GOLD Classification of COPD: Discordance in Criteria for Symptoms and Exacerbation Risk Assessment.

The new A-B-C-D Global Initiative for Chronic Obstructive Lung Disease (GOLD) classification of severity of chronic obstructive pulmonary disease (COPD) is based on combined symptoms and exacerbation risk assessment. The assumed equivalence between dyspnoea modified Medical Research Council (mMRC) grade ≥2 and COPD Assessment Test (CAT) score ≥ 10 to identify more symptoms has been questioned. Whether the exacerbation risk assessment criteria, old GOLD spirometry staging and frequency of exacerbations, are equivalent has not been examined. We evaluated the extent of agreement between these alternative criteria and whether it improved by redefining the equivalence between mMRC grade and CAT score. CAT scores, mMRC grades of dyspnoea, frequency of exacerbations and spirometry stages were computed in 400 patients with COPD. Receiver operating characteristic curve was analysed to determine the best CAT score to identify more symptoms. CAT scores across mMRC grades and the frequency of exacerbations across spirometry stages showed substantial overlaps. The symptoms criteria gave discordant classification in 88 (22%) patients (kappa 0.62) and the exacerbation risk assessment criteria in 181 (45%) patients (kappa 0.12). A CAT score of ≥10 had 82% sensitivity but 24% specificity to identify mMRC grade ≥ 2, while a score of 17 had 98% specificity but a low sensitivity of 52% and did not improve the agreement. We conclude that symptoms and exacerbation risk assessment criteria of the new GOLD classification yield discordant group categorisations. Lack of any satisfactory equivalence between CAT score and mMRC grades implies that the former cannot be used alone. Using the higher of mMRC ≥ 2 and CAT score ≥ 17 to identify more symptoms would avoid discordant categorisation.

Concurrent sensitization to Aspergillus Fumigatus in tropical pulmonary eosinophilia.

Tropical pulmonary eosinophilia (TPE) is characterized by lung tissue and peripheral blood eosinophilia. Serum total IgE is also markedly increased in TPE. However, an association with asthma or other hypersensitivity conditions has not been described. During the diagnostic workup of three patients eventually confirmed to have TPE, hypersensitivity to the fungus, Aspergillus Fumigatus was found. However, there was no evidence of diseases of aspergillus hypersensitivity such as severe asthma with fungal sensitization (SAFS) and allergic bronchopulmonary aspergillosis (ABPA). This association however raises the possibility of a future risk of these potentially serious allergic respiratory manifestations.

Cardiac Sympathetic Dominance and Systemic Inflammation in COPD.

Cardiac autonomic dysfunction is an independent determinant of adverse outcomes in many diseases. The available literature on the relative changes in sympathetic and parasympathetic components in chronic obstructive pulmonary disease (COPD) is equivocal, the clinical and physiological correlates are poorly defined and association with markers of systemic inflammation has not been explored. As both autonomic dysfunction and systemic inflammation may contribute to cardiovascular morbidity in COPD, we hypothesized that these may be associated. Sixty three stable patients of COPD and 36 controls underwent spirometry, estimation of diffusion capacity, six-minute walk test and measurements of serum interleukin-6 (IL-6) and high-sensitivity C-Reactive protein. Cardiac autonomic activity was evaluated by standard five-minute heart rate variability (HRV) recordings to obtain time- and frequency-domain indices and the averaged heart rate. We observed that HRV indices of overall autonomic modulation, the standard deviation of time intervals between consecutive normal beats (SDNN) and total power, were greater in patients with higher levels of indices of both parasympathetic and sympathetic activity. The heart rate was significantly higher in patients indicating an overall sympathetic dominance and was inversely correlated with diffusion capacity. Serum IL-6 was inversely correlated with pNN50, an index of parasympathetic activity, and positively with LF/HF ratio, a measure of sympathetic: parasympathetic balance. None of the HRV indices was significantly correlated with physiological measures of severity. It was concluded that patients with COPD have increased cardiac autonomic modulation with sympathetic dominance. This is associated with decreased lung diffusion capacity and systemic inflammation.

Acute exacerbations of chronic obstructive pulmonary disease: causes and impacts.

Acute exacerbations of chronic obstructive pulmonary disease (AECOPD) are recognised clinically as episodes of increased breathlessness and productive cough requiring a more intensive treatment. A subset of patients with this disease is especially prone to such exacerbations. These patients are labelled as 'frequent exacerbators'. Though yet poorly characterised in terms of host characteristics, including any genetic basis, these patients are believed to represent a distinct phenotype as they have a different natural history with a more progressive disease and a poorer prognosis than those who get exacerbations infrequently. Most exacerbations appear to be associated with infective triggers, either bacterial or viral, although 'non-infective' agents, such as air pollution and other irritants may also be important. Susceptibility to exacerbations is determined by multiple factors. Several risk factors have been identified, some of which are modifiable. Chronic obstructive pulmonary disease (COPD) exacerbations are major drivers of health status and patient-centered outcomes, and are a major reason for health care utilisation including hospitalisations and intensive care admissions. These are associated with considerable morbidity and mortality, both immediate and long-term. These episodes have a negative impact on the patient and the disease including high economic burden, increased mortality, worsening of health status, limitation of activity, and aggravation of comorbidities including cardiovascular disease, osteoporosis and neuro-psychiatric complications. Exacerbations also increase the rate of progression of disease, increasing the annual decline in lung function and leading to a poorer prognosis. Evaluation of risk of exacerbations is now included as a major component of the initial assessment of a patient with COPD in addition to the traditionally used lung function parameter, forced expiratory volume in one second (FEV1). Decreasing the risk of exacerbations and their prevention is a major therapeutic goal of management in COPD.

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.

Exhaled breath condensate analysis in chronic obstructive pulmonary disease.

The increasing focus on airway inflammation in the pathogenesis of chronic obstructive pulmonary disease (COPD) has led to development and evolution of tools to measure it. Direct assessment of airway inflammation requires invasive procedures, and hence, has obvious limitations. Non-invasive methods to sample airway secretions and fluids offer exciting prospects. Analysis of exhaled breath condensate (EBC) is rapidly emerging as a novel non-invasive approach for sampling airway epithelial lining fluid and offers a convenient tool to provide biomarkers of inflammation. It has definite advantages that make it an attractive and a feasible option. It is a source of mediators and molecules that are the causes or consequences of the inflammatory process. Measurement of such markers is increasingly being explored for studying airway inflammation qualitatively and quantitatively in research studies and for potential clinical applications. These biomarkers also have the potential to develop into powerful research tools in COPD for identifying various pathways of pathogenesis of COPD that may ultimately provide specific targets for therapeutic intervention. The EBC analysis is still an evolving noninvasive method for monitoring of inflammation and oxidative stress in the airways. The limited number of studies available on EBC analysis in COPD have provided useful information although definite clinical uses are yet to be defined. Evolving technologies of genomics, proteomics, and metabonomics may provide deeper and newer insights into the molecular mechanisms underlying the pathogenesis of COPD.

Gender differences in perception of dyspnea, assessment of control, and quality of life in asthma.

BACKGROUND: There is limited information on the inter-relationship between gender, perception of dyspnoea and health-related quality of life (HRQoL) in asthma. METHODS: In a cross-sectional study in an out-patient setting, 85 patients with bronchial asthma, 41 males and 44 females, underwent spirometry and were administered the following instruments to measure asthma control, HRQoL and dyspnoea : (a) Asthma control questionnaire (ACQ), (b) Asthma Quality of Life questionnaire (AQLQ), (c) Baseline dyspnoea index (BDI) questionnaire and Oxygen Cost Diagram (OCD). RESULTS: Overall, male patients had greater airways obstruction but reported similar level of asthma control as females. Among patients with mild persistent asthma, females had a poorer level of control. The BDI and the OCD scores were significantly lower in female patients indicating greater dyspnoea and they also had a poorer quality of life especially in the symptoms and emotional domains of the AQLQ. After adjusting for the severity of airways obstruction in multivariate analysis, female gender and a poorer quality of life were independent predictors of increased perception of dyspnoea. CONCLUSIONS: Female patients with asthma are likely to have a greater perception of dyspnoea, report a poorer control and have a poorer quality of life as compared to males. Female gender and a poorer quality of life are independent predictors of increased perception of dyspnoea in asthmatics.

Pulmonary hypertension associated with chronic obstructive pulmonary disease.

Pulmonary hypertension (PH) is likely to complicate chronic obstructive pulmonary disease (COPD) in a large proportion of patients, especially those with severe disease. Majority of patients have a mild to moderate elevation in the pulmonary artery pressure that usually does not require specific treatment. A small subset of patients, however, develops severe PH that is "out-of-proportion" to the severity of COPD. Generally considered a consequence of chronic hypoxaemia, endothelial dysfunction has now been recognised to play an important role in the pathogenesis of PH in COPD. Pulmonary vessels remodelling characterised by intimal enlargement with proliferating smooth muscle cells, medial hypertrophy, arteriolar muscularisation and endothelial cell proliferation, especially affecting the small arterioles and arteries, leads to permanent changes in the vascular structure and function. Clinical recognition of PH is difficult. Echocardiography is used for screening while right heart catheterisation is the gold standard for diagnosis. In patients who have a moderate degree of chronic hypoxaemia, long term oxygen therapy is indicated and is the only therapeutic measure so far known to retard the progress of PH. Newer therapies targeting the specific abnormalities of vasoconstrictor-vasodilator balance, arising as a consequence of endothelial dysfunction, are under investigation and may offer a management option especially in severe PH associated with COPD.

Coexistent chronic obstructive pulmonary disease-heart failure: mechanisms, diagnostic and therapeutic dilemmas.

Mortality in chronic obstructive pulmonary disease (COPD) is more often due to cardiac rather than respiratory causes. The coexistence of heart failure (HF) and COPD is frequent but remains under-diagnosed. Both conditions share several similarities including the age of the population affected, a common risk factor in smoking and symptoms of exertional dyspnoea. There is also a strong possibility of COPD promoting atherosclerotic vascular disease through systemic inflammation. Both the conditions are punctuated by episodes of acute exacerbations of symptoms from time to time where differentiation between these two can be especially challenging. Although coexistence of the two is common, more often, only one of the two is diagnosed resulting in under-treatment and unsatisfactory response. Awareness of co-occurrence is essential among both pulmonologists and cardiologists and a high index of suspicion should be maintained. The coexistence of the COPD and HF also poses several challenges in management. Active search for the second disease using clinical examination supplemented with specialised investigations including plasma natriuretic peptides, lung function testing and echocardiography should be carried out followed by appropriate management. Issues such as adverse effects of drugs on cardiac or pulmonary function need to be sorted out by studies in coexistent COPD-HF patients. Caution is advised with use of beta2-agonists in COPD when HF is also present, more so in acute exacerbations. On current evidence, the beneficial effects of selective beta1-blockers should not be denied in stable patients who have coexistent COPD-HF. The prognosis of coexistent COPD and HF is poorer than that in either disease alone. A favourable response in the patient with coexistent COPD and HF depends on proper evaluation of the severity of each of the two and appropriate management with judicious use of medication.

Role of Mycoplasma pneumoniae infection in acute exacerbations of chronic obstructive pulmonary disease.

Eighty per cent of the cases of acute exacerbation of chronic obstructive pulmonary disease (AECOPD) have an infective aetiology, atypical bacteria including Mycoplasma pneumoniae accounting for 5-10 % of these. However, the importance of association of M. pneumoniae with episodes of AECOPD still remains doubtful. The present study was therefore undertaken to delineate the extent of involvement of M. pneumoniae in patients with AECOPD at a referral hospital in Delhi, India. Sputum samples and throat swabs from a total of 100 AECOPD patients attending the Clinical Research Center of Vallabhbhai Patel Chest Institute, Delhi, were collected during a 2-year period (January 2004-June 2006). The samples were investigated for the presence of aerobic bacterial pathogens and M. pneumoniae. Diagnosis of infection with M. pneumoniae was based on culture, serology, direct detection of M. pneumoniae specific antigen and PCR. Bacterial aetiology could be established in 16 of the 100 samples studied. Pseudomonas spp. were recovered from eight cases, Streptococcus pneumoniae from four and Klebsiella spp. from two cases. Acinetobacter sp. and Moraxella catarrhalis were isolated from one case each. Serological evidence of M. pneumoniae infection and/or detection of M. pneumoniae specific antigen were seen in 16 % of the cases. One case with definite evidence of M. pneumoniae infection also had coinfection with Pseudomonas spp. However, no direct evidence of M. pneumoniae infection was found in our study population as defined by culture isolation or PCR. In conclusion, although the serological prevalence of M. pneumoniae infection in our study population was significantly higher than in the control group, there was no direct evidence of it playing a role in AECOPD.

Regional variations in vital capacity in adult males in India: comparison of regression equations from four regions and impact on interpretation of spirometric data.

BACKGROUND: Information on variations in vital capacity predicted from various regional equations for adult males in India and on their impact on interpretation of spirometric data is not available. MATERIAL AND METHODS: In a retrospective study, spirometry data of 1672 male patients, aged 15 years and above were studied. Predicted values of forced vital capacity (FVC), labelled as FVC(North), FVC(East), FVC(West) and FVC(South) were calculated from the available regional prediction equations. A prediction equation for FVC for south Indian adults above 40 years of age is not available. Spirometry data was interpreted using these and the extent of agreement between pairs of equations in detection of pattern of abnormality was analysed. RESULTS: The FVC(North) and FVC(East) were close and greater than FVC(West) and FVC(South), which were in turn, close to each other. Up to the age of 40 years, the FVC(North) exceeded FVC(East), FVC(West) and FVC(South) by 2.4%, 11.8% and 13.3%, respectively, while in the above 40 years age group, it exceeded FVC(East) and FVC(West) by 5.1% and 9.67%, respectively. The differences, however, decreased substantially with increasing FVCs and even reversed at higher values with FVC(East) tending to exceed FVC(North) in both the age groups, and FVC(West) tending to exceed FVC(North) in the above 40 years age group. While northern and eastern, and, western and southern equations gave acceptable differences (less than 5%) in interpretation of abnormality in spirometric data in patients up to 40 years of age, differences between other pairs of equations in this age group, and between all pairs in the above 40 years age group were large and unacceptable. CONCLUSIONS: Substantial variations exist in vital capacity predicted from various regional equations in adult males in India. In general, northern and eastern equations, and, western and southern equations yield closer values. While the northern Indian equation gives the highest predicted vital capacity, this is true only for lower values of vital capacities and at higher values, this may be less than that predicted from eastern or western equations. The regional differences may result in unacceptable errors in interpretation of spirometry data, if inappropriate prediction equations are used.

Distribution and determinants of body mass index of non-smoking adults in Delhi, India.

Data on height and weight of 3,428 non-smoking healthy adult subjects, obtained during an earlier community-based study in Delhi, India, on chronic respiratory morbidity due to ambient air pollution was analyzed to study the distribution of body mass index (BMI) and its determinants among adults in Delhi. The sample was drawn by systematic sampling from rural and urban areas of Delhi. In urban areas, the sampling frame was restricted to areas around air quality-monitoring stations. However, the areas were spread across the city and reflected wide economic spectrum. Subjects were classified as underweight, normal, overweight, and obese as per the criteria of the World Health Organization for BMI. The mean BMI of the entire sample was 22.14 +/- 4.61. It was higher among females, urban residents, and the higher-income group. Overall, 49.7% of the 3,428 subjects had a normal nutritional status, 24.8% were underweight, 19.4% overweight, and 6.1% obese. The prevalence of underweight was higher in rural areas (38.5%) and among the lower-income group (39.9%), while overweight and obesity were more common in urban residents (22.7% and 7.5% respectively), among females (21.7% and 7.7%), and the higher-income group (31.8% and 11%) (p < 0.05). The adjusted odds for underweight were 2.02 for rural subjects and 4.00 for the lower-income group. For overweight or obesity, odds were 5.6 for the higher-income group, 3.62 for urban residents, and 2.5 for females. It was concluded that problems of both underweight and overweight and obesity exist among the adults of Delhi. While females, residents of urban areas, and economically-better-off were more likely to be overweight or obese, residents of rural areas and those from lower-income groups were more likely to be underweight.

Platypnea-orthodeoxia syndrome in idiopathic pulmonary fibrosis with Pneumocystis jiroveci pneumonia.

Platypnea-orthodeoxia syndrome (POS), the occurrence of dyspnea and arterial desaturation on changing from supine to sitting position, is a very rare phenomenon. Most case reports have been in association with an intra-atrial communication, and observation of this unusual physiological abnormality in pulmonary conditions has been extremely rare. We present a case of idiopathic pulmonary fibrosis where the patient developed characteristic symptoms of POS when it was complicated by Pneumocystis jiroveci pneumonia. This was objectively confirmed. A similar association has not been reported earlier in literature.

Sequential occurrence of combined pulmonary fibrosis and emphysema syndrome in a non-smoker female patient.

The combined pulmonary fibrosis and emphysema (CPFE) syndrome is a unique and an under-recognized disorder characterized by emphysema in the upper lobes and interstitial fibrosis in the lower lobes of the lung. It occurs predominantly in males and almost exclusively in smokers. This rare combination of a restrictive and an obstructive mechanical defect carries a poorer prognosis than either of the two components. We present a case of CPFE syndrome in a non-smoker female patient who developed lower lobe emphysema subsequent to development of interstitial fibrosis. The case was remarkable for the extreme rarity of several presenting features, namely, a lower lobe occurrence of emphysema subsequent to pre-existent interstitial fibrosis, female gender and absence of a history of smoking.

Tropical pulmonary eosinophilia: effect of addition of corticosteroids after failure of diethylcarbamazine therapy.

Successful response in diethylcarbamazine (DEC) therapy in tropical pulmonary eosinophilia (TPE) is not universal with a 20-40% failure rates in chronic cases. Corticosteroids have been used in such patients. However, their role in management remains ill-defined. A patient of TPE with incomplete clinical, haematological and physiological response to a standard 3 weeks DEC therapy received additional corticosteroids for the next two cycles, after which complete remission occurred. However, there was a relapse two months later with evidence of a chronic state requiring further treatment with corticosteroids with good response.

Similar virulence properties of infection and colonization associated Pseudomonas aeruginosa.

PURPOSE: Pseudomonas aeruginosa is one of the agents that are commonly implicated in nosocomial infections. However, it is also present as a commensal in various body sites of healthy persons, making the diagnosis of infection by culture difficult. A number of virulence factors expressed by the organism have been implicated in its pathogenicity. We undertook this study to identify the host and organism factors associated with infection. METHODOLOGY: Pathogenic, colonizing and environmental isolates were tested for apr, lasB, the T3SS effector exoenzymes (exoS, exoT, exoU and exoY) and toxA genes, biofilm production and antimicrobial susceptibility. The isolates were further typed by RAPD. RESULTS: Eighty-seven isolates from 61 patients, including 11 environmental isolates, were obtained. None of the virulence factors were found to be significantly associated with infection, and nor was the antimicrobial susceptibility. The presence of the exoU gene and infection by MDR strains correlated significantly with the duration of hospital stay. Positivity for exoS and exoU genes was found to be strongly correlated with multi-drug resistance. exoU positivity correlated strongly with fluoroquinolone resistance. Sinks in the ward and intensive care unit were found to be a niche for XDR P. aeruginosa. Eighty-five isolates were typeable using the ERIC2 primer, showing 71 distinct RAPD patterns with >15 % difference in UPGMA-generated dice coefficients. CONCLUSIONS: exoU positivity is associated with severe disease, as evidenced by the longer duration of hospital stay of these patients. However, the presence of virulence factors or multi-drug resistance in the cultured strain should not prompt the administration of anti-pseudomonal chemotherapy.

An Improved 2-Dimensional Gel Electrophoresis Method for Resolving Human Erythrocyte Membrane Proteins.

The 2-dimensional gel electrophoresis (2-DE) technique is widely used for the analysis of complex protein mixtures extracted from biological samples. It is one of the most commonly used analytical techniques in proteomics to study qualitative and quantitative protein changes between different states of a cell or an organism (eg, healthy and diseased), conditionally expressed proteins, posttranslational modifications, and so on. The 2-DE technique is used for its unparalleled ability to separate thousands of proteins simultaneously. The resolution of the proteins by 2-DE largely depends on the quality of sample prepared during protein extraction which increases results in terms of reproducibility and minimizes protein modifications that may result in artifactual spots on 2-DE gels. The buffer used for the extraction and solubilization of proteins influences the quality and reproducibility of the resolution of proteins on 2-DE gel. The purification by cleanup kit is another powerful process to prevent horizontal streaking which occurs during isoelectric focusing due to the presence of contaminants such as salts, lipids, nucleic acids, and detergents. Erythrocyte membrane proteins serve as prototypes for multifunctional proteins in various erythroid and nonerythroid cells. In this study, we therefore optimized the selected major conditions of 2-DE for resolving various proteins of human erythrocyte membrane. The modification included the optimization of conditions for sample preparation, cleanup of protein sample, isoelectric focusing, equilibration, and storage of immobilized pH gradient strips, which were further carefully examined to achieve optimum conditions for improving the quality of protein spots on 2-DE gels. The present improved 2-DE analysis method enabled better detection of protein spots with higher quality and reproducibility. Therefore, the conditions established in this study may be used for the 2-DE analysis of erythrocyte membrane proteins for different diseases, which may help to identify the proteins that may serve as markers for diagnostics as well as targets for development of new therapeutic potential.

Prediction Equations for Spirometry for Children from Northern India.

OBJECTIVE: To develop prediction equations for spirometry for children from northern India using current international guidelines for standardization. DESIGN: Re-analysis of cross-sectional data from a single school. PARTICIPANTS: 670 normal children (age 6-17 y; 365 boys) of northern Indian parentage. METHODS: After screening for normal health, we carried out spirometry with recommended quality assurance according to current guidelines. We developed linear and nonlinear prediction equations using multiple regression analysis. We selected the final models on the basis of the highest coefficient of multiple determination (R2) and statistical validity. MAIN OUTCOME MEASURES: Spirometry parameters: FVC, FEV1, PEFR, FEF50, FEF75 and FEF25-75. RESULTS: The equations for the main parameters were as follows: Boys, Ln FVC = -1.687+0.016*height +0.022*age; Ln FEV1 = -1.748+0.015*height+0.031*age. Girls, Ln FVC = -9.989 +(2.018*Ln(height)) + (0.324*Ln(age)); Ln FEV1 = -10.055 +(1.990*Ln(height))+(0.358*Ln(age)). Nonlinear regression yielded substantially greater R2 values compared to linear models except for FEF50 for girls. Height and age were found to be the significant explanatory variables for all parameters on multiple regression with weight making no significant contribution. CONCLUSION: We developed prediction equations for spirometry for children from northern India. Nonlinear equations were superior to linear equations.

Occupational bronchiolitis induced by cotton dust exposure in a nonsmoker.

The most well-known disease caused by cotton dust is byssinosis though it is also associated with chronic obstructive airways disease, and very rarely, interstitial lung disease. Obliterative bronchiolitis has never been reported in this setting. We report a 63-year-old, nonsmoker male, who presented with complaints of cough and exertional dyspnoea for 10 years. He had worked in textile industry for 35 years and symptoms had persisted even after quitting. Examination revealed prolonged expiration with expiratory wheeze, and pulmonary function tests revealed severe airflow limitation with air trapping and impaired diffusion capacity. Arterial blood gas analysis showed type I respiratory failure. A high resolution computed tomogram of the chest showed bilateral centrilobular nodules with tree-in-bud pattern and areas of air trapping. A diagnosis of obliterative bronchiolitis induced by cotton dust exposure was established on the basis of the occupational history and the characteristic radiological signs.

Challenges in Collating Spirometry Reference Data for South-Asian Children: An Observational Study.

METHODS: Spirometry datasets from South-Asian children were collated from four centres in India and five within the UK. Records with transcription errors, missing values for height or spirometry, and implausible values were excluded(n = 110). RESULTS: Following exclusions, cross-sectional data were available from 8,124 children (56.3% male; 5-17 years). When compared with GLI-predicted values from White Europeans, forced expired volume in 1s (FEV1) and forced vital capacity (FVC) in South-Asian children were on average 15% lower, ranging from 4-19% between centres. By contrast, proportional reductions in FEV1 and FVC within all but two datasets meant that the FEV1/FVC ratio remained independent of ethnicity. The 'GLI-Other' equation fitted data from North India reasonably well while 'GLI-Black' equations provided a better approximation for South-Asian data than the 'GLI-White' equation. However, marked discrepancies in the mean lung function z-scores between centres especially when examined according to socio-economic conditions precluded derivation of a single South-Asian GLI-adjustment. CONCLUSION: Until improved and more robust prediction equations can be derived, we recommend the use of 'GLI-Black' equations for interpreting most South-Asian data, although 'GLI-Other' may be more appropriate for North Indian data. Prospective data collection using standardised protocols to explore potential sources of variation due to socio-economic circumstances, secular changes in growth/predictors of lung function and ethnicities within the South-Asian classification are urgently required.