Atopy in people aged 40 years and over: Relation to airflow limitation

BACKGROUND

Previous studies have reached conflicting conclusions about the role of atopy as a risk factor for COPD. In part, this is attributable to variation in the definitions of airflow limitation and the treatment of people with asthma.

OBJECTIVE

To establish whether there is any independent association between atopy and post-bronchodilator airflow limitation in the general population aged 40 years and over.

METHODS

A cross-sectional survey was conducted in a general population sample of 2415 people aged 40 years and over in Australia. A history of ever being diagnosed with asthma was elicited by questionnaire. Atopy was defined as any skin prick test weal to common aeroallergens ≥4 mm. Airflow limitation was defined as post-bronchodilator spirometric (FEV₁ /FVC) ratio <lower limit of normal. Analyses were adjusted for potential confounding due to age, sex, smoking, race and socio-economic status.

RESULTS

The prevalence of atopy, ever diagnosed asthma and post-bronchodilator airflow obstruction was 44.8%, 19.3% and 7.5%, respectively. In the population as a whole, atopy was associated with lower FEV₁ (adjusted difference -0.068L, 95% confidence interval (CI) -0.104 to -0.032), FVC (adj. difference -0.043L, 95% CI -0.086 to -0.0009) and post-bronchodilator FEV₁/FVC ratio (adj. difference -0.011, 95% CI -0.017 to -0.0055). The effect of atopy on lung function was no longer apparent when participants who reported ever diagnosed asthma were excluded (FEV₁ -0.011L, [95% CI -0.05 to 0.028L], FVC -0.012L [95% CI -0.060 to 0.036] and FEV₁/FVC ratio -0.0012 [95% CI -0.0072 to 0.0047L]).

CONCLUSION AND CLINICAL RELEVANCE

The apparent association between atopy and post-bronchodilator airflow limitation in the general population appears to be explained by the association between atopy and having ever diagnosed asthma and the effect of asthma on lung function.

An observational study of PM10 and hospital admissions for acute exacerbations of chronic respiratory disease in Tasmania, Australia 1992-2002

Objective

Particulate matter with a diameter below 10 µ (PM₁₀) has been a major concern in the Tamar Valley, Launceston, where wood heaters are extensively used. We examined the relationship between PM₁₀ levels, meteorological variables, respiratory medications and hospital admissions for respiratory disease over the decade 1992–2002.

Methods

PM₁₀ levels were provided by the Department of Primary Industry Water, Parks and Environment, and meteorological variables from the Bureau of Meteorology. We obtained hospital discharge codes for the Launceston General Hospital. Poisson regression was used for statistical analyses.

Results

Mean daily PM₁₀ levels declined from 50.7 to 16.5 μg/m³. Hospitalisations for asthma decreased from 29 to 21 per month, whereas chronic obstructive pulmonary disease (COPD) increased and bronchitis/bronchiolitis remained unchanged. We found a 10 μg/m³ increase in PM₁₀ to be associated with a 4% increase in admissions for acute bronchitis/bronchiolitis (p0.05), but no association with asthma or COPD was found. All respiratory diseases showed seasonal patterns of hospitalisation.

Conclusions

This is the first long-term study in Australia to demonstrate an association between PM₁₀ levels and respiratory diseases. Reducing exposure to PM₁₀ may decrease hospital admissions for respiratory diseases.

Implication

Better preventive measures, including sustained public health initiatives to combat air pollution, are required to reduce respiratory morbidity.

Cardiovascular effects of methacholine-induced airway obstruction in man

Cardiovascular disease is the most frequent cause of death in people with chronic respiratory disease. The cause of this association has been attributed to airway obstruction leading to cardiovascular dysfunction (increased central blood pressure (BP) and aortic stiffness). However, this has never been experimentally tested. Methacholine is routinely used to stimulate airway function changes that mimic airway pathology. This study aimed to determine the cardiovascular effects of methacholine-induced airway obstruction. Fifteen healthy young adults (aged 22.9±2.5 years; 4 male; mean±S.D.) underwent a bronchial challenge test (randomized, blinded, cross-over design) in which they received nebulized methacholine inhalation in serially increasing concentrations (from 0.39 to 25 mg/ml) or saline (0.9%; control) on two separate days. Bronchoconstriction was assessed by forced expiratory volume at one second (FEV1) and cardiovascular effects by augmentation index, brachial BP, central BP, heart rate and aortic stiffness. Methacholine significantly decreased FEV1 from baseline to peak inhaled concentration compared with saline (-0.48±0.34 vs. -0.07±0.16 L; p<0.001), but there was no between-group change in augmentation index (1.6±7.0 vs. 3.7±10.2% p=0.49), brachial systolic BP (-3.3±7.6 vs. -4.7±5.7 mmHg; p=0.59), central systolic BP (-1.1±5.2 vs. -0.3±5.5 mmHg; p=0.73), heart rate (0.4±7.1 vs. -0.8±6.6 bpm; p=0.45) or aortic stiffness (0.2±1.3 vs. 0.8±1.8 m/s; p=0.20; n=12). Thus, methacholine induced airway obstruction does not acutely change brachial BP or central haemodynamics. This finding refutes the notion that airway obstruction per se leads to cardiovascular dysfunction, at least in healthy individuals in the acute setting.

Interstitial lung disease due to fumes from heat-cutting polymer rope

Interstitial lung disease (ILD) due to inhalation of fume/smoke from heating or burning of synthetic polymers has not been reported previously. A fish farm worker developed ILD after cutting rope (polypropylene and nylon) for about 2 hours per day over an extended period using an electrically heated 'knife'. This process produced fume/smoke that entered the workers breathing zone. No other likely cause was identified. This case suggests that exposure to airborne contaminants generated by the heating or burning of synthetic polymers has the potential to cause serious lung disease.

Adherence to asthma management guidelines by middle-aged adults with current asthma

BACKGROUND

With the increasing burden of asthma worldwide, much effort has been given to developing and updating management guidelines. Using data from the Tasmanian Longitudinal Health Study (TAHS), the adequacy of asthma management for middle-aged adults with asthma was investigated.

METHODS

Information about spirometry, medication history and current asthma status was collected by the most recent TAHS when participants were in their mid 40s. Only those who reported ever having asthma were eligible for analysis.

RESULTS

Of the 702 participants who reported ever having asthma, 50% had current asthma (n = 351) of whom 71% were categorised as having persistent asthma (n = 98 mild, n = 92 moderate, n = 58 severe). The majority (85.2%) of participants with current asthma had used some form of asthma medication in the past 12 months, but the proportion of the use of minimally adequate preventer medication was low (26%). Post-bronchodilator airflow obstruction increased progressively from mild to severe persistent asthma for those inadequately managed, but not for those on adequate therapy.

CONCLUSION

Appropriate use of asthma medication by this middle-aged group of adults with current asthma was inadequate, especially for those with adult-onset moderate or severe persistent disease and without a family history of asthma. These results suggest that proper use of preventer medication could protect against the progressive decline in lung function associated with increasing severity. This has implications not just for poor quality of life, but also for the development of fixed airflow obstruction.

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.

Airway cell and cytokine changes in early asthma deterioration after inhaled corticosteroid reduction

BACKGROUND

Back-titration of inhaled corticosteroid (ICS) dose in well-controlled asthma patients is emphasized in clinical guidelines, but there are few published data on the airway cell and cytokine changes in relation to ICS reduction. In our study, 20 mild-to-moderate persistent (inspite of low-moderate dose ICS treatment) asthmatic subjects prospectively rendered largely asymptomatic by high-dose ICS were assessed again by clinical, physiological, and airway inflammatory indices after 4-8 weeks of reduced ICS treatment. We aimed at assessing the underlying pathological changes in relation to clinical deterioration.

METHODS

Patients recorded daily symptom scores and peak expiratory flows (PEF). Spirometry and airways hyperreactivity (AHR) were measured and bronchoscopy was performed with assessment of airway biopsies (mast cells, eosinophils, neutrophils, and T lymphocytes), bronchoalveolar lavage (BAL) IL-5 and eotaxin levels and cellular profiles at the end of high-dose ICS therapy and again after ICS dose reduction. Baseline data were compared with symptomatic steroid-free asthmatics (n=42) and non-asthmatic controls (n=28).

RESULTS

After ICS reduction, subjects experienced a variable but overall significant increase in symptoms and reductions in PEF and forced expiratory volume in 1 s. There were no corresponding changes in AHR or airways eosinophilia. The most relevant pathogenic changes were increased CD4(+)/CD8(+) T cell ratio, and decreased sICAM-1 and CD18 macrophage staining (potentially indicating ligand binding). However, there was no relationship between the spectrum of clinical deterioration and the changes in cellular profiles or BAL cytokines.

CONCLUSIONS

These data suggest that clinical markers remain the most sensitive measures of early deterioration in asthma during back-titration of ICS, occurring at a time when AHR and conventional indices of asthmatic airway inflammation appear unchanged. These findings have major relevance to management and to how back-titration of ICS therapy is monitored.

Injectable vaccines for preventing pneumococcal infection in patients with chronic obstructive pulmonary disease

BACKGROUND

As chronic obstructive pulmonary disease (COPD) progresses, exacerbations can occur with increasing frequency. One goal of therapy in COPD is to try and prevent these exacerbations, thereby reducing disease morbidity and associated healthcare costs. Pneumococcal vaccinations are considered to be one strategy for reducing the risk of infective exacerbations.

OBJECTIVES

To determine the safety and efficacy of pneumococcal vaccination in COPD. The primary outcome assessed was acute exacerbations. Secondary outcomes of interest included episodes of pneumonia, hospital admissions, adverse events related to treatment, disability, change in lung function, mortality, and cost effectiveness.

SEARCH STRATEGY

We searched the Cochrane Airways Group COPD trials register using pre-specified terms. We also conducted additional handsearches of conference abstracts. The last round of searches were performed in April 2006.

SELECTION CRITERIA

Only randomised controlled trials assessing the effects of injectable pneumococcal vaccine in people with COPD were included.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data and three review authors independently assessed trial quality.

MAIN RESULTS

Although 10 studies cited in 11 publications were identified that met the inclusion criteria for this review, only four of these provided data on participants with COPD. The studies which did provide data for this review consisted of two trials using a 14-valent vaccine, and two using a 23-valent injectable vaccine. Data for the primary outcome, acute exacerbation of COPD, was available from only one of the four studies. The odds ratio of 1.43 (95% confidence interval (CI) 0.31 to 6.69) between interventions was not statistically significant. Of the secondary outcomes for which data were available and could be extracted, none reached statistical significance. Three studies provided dichotomous data for persons who developed pneumonia (OR 0.89, 95% CI 0.58 to 1.37, n = 748). Rates of hospital admissions and emergency department visits came from a single study. There was no significant reduction in the odds of all-cause mortality 1 to 48 months post-vaccination (Peto odds ratio 0.94, 95% CI 0.67 to 1.33, n = 888), or for death from cardiorespiratory causes (OR 1.07, 95% CI 0.69 to 1.66).

AUTHORS' CONCLUSIONS

There is no evidence from randomised controlled trials that injectable pneumococcal vaccination in persons with COPD has a significant impact on morbidity or mortality. Further large randomised controlled trials would be needed to ascertain if the small benefits suggested by individual studies are real.

Oxygen therapy in the pre-hospital setting for acute exacerbations of chronic obstructive pulmonary disease

BACKGROUND

Chronic obstructive pulmonary disease (COPD), a leading cause of morbidity and mortality in the developed world, is characterised by acute deterioration in symptoms. During these exacerbations, people are prone to developing alveolar hypoventilation, which may be contributed to by the administration of high inspired oxygen concentrations.

OBJECTIVES

The objective of the review was to determine the effect of different inspired oxygen concentrations ("high flow" compared to "controlled") in the pre-hospital setting on outcome for people with acute exacerbations of COPD.

SEARCH STRATEGY

We searched the Cochrane Airways Group Specialised Register (August 2005), the Cochrane Central Register of Controlled Trials (The Cochrane Library Issue 3, 2005), MEDLINE (1966 to August 2005), EMBASE (1980 to wk 32, 2005), CINAHL (1982 to August wk 1, 2005) and reference lists of articles. We also contacted authors of identified RCTs for details of other relevant, published and unpublished studies.

SELECTION CRITERIA

Randomised controlled trials comparing oxygen therapy at different concentrations or oxygen therapy versus placebo in the pre-hospital setting for treatment of acute exacerbations of COPD were eligible.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial quality and extracted data.

MAIN RESULTS

The search identified a total of 741 abstracts, of which 18 were selected as potentially relevant, only two of the 18 studies were randomised controlled trials and eligible for inclusion in the review, but were ongoing and had no data available for analysis.

AUTHORS' CONCLUSIONS

No relevant trials have been published to date, so there is no evidence to indicate whether different oxygen therapies in the pre-hospital setting have an effect on outcome for people with acute exacerbations of COPD. There is an urgent need for robust, well-designed randomised controlled trials to investigate the effect of oxygen therapies in the pre-hospital setting for people with acute exacerbations of COPD.

Prognostic significance of immunohistochemical markers in non-small cell lung cancer

7211

Background: The purpose of this study is to use a large patient population to identify immunohistochemical (IHC) biomarkers to enable improved prognostication in patients with non-small cell lung cancer (NSCLC). Methods: A tissue microarray was constructed using duplicate 0.6 mm cores of formalin-fixed paraffin embedded tissue blocks from 609 patients with NSCLC. IHC was used to detect 11 biomarkers including EGFR, HER2, HER3, p53, p63, Bcl-1, Bcl-2, TTF-1, CEA, Ch, and SNP. A clinical database was created prospectively at the time of tissue collection. Survival outcomes were obtained from a Provincial Cancer Registry database. Results: Male to female ratio was 400:209; median age 63yrs (range 35–82); median survival 3.5yrs (mean 5.7). All specimens were reviewed: 243 adenocarcinoma (ACA), 272 squamous cell carcinoma (SCC), 35 large cell carcinoma, 32 non-small cell carcinoma NOS, and 6 other (giant cell carcinoma). 21 patients with other histologies were excluded. Survival data for 535 cases was available. As of June 2005, 429 patients (80%) had died; of these 286 (54%) died of lung cancer, 117 (22%) died of other known causes, and for 26 (5%) the cause of death was not available. Bcl-2 (p = 0.007) was the only biomarker to predict better overall survival (OS). Bcl-2 (p = 0.021) and p63 (p = 0.025) were significant for disease specific survival (DSS) in all NSCLC. Analysis of the subgroups indicated that p63 was significant (p = 0.039) for DSS in squamous cell carcinoma (SCC) but not for adenocarcinoma (ACA) (p = 0.81). Bcl-2 was not significant for DSS in either subgroup (p = 0.28 for SCC, p = 0.112 for ACA). EGFR expression was associated with improved DSS in SCC (p = 0.012) but not for ACA. Co-expression of EGFR-HER3 was more likely in SCC then in ACA (p = 0.033). There was no correlation between outcome and any combination or clustering of biomarkers. Conclusions: The biomarkers p63 and Bcl-2 are predictive of DSS in NSCLC. EGFR expression is predictive of DSS in SCC. Sub-classification of NSCLC by histopathology is important as the relevance of some biomarkers (EGFR) would be lost if pooled. p63, Bcl-2, and EGFR may be used as prognostic markers in patients with NSCLC. Co-expression of EGFR-HER3 is more likely in SCC then in ACA. This may help explain the differential response to EGFR inhibitors in SCC versus ACA.

No significant financial relationships to disclose.

Action plans for chronic obstructive pulmonary disease

BACKGROUND

The effectiveness of action plans as treatment for chronic obstructive pulmonary disease (COPD) is not known.

OBJECTIVES

To assess the efficacy of action plans in the management of COPD.

SEARCH STRATEGY

We searched the Cochrane Airways Group Specialised Register, CENTRAL, MEDLINE, CINAHL and the National Research Register of Ongoing Trials. We also searched reference lists of identified studies. The search was completed in August 2004.

SELECTION CRITERIA

Randomised controlled trials of action plans in COPD. Studies with a primary diagnosis of asthma excluded.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed trial quality and extracted data. Investigators were contacted for additional information when necessary. Study results were combined in meta-analyses using the Cochrane Collaboration software RevMan.

MAIN RESULTS

There was evidence of a positive effect of action plans on self-management knowledge. The mean difference (MD) for recognition of a severe exacerbation was 2.50; 95% confidence interval 1.04 to 3.96, for self-action in severe exacerbations MD 1.50; 95% confidence interval 0.62 to 2.38 and the use of antibiotics MD 6.00; 95% confidence interval 2.68 to 9.32. There was also evidence of a positive effect on the initiation of antibiotics (odds ratio (OR) 10.16; 95% confidence interval 2.02 to 51.09) and/or oral steroids (OR 6.58; 95% confidence interval 1.29 to 33.62). However, there was no evidence of significant effects on healthcare utilisation, health-related quality of life, lung function, functional capacity, symptom scores, mortality, anxiety, or depression. No trials used as outcomes: number of exacerbations, length of exacerbations, or days lost from work.

AUTHORS' CONCLUSIONS

This review shows there is evidence that action plans aid people with COPD in recognising and reacting appropriately to an exacerbation of their symptoms via the self-initiation of antibiotics or steroids. Further research needs to be completed with more comprehensive outcomes measures in order to ascertain whether this results in significantly decreased morbidity and/or mortality.

Oral corticosteroids for stable chronic obstructive pulmonary disease

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is a common chronic lung disorder, usually related to cigarette smoking, representing a major and increasing cause of morbidity and mortality. It is defined "as a disease state characterized by airflow limitation that is not fully reversible. The airflow limitation is usually both progressive and associated with an abnormal inflammatory response of the lungs to noxious particles or gases". The use of corticosteroids for their anti-inflammatory effects has been suggested.

OBJECTIVES

To assess the effects of oral corticosteroids on the health status of patients with stable COPD.

SEARCH STRATEGY

Searches of the Cochrane Airways Group Specialised Register and MEDLINE were carried out in December 2003 and 2004. Review articles and bibliographies were searched.

SELECTION CRITERIA

Randomised controlled prospective studies in adults with stable COPD ( post-bronchodilator FEV1 <80% of predicted, FEV1/FVC <70%) and a history of smoking, excluding known asthmatics, in which oral steroid use was compared with placebo and use of co-interventions was matched in both groups.

DATA COLLECTION AND ANALYSIS

Data was extracted independently by two reviewers. All trials were combined using Review Manager (version 4.2.7).

MAIN RESULTS

From 459 titles 24 studies met the inclusion criteria. Treatment lasted three weeks or less in 19 studies, high dose oral steroid was used in 21 studies and subjects had moderate or severe COPD in 15 studies. There was a significant difference in FEV1 after two weeks treatment, WMD 53.30 ml; 95% confidence interval 22.21 to 84.39 favouring oral steroid use compared to placebo when 14 studies with available data (n=396) were combined, with no significant heterogeneity. There was a significant increase in odds for individual patient FEV1 response greater than 20% from baseline with high dose oral steroid treatment compared to placebo, OR 2.71; 95% CI 1.84 to 4.01 (9 studies) . It would be necessary to treat 7 patients (95% CI 5 to 12) with oral corticosteroids to achieve one extra case of increasing FEV1 by more than 20%, with a placebo group risk of 0.13. All differences in health-related quality of life were less than the minimum clinically important difference. There were small statistically significant advantages for functional capacity and respiratory symptom of wheeze with oral steroid treatment but no significant difference in risk of withdrawal from study due to an exacerbation or rate of serious exacerbations over 2 years with low dose oral steroid treatment. There was an increased risk of adverse effects, including increased blood glucose, adrenal suppression and reduced serum osteocalcin.

AUTHORS' CONCLUSIONS

There is no evidence to support the long-term use of oral steroids at doses less than 10-15 mg prednisolone though some evidence that higher doses (>/= 30 mg prednisolone) improve lung function over a short period. Potentially harmful adverse effects e.g.. diabetes, hypertension, osteoporosis would prevent recommending long-term use at these high doses in most patients.

Long-acting beta2-agonists in asthma: an overview of Cochrane systematic reviews

According to major asthma management guidelines, long-acting beta2-agonists (LABAs) should be used only when asthma remains symptomatic in patients already receiving regular inhaled corticosteroids (ICSs). A large Cochrane systematic review provides evidence that LABAs are safe and beneficial in control of asthma; sub-group analyses indicating that this is true when ICSs are used and in their absence. Two other Cochrane systematic reviews have found that LABAs are more effective than regular short-acting beta2-agonists, and are as effective as theophylline with fewer side-effects. These reviews support guidelines in the use of LABA as additional therapy when asthma is inadequately controlled by ICS at moderate dose. However, guidelines may be too conservative, and more studies in stable mild asthma comparing their use and safety with placebo and ICS are required.

Decreased lung capillary blood volume post-exercise is compensated by increased membrane diffusing capacity

The diffusing capacity of the lung for carbon monoxide (DLCO) decreases to below the pre-exercise value in the hours following a bout of intense exercise. Two mechanisms have been proposed: (1) development of pulmonary oedema and (2) redistribution of central blood volume to peripheral muscles causing a reduction in pulmonary capillary blood volume ( V(c)). In the present study DLCO, V(c) and the membrane diffusing capacity ( D(m)) were measured in nine healthy females using a rebreathing method, in contrast to the single breath technique employed in previous studies. DLCO, V(c) and D(m) were measured before and at 1, 2, 3, 16 and 24 h following maximal treadmill exercise. Compared with pre-exercise values, DLCO was depressed by up to 8.9 (3.0)% ( P<0.05) for the first 3 h following exercise, but had returned to pre-exercise values by 16 h post-exercise. V(c) fell by 21.2 (4.1)% ( P<0.05) at 3 h post-exercise, but at the same time D(m) increased by 14.7 (9.1)%. It was concluded that: (1) the increase in D(m) made it unlikely that the fall in DLCO was due to interstitial oedema and injury to the blood gas barrier; (2) on the other hand, the reduction in DLCO following exercise was consistent with a redistribution of blood away from the lungs; and (3) the trend for D(m) and V(c) to reciprocate one another indicates a situation in which a fall in V(c) nevertheless promotes gas transfer at the respiratory membrane. It is suggested that this effect is brought about by the reorientation of red blood cells within the pulmonary capillaries following exercise.

(R,S)-salbutamol plasma concentrations in severe asthma

OBJECTIVE

Salbutamol is commonly delivered as a racemic mixture of pharmacologically active (R)-salbutamol and inactive (S)-salbutamol. This study investigated inactive (S)- and active (R)-salbutamol plasma levels and their relationship to dose in patients with severe asthma.

METHODS

Basic demographics, racemic-salbutamol dose in the preceding 24 h, lung function tests at baseline and 1 h, and a 10 mL plasma sample were obtained from subjects presenting to the Department of Emergency Medicine with acute asthma. Plasma determinations were carried out using an LC-MS assay with solid phase extraction.

RESULTS

All patients (n = 5) had detectable levels of drug in plasma with range of 0.9-7.7 and 4.7-27.4 ng/mL for (R)-salbutamol and (S)-salbutamol respectively. These were correlated to total racemic salbutamol dose. The range of the (S) : (R) ratio was 2.0-5.2, with (R)-salbutamol representing 16-33% of the total plasma concentration, which did not correlate with total salbutamol dose.

CONCLUSION

Only a small fraction of total plasma salbutamol concentration was found to consist of active enantiomer in patients with an acute severe exacerbation of asthma actively undergoing treatment with racemic-salbutamol. As a result of the possible contribution of (S)-salbutamol to poor asthma control further enantioselective investigations are warranted in severe asthma.

Oxatomide for stable asthma in adults and children

BACKGROUND

Oxatomide is a histamine H1-receptor antagonist. As an oral agent, oxatomide may be useful in managing asthma. Some guidelines recommend oxatomide for long-term prophylaxis of asthma in children. There is no clear evidence whether children or adults with asthma benefit from oxatomide.

OBJECTIVES

To determine whether oxatomide alone, or in combination with other interventions, results in better disease control in people with asthma.

SEARCH STRATEGY

The Collaborative Airway Group register and Collaborations trial register CENTRAL were searched using terms: oxatomide* OR Celtect OR Pinset OR KW-4354 OR Tincet. Reference lists of all relevant trials or review articles were checked. Enquiries were made of authors of included studies and relevant pharmaceutical companies. A search of 'Igaku Chuo Zasshi' and 'J-Medicine' were made using the following terms: oxatomide (also in Japanese) or Celtect (also in Japanese) or KW-4354.

SELECTION CRITERIA

Studies were randomised, placebo-controlled trials and the interventions were oxatomide or matched placebo given alone or in combination with other asthma-medication for at least 4 weeks.

DATA COLLECTION AND ANALYSIS

Four independent reviewers performed assessments of methodological quality and extracted relevant data.

MAIN RESULTS

Six studies are included in this review. Three studies were mainly conducted in adults, two were conducted in older children (5-16 years) and one in infants (18-25 months). Trial duration was 4 to 52 weeks. Doses of oxatomide varied between studies, ranging from 1 mg/kg/day for infants to 180 mg/day for adults. Only data on adverse events was suitable for meta-analysis. Although PEF did not change significantly in any of the studies, the FVC and FEV1 improved significantly in two. There was no uniform change in symptom scores. There was no significant difference between oxatomide and placebo treatment in use of inhaled corticosteroid or bronchodilator. Two studies showed significant improvement with oxatomide as judged subjectively by physicians. Adverse events, analysed using data from 4 parallel and one cross over study, showed oxatomide to be associated with a significantly higher risk of any adverse event (OR: 2.97, 95%CI: 1.69 to 5.22) and drowsiness (OR: 5.22,95%CI: 2.53 to 10.74).

REVIEWER'S CONCLUSIONS

There is no evidence to show that oxatomide has a significant effect on the control of stable asthma. Some studies reported significant benefits in subjective parameters. There was improvement in some lung function outcomes reported, but this were not consistent across measures or studies and may represent reporting bias. Adverse events, including drowsiness, were significantly greater with oxatomide than placebo.

Review of the effect of the dosing interval for inhaled corticosteroids in asthma control

BACKGROUND

Asthma is recognized as an inflammatory disease of the airways and treatment includes anti-inflammatory agents such as corticosteroids. Inhaled corticosteroids (ICS) are widely prescribed for long-term prophylaxis, yet their optimal dosing interval is not clear.

AIMS

To determine whether the dosing interval of ICS affects asthma control.

METHODS

We performed an electronic search of the literature to identify studies on the dosing interval of ICS in asthmatic subjects. Data were extracted from suitable studies by two independent researchers and, where possible, a meta-analysis performed.

RESULTS

A total of 4,267 titles were retrieved, of which 13 met inclusion and exclusion criteria and 11 had extractable data. There were no significant differences between outcomes for: (i) once daily vs twice daily administration (7 trials, 810 subjects), (ii) once daily vs four times daily administration (2 trials, 68 subjects) and (iii) twice daily vs four times daily administration (4 studies, 111 subjects). There was a variety of outcomes used to assess differences between dosing intervals. These included symptom scores, lung function, use of rescue medication and adverse drug effects. The number of subjects that could be included in the statistical analysis of any of such outcomes was small, much smaller than the total sample size.

CONCLUSIONS

There was no significant difference in measures of asthma control between the assessed dosing intervals of ICS. Current evidence indicates that single daily administration of ICS produces equivalent asthma control to multiple daily administration.

Outcome of a smoking cessation programme run in a routine hospital setting

BACKGROUND

Although tobacco smoking remains the largest preventable cause of mortality in Australia, resources to assist with cessation remain scarce. Research studies have demonstrated improved cessation rates with interventions such as counselling and pharmacotherapy, but there is little information on success in routine clinical practice.

AIMS

To determine the outcome of a smoking cessation programme run in a routine hospital outpatient setting.

METHODS

A prospective audit of patients referred to an outpatient smoking cessation programme by hospital specialists or general practitioners. The programme consisted of fortnightly counselling sessions, with nicotine replacement therapy when clinically indicated. Self-reported abstinence rates were determined by contacting patients by letter or telephone at 3 and 12 months. Abstinence was confirmed, whenever possible, by measuring the expired carbon monoxide (CO) concentration.

RESULTS

Over 12 months, 226 new patients were seen through the programme. There was a correlation between the number of cigarettes smoked and the baseline Fagerstrom score (r = 0.49, P < 0.001). Approximately 40% of subjects could not be contacted for follow up. At 3 months the self-reported abstinence rate was 31%, falling to 19% by 12 months. Measurement of expired CO concentrations proved that self-reported abstinence was reliable.

CONCLUSIONS

The abstinence rates achieved by our programme compared well with those previously reported in the literature, demonstrating the effectiveness of a smoking cessation programme run in routine clinical practice. There was an increasing relapse rate during the period of follow up.

Fibre-optic bronchoscopy in adults: a position paper of The Thoracic Society of Australia and New Zealand

Fibre-optic bronchoscopy in adults is a common procedure in clinical respiratory practice. Under controlled conditions it is safe, resulting in relatively few significant adverse events. The present position paper updates guidelines previously published by The Thoracic Society of Australia and New Zealand and is based on evidence obtained by searching the Medline and Embase databases. The level of evidence to support recommendations is indicated in the text. Where no evidence has been found, the guidelines reflect the opinions of the authors. Specific recommendations are made regarding sedation and anaesthesia, the cleaning of bronchoscopes and the training of bronchoscopists.

Corticosteroids for acute exacerbations of chronic obstructive pulmonary disease

BACKGROUND

Acute exacerbations occur quite commonly in patients with chronic obstructive pulmonary disease (COPD). Corticosteroid drugs, either parenteral or oral, are used commonly in this setting.

OBJECTIVES

To determine the effect of corticosteroids, administered either parenterally or orally, on the outcome in patients with acute exacerbations of COPD.

SEARCH STRATEGY

An initial search was carried out using the Cochrane Airways Group COPD register with additional studies sought in the bibliographies of randomised controlled trials and review articles. Authors of identified randomised controlled trials were contacted for other published and unpublished studies.

SELECTION CRITERIA

Randomised controlled trials comparing corticosteroids, administered either parenterally or orally, with appropriate placebo. Other interventions were standardised e.g. bronchodilators, antibiotics. Studies of acute asthma were excluded.

DATA COLLECTION AND ANALYSIS

Data was extracted by one reviewer and sent to authors for verification. All trials were combined for analysis where possible.

MAIN RESULTS

We identified 7 studies that fulfilled the inclusion criteria. Outcomes were varied and few were common to all studies. The most commonly reported outcome, the FEV1 between 6 - 72 hours after treatment, showed no significant difference between corticosteroid and placebo treatment. Treatment failure (defined as re-attendance in the emergency department, need for oral steroids or hospitalisation) and quality of life did show a statistically significant benefit for corticosteroid treatment, but the number of studies reporting these outcomes was small and there was significant heterogeneity between them

REVIEWER'S CONCLUSIONS

Treatment with oral or parenteral corticosteroids in outpatients may decrease the number of patients requiring further treatment or hospitalisation, but otherwise it has no significant effect on the outcome of acute exacerbations of chronic obstructive airways disease. Further research is required to determine the place of corticosteroid treatment in acute exacerbations of chronic obstructive airways disease.

Histamine and the nasal vasculature: the influence of H1 and H2-histamine receptor antagonism

The aim was to determine the effect of H1- and H2-receptor blockade on histamine-induced changes in nasal airways resistance and lavage protein concentrations. Normal subjects were pretreated with oral cetirizine or ranitidine in a double-blind and randomized manner. Measurements of the concentration of total protein and albumin in nasal lavage fluid together with nasal airway resistance were made before and after challenge. Any effect of treatment was assessed by comparing the areas under the time-response curves. In all nine subjects available for analysis histamine caused an immediate increase in all measurements. Ranitidine reduced the maximum increase in nasal airway resistance, but this effect was significant only in combination with certirizine. The increase in lavage total protein and albumin concentrations was almost completely abolished by cetirizine, whereas ranitidine had less effect. We conclude that the histamine H1-receptor has the greatest effect on changes in nasal vascular permeability induced by topical histamine, whereas the H2-receptor has the greatest effect on nasal obstruction.

Exercise-induced bronchial hyperresponsiveness and parental ISAAC questionnaire responses

The predictive value of parental questionnaire responses for exercise-induced bronchoconstriction in childhood asthma has not been fully clarified. The aim of this study was to compare exercise-induced bronchial hyperresponsiveness in 7 year old children with parental responses to core questions in the International Study of Asthma and Allergies in Childhood (ISAAC) study. A cross-sectional study was conducted on 191 (91% of eligible) children from seven randomly selected schools in Southern Tasmania. Study measurements included a parental questionnaire and exercise challenge testing, using a recently validated 6 min free-running protocol. The response to exercise was assessed using forced expiratory volume in one second (FEV1) measurement. The median percentage fall in FEV1 was significantly higher in children whose parents responded positively to ISAAC questions on a history of wheeze (p = 0.0031) or asthma (p = 0.0005), recent wheeze (p = 0.0005), sleep disturbance due to wheeze (p = 0.0005), or exercise-induced wheeze (p = 0.0015). Receiver operating characteristic (ROC) curve analysis showed exercise-induced bronchial hyperresponsiveness to be a good indicator of current asthma status. Using a 12% or greater fall in FEV1 postexercise as a positive test response, the exercise challenge had sensitivity and specificity estimates for current asthma and exercise-induced wheeze of (0.58 and 0.77) and (0.60 and 0.77), respectively. In conclusion, the respiratory response to exercise was consistent with parental responses to the ISAAC questionnaire in a population-based sample of 7 year old children. These findings will assist interpretation of large ISAAC studies in terms of asthma prevalence.

A double-blind, placebo controlled study of the effect of the specific histamine H1-receptor antagonist, terfenadine, in chronic severe asthma

1. The characteristic changes seen in asthma are widely regarded as being caused by local mediator release in the airways, with histamine the first putative mediator in asthma to be identified. 2. We performed a double-blind, randomised, placebo-controlled crossover trial of the effect of 4 weeks treatment with terfenadine 120 mg twice daily in chronic severe asthma. 3. Forty-two subjects (20 male and 22 female) completed the 10 week study. 4. Terfenadine had no significant treatment effect on the primary efficacy variables measured. Mean (95% CI) measurements for terfenadine vs placebo treatment periods were 1.5 vs 1.5 (-0.3, 0.3) l for FEV1, 259 vs 260 (-42, 40) l min-1 for morning PEF and 0.8 vs 0.8 (-0.3, 0.3) for global symptom scores. 5. Bronchodilator use and sleep disturbance, the secondary efficacy variables studied, showed an improvement during terfenadine treatment but this only reached statistical significance for the number of times subjects awoke from sleep (P = 0.04). 6. There was a similar frequency of minor adverse effects reported during placebo (13.6%) and terfenadine (16.7%) treatments. 7. Addition of the potent and specific histamine H1-receptor antagonist terfenadine to maintenance asthma treatment had no significant therapeutic benefit in this group of chronic severe asthmatics.

The reproducibility and effect on non-specific airway responsiveness of inhaled prostaglandin D2 and leukotriene D4 in asthmatic subjects

1. Mast cell mediators PGD2 and LTD4 may play important roles in asthma pathogenesis. There is little information on the repeatability of inhalation challenge with these agonists in the laboratory. 2. We assessed the repeatability of inhalation challenges using PGD2 and LTD4 in two groups of 10 asthmatic volunteers. Non-specific bronchial responsiveness was assessed by histamine inhalation challenges. 3. Using the Bland-Altman method, we found the coefficient of repeatability to be 1.2 doubling doses for LTD4 and 2.1 for PGD2 at a 1 week interval. Repeatability for histamine inhalation challenge over the same time period was similar at 1.4 and 2.1 doubling doses respectively. 4. Non-specific bronchial responsiveness following LTD4 challenge decreased significantly, mean PD20FEV1 increasing from 169 nmol on day 1 to 278 nmol on day 3 (P = 0.001), before returning to baseline levels. 5. A progressive decrease in non-specific bronchial responsiveness occurred following PGD2 challenge. Baseline PD20FEV1 was 195 nmol, increasing to 238 nmol by day 3 (NS) and 313 nmol by day 8 (P = 0.016). 6. PGD2 inhalation challenges performed a week apart are less reproducible than LTD4 challenges, possibly as a result of significant changes in histamine bronchial responsiveness. Our findings allow accurate power calculations to be made for studies to assess new pharmacological antagonists to these mediators.

An audit and international comparison of asthma management in the emergency department

AIMS

1. To perform an audit of asthma management in the Christchurch Hospital emergency department during the period March 1987 to August 1988. 2. To compare management of asthma in Christchurch with other centres in New Zealand and the United Kingdom. 3. To compare markers of asthma severity on admission with other centres.

METHODS

Details of all attendances by adults to the Christchurch Hospital emergency department with acute asthma during the above period were recorded on specially designed asthma treatment sheets. This data was compared with similar studies performed in Wellington (NZ) and Southampton and Leicester (UK).

RESULTS

759 cases were analysed. Most subjects were in the 15-25 year age group. 47% were taking inhaled corticosteroids at presentation. History taking was satisfactory according to guidelines operative at that time. Peak flow rate measurement at presentation was performed in 79% of cases, and in 67% of cases following treatment. Nebulised bronchodilators were given in 88% of cases and parenteral steroids given in 22%. 46% of cases were discharged home and of these 28% received a course of oral prednisone. All management decisions, except the decision to give oral steroids on discharge, showed a relationship to objective indices of asthma severity.

CONCLUSION

Comparison with other centres shows that the treatment of acute asthma in Christchurch was of a similar standard. Severity of asthma on presentation, as measured by peak flow and pulse rates showed no difference between Christchurch and Southampton.

Plasma and urinary histamine in allergen-induced early and late phase asthmatic responses

The local release of histamine is considered to be largely responsible for the early asthmatic response to inhaled allergen, although its contribution to the late response is less well-established. To investigate this we have measured the changes in forced expiratory volume in one second (FEV1), plasma histamine and urinary N tau-methylhistamine, in 10 asthmatics following inhaled allergen. To estimate the significance of any changes, we also measured plasma histamine concentrations following inhalation of histamine by nine normal subjects. Following allergen inhalation, the FEV1 fell a mean maximum 38% (SD 13%) from baseline at 15 min, associated with an increase in plasma histamine from a mean (SD) 0.22 (0.08) to 0.64 (0.47) ng.ml-1 at 10 min. During the late asthmatic response, plasma histamine concentrations did not depart significantly from baseline concentrations. There were no significant changes in urinary N tau-methylhistamine excretion. Inhalation of histamine by normal subjects at concentrations up to 4 mg.ml-1 showed no significant change in plasma concentrations, but at 16 mg.ml-1 there was an increase from a mean (SD) baseline 0.25 (0.10) ng.ml-1 to a mean maximum 0.83 (0.53) ng.ml-1 at 1 min. The early asthmatic response to inhaled allergen in asthmatics is accompanied by a significant increase in plasma histamine, approximately equivalent to an inhaled concentration of 16 mg.ml-1, whereas no significant changes in histamine were found during the late asthmatic response.

The comparative actions and adverse effect profile of single doses of H1-receptor antihistamines in the airways and skin of subjects with asthma

BACKGROUND

The development of potent H1-receptor antagonists that are free of adverse effects has renewed interest in their use in the treatment of asthma.

METHODS

We performed a study of the action of chlorpheniramine, terfenadine, brompheniramine, cetirizine, cyproheptadine, clemastine, and astemizole compared with placebo on histamine-induced skin wheals and bronchoconstriction in a single group of patients with asthma. Another group underwent methacholine bronchoprovocation.

RESULTS

Antihistamine pretreatment increased mean baseline measurements of forced expiratory volume in 1 second (FEV1) between 2.58% and 9.28% compared with placebo, which was significant for all drugs except brompheniramine and clemastine. Compared with placebo, all antihistamines provided significant protection against histamine-induced bronchoconstriction when measured as the provocation concentration required to cause a 20% fall in FEV1; terfenadine and cetirizine provided significantly greater protection than other antihistamines. Protection against histamine-induced skin wheals, measured as the slope of the log concentration-response curve, was only significant for the new drugs, terfenadine and cetirizine. There was a good correlation between the protective effect of the drugs in the skin and airways (r = 0.85; p < 0.01). No significant difference in methacholine provocation concentration required to cause a 20% fall in FEV1 values between treatments was found.

CONCLUSIONS

The new H1-receptor antagonists terfenadine and cetirizine provided significantly better protection than the older antihistamines against the action of histamine in the skin and airways. None of the antihistamines showed evidence of anticholinergic activity in the asthmatic airways at the doses studied.

The time course of action of three differing doses of noberastine, a novel H1-receptor antagonist, on histamine-induced skin wheals and the relationship to plasma drug concentrations in normal human volunteers

1. The time course and magnitude of effect of the novel H1-receptor antagonist noberastine, structurally modified from astemizole to achieve a more rapid onset while retaining a good duration of action, has been investigated using histamine-induced skin wheals in healthy volunteers. 2. The pharmacokinetics and pharmacodynamics of three doses (10, 20 and 30 mg) have been studied in a double-blind, placebo controlled, randomised cross-over trial involving 12 healthy male volunteers. 3. All doses of noberastine caused inhibition of histamine-induced skin wheals, which were significantly different from placebo (P < 0.0001) when assessed as the area under the percent inhibition of the response vs time curves. 4. Following single dose administration of 10, 20 and 30 mg noberastine significant inhibition of histamine-induced skin wheals occurred and this effect persisted beyond 24 h. 5. At the higher (20 and 30 mg) doses studied significant inhibition of the histamine-induced skin wheal occurred by 1 h of dosing, whereas this did not occur until 2 h following the 10 mg dose. 6. An increase in plasma concentrations of noberastine was seen after administration of all doses, with mean (s.d.) concentrations of 4.14 (3.70), 8.38 (7.81) and 12.66 (11.82) ng ml-1 1 h following administration of 10, 20, and 30 mg respectively. 7. Visual analogue scale measurements of drowsiness identified no sedative effects above those of placebo at any of the dose levels. 8. We conclude that noberastine is an effective H1-receptor antagonist in the human as assessed by its effect on histamine-induced skin wheals.

Role of leukotrienes in exercise-induced asthma. Inhibitory effect of ICI 204219, a potent leukotriene D4 receptor antagonist

The sulfidopeptide leukotrienes C4, D4, and E4 are released from mast cells in response to allergen challenge and may be involved in the bronchoconstrictor response to inhaled allergen in asthma. Since mast cell activation may also be implicated in exercise-induced bronchoconstriction, we assessed the inhibitory effects of a potent orally active leukotriene D4 receptor antagonist, ICI 204219 (20 mg), on the bronchoconstrictor response to exercise in eight male asthmatic patients in a placebo-controlled, randomized crossover study. Exercise challenge respiring dry air was performed on a treadmill at constant speed and gradient 2 h after drug administration, and bronchoconstriction was assessed as change in FEV1 over 30 min postexercise. No significant effect on airway caliber, measured as FEV1, was noted 2 h after ICI 204219. The mean maximum percentage fall in FEV1 following exercise was 36.0% following placebo, and reduced to 21.6% after ICI 204219 (p less than 0.01). Analysis of the time course of bronchoconstriction showed that inhibition was most marked over the latter part of the period assessed. These data indicate that the release of sulfidopeptide leukotrienes makes a major contribution to exercise-induced bronchoconstriction.

Reassessment of asthma management in an accident and emergency department

To determine if shortcomings in asthma management in the Accident and Emergency (A & E) department identified in a previous (1983) study (Reed et al. Thorax 1985; 40: 897-902) had been corrected, we retrospectively reviewed the case records of patients attending with asthma between December 1987 and November 1988. There was an increase in the number of patients attending with asthma; 0.73 per 1000 in 1988 versus 0.57 per 1000 in 1983. Sixty-seven percent of patients were self-referred and 80% presented between 1600 h and 0800 h. There was inadequate recording of the asthma history and examination findings. Peak expiratory flow (PEF) was recorded in 86% before treatment (compared to 11% in 1983) and 70% after treatment. In addition, a prospective study of 40 patients responding to a questionnaire 2 weeks after discharge, revealed persistent symptoms of unstable asthma in 50%. Although there has been a marked improvement in the use of PEF measurements since the 1983 study, the standards of management of asthma patients may still be inadequate as evidence by the presence of unstable asthma symptoms in many of those discharged. A standardized management protocol which provides guidelines for treatment based on PEF has been introduced to the A & E department.

Dose-response relationship of the H1-histamine antagonist, ebastine, against histamine and methacholine-induced bronchoconstriction in patients with asthma

In a double blind, randomised, placebo controlled trial in a group of extrinsic asthmatics, we have evaluated the potency and selectivity of ebastine, a new piperidine-type H1-receptor antagonist, against histamine and methacholine-induced bronchoconstriction. The median histamine PC20FEV1 value following placebo was 3.15 mg/ml (0.24-58.84). When compared with placebo, ebastine produced significant protection at 10 mg (median PC20 = 31.36 mg/ml, p = 0.008) and 30 mg (median PC20 = 42.14 mg/ml, p = 0.001) but there appeared to be no significant dose effect. Ebastine also produced a small shift in the methacholine concentration-response curves to the right. We conclude that ebastine is an effective antagonist of histamine-induced bronchoconstriction in the asthmatic airway with evidence of minor blockade of methacholine-induced bronchoconstriction.