using multiple linear regression analysis. To determine physical performance criteria of different occupational groups, the ratio between workload as measured by METs and employees’ work capacity as measured by VO2max was analysed. In patients with COPD, the number of daily steps and aerobic capacity correlated significantly with each other and were independent predictors of quality of life, whereas no relationship was found with moderate-to-high intensity activity. In contrast, in healthy employees, high-to-very high intensity activity during leisure-time was associated with high aerobic capacity. Neither daily steps nor work-related activity revealed an independent association with VO2max. The ratio of physical workload to maximum work capacity was on average one third of VO2max and increased from sedentary occupations (21%) to jobs with moderate (29%) and high (44%) physical demands. Women showed an equal absolute workload as men, but had a higher relative workload due to their lower VO2max (37% vs. 26%). Multiple linear regressions revealed that physical workload correlated positively with moderate-, high- and very high-intensity activity at work, whereas it was negatively associated with flextime, daily working hours, age and VO2max. The findings of this thesis provide evidence that the relationship between physical activity and aerobic capacity is intensity- and type-specific and varies between impaired and healthy subjects. The results emphasise the need for patients with COPD to maintain physical activity as an integral part of everyday life and to remain mobile, whereas healthy employees need to engage in sufficient high-intensity physical activity in recreation for improving VO2max. This could be explained by the fact that patients with chronic lung disease adopt a sedentary lifestyle and get used to the lower level of physical activity, while healthy subjects may require higher-intensity stimuli to achieve health benefits. Since physical activity and aerobic capacity are independent predictors of quality of life in patients with COPD, measuring activity and fitness levels should be an integral part of the assessment of patients. This may help to prevent future disease exacerbations by allowing appropriate education or treatment. Regarding the reintegration of patients after phases of sick leave, the determined gender- and job-specific physical performance criteria may help to develop future guidelines for a safe return to work. If an individual’s job profile needs to be adjusted, the present results suggest considering various personal and job-related factors for evaluating physical workload, besides VO2max. This is an important finding, since up to now work recommendations were primarily based on individuals’ aerobic capacity. An optimised reintegration process might have the potential to reduce future loss of working hours and related health care costs. With the increasing availability of big data, prescriptive analytics might in future be able to disrupt the traditional healthcare system by recommending courses of actions and showing likely outcomes based on population-derived values.