Effect of therapy on bronchial hyperresponsiveness in the long-term management of asthma

The use of a direct bronchial challenge test in primary care to diagnose asthma

Many asthmatics in primary care have mild symptoms and lack airflow obstruction. If variable expiratory airflow limitation cannot be determined by spirometry or peak expiratory flow, despite a history of respiratory symptoms, a positive bronchial challenge test (BCT) can confirm the diagnosis of asthma. However, BCT is traditionally performed in secondary care. In this observational real-life study, we retrospectively analyze 5-year data of a primary care diagnostic center carrying out BCT by histamine provocation. In total, 998 primary care patients aged ≥16 years underwent BCT, without any adverse events reported. To explore diagnostic accuracy, we examine 584 patients with a high pretest probability of asthma. Fifty-seven percent of these patients have a positive BCT result and can be accurately diagnosed with asthma. Our real-life data show BCT is safe and feasible in a suitably equipped primary care diagnostic center. Furthermore, it could potentially reduce diagnostic referrals to secondary care.

Long-term intense exposure to grass pollen can mask positive effects of allergenic immunotherapy on non-specific bronchial hyperresponsiveness

INTRODUCTION

There are many potential factors that can modulate bronchial reactivity, including exposure to allergens, viral infections, and medications. The aim of this study was to analyze the effect of grass pollination intensity on the bronchial reactivity in seasonal allergic rhinitis (SAR) patients subjected to subcutaneous allergenic immunotherapy (SCIT).

MATERIAL AND METHODS

This study, performed between 2005 and 2008, included 41 patients with confirmed sensitivity to grass pollens and predominating symptoms of SAR, randomly assigned to desensitization by pre-seasonal or maintenance SCIT. Bronchial provocation challenge with histamine was performed before the onset of immunotherapy, and repeated three times after each pollen season covered by this study. Bronchial reactivity was analyzed with regard to grass pollination intensity in 2005-2008 (air concentration of grass pollen grains, seasonal number of days when air concentration of grass pollen reached at least 20 or 50 grains per 1 m(3)).

RESULTS

After 3 years of SCIT, a significant decrease in bronchial responsiveness was observed in the analyzed group as confirmed by an increase in PC20 FEV1 histamine values (p = 0.001). An inverse tendency was observed after 2 years of SCIT, however. This second year of SCIT corresponded to the 2007 season, when a significantly higher number of days with at least 50 grains of pollen per 1 m(3) of air was recorded.

CONCLUSIONS

FLUCTUATIONS IN POLLINATION INTENSITY OBSERVED DURING CONSECUTIVE YEARS OF IMMUNOTHERAPY CAN INFLUENCE BRONCHIAL REACTIVITY IN PATIENTS SUBJECTED TO SCIT (ISRCTN REGISTER: ISRCTN 86562422).

Airway smooth muscle as a target in asthma and the beneficial effects of bronchial thermoplasty

Airflow within the airways is determined directly by the lumenal area of that airway. In this paper, we consider several factors which can reduce airway lumenal area, including thickening and/or active constriction of the airway smooth muscle (ASM). The latter cell type can also contribute in part to inflammation, another feature of asthma, through its ability to take on a synthetic/secretory phenotype. The ASM therefore becomes a strategically important target in the treatment of asthma, given these key contributions to the pathophysiology of that disease. Pharmacological approaches have been developed to elicit relaxation of the ASM, but these are not always effective in all patients, nor do they address the long-term structural changes which impinge on the airway lumen. The recent discovery that thermal energy can be used to ablate smooth muscle has led to the development of a novel physical intervention—bronchial thermoplasty—in the treatment of asthma. Here, we review the evolution of this novel approach, consider some of the possible mechanisms that account for its salutary effects, and pose new questions which may lead to even better therapies for asthma.

Prognosis of adult asthma after normalization of bronchial hyperresponsiveness by inhaled corticosteroid therapy

BACKGROUND

Inhaled corticosteroids (ICSs) are the most effective anti-inflammatory drugs for adult asthma and can improve not only clinical symptoms but also bronchial hyperresponsiveness (BHR). However, the prognosis of adult asthma has not been well studied, and it remains to be elucidated precisely how long treatment with ICSs should be continued once clinical remission is achieved.

OBJECTIVES

We examined whether ICS use could be withdrawn or reduced without exacerbation of disease.

METHODS

We retrospectively studied 374 adult patients with asthma to determine which factors predicted the elimination or reduction of ICS treatment without exacerbations of disease after the achievement of normalized BHR to acetylcholine. The patients were classified into three groups: Group 1 had symptoms within 6 months of normalization and needed to continue therapy; group 2 received the equivalent of >or= 400 microg fluticasone propionate until BHR normalization, did not have symptoms in the 6 months after normalization, and then had their doses of ICSs halved; and group 3 received the equivalent of <or= 200 microg fluticasone propionate at an enrollment, did not have symptoms in the 6 months after normalization, and then had all ICSs withdrawn. The primary outcome measure was the presence of clinical symptoms. We used multiple logistic regression and a Kaplan-Meier analysis to analyze the factors predicting remission.

RESULTS

Twenty-nine patients in group 3 remained asymptomatic for more than 30 months (mean 47.1 +/- 12.4 months) after discontinuing ICS therapy. The predictive markers of remission were low levels of eosinophils in the sputum, high %V(50) at the first hospital visit, and the need for only a low daily dose of ICS to induce normalized BHR. Conversely, patients with severe BHR at the first hospital visit, low %FEV(1) at normalized BHR, and a need for high-dose ICSs to reach normalized BHR could not reduce or discontinue treatments.

CONCLUSION

Some adult patients with asthma whose BHR is normalized by ICS therapy can achieve remission from disease exacerbation after discontinuation of ICSs. However, patients with severe asthma or asthma of long duration may not achieve remission even if their BHR is normalized.

Home monitoring in asthma self-management

Peak flow monitoring of asthma came into vogue with the advent of asthma self-management programs. Because it offered an objective way to gauge asthma severity, it promised improvement in the accuracy of asthma monitoring over that attainable by symptom monitoring. This promise has not been fulfilled. The ensuing years have witnessed a debate concerning the relative merits of symptom and peak flow monitoring. The debate has focused both on the degree to which peak flow and symptom scores are related to one another and on the relative effectiveness of symptom and peak flow monitoring for asthma control. We review research relating to these topics. The work shows that the strength of the relationship between peak flow and symptoms is low to moderate and varies between individuals and that benefits of peak flow monitoring in asthma self-management provide, at best, no more than a small increment in effectiveness beyond that afforded by symptom monitoring.

Adequacy of outpatient management of asthma patients admitted to a state hospital in Argentina

OBJECTIVE

The aim of this study was to assess chronic outpatient management of adult patients admitted with asthma.

METHODOLOGY

A cross-sectional survey was conducted of 98 consecutive asthma admissions to a specialized pulmonary State Hospital in Buenos Aires, Argentina, over a 12-month period. Patients were surveyed, within 48 h of admission, with a previously validated questionnaire which deals with chronic outpatient management and measures taken by patients or physicians to treat symptoms during asthma exacerbations.

RESULTS

FEV1% predicted was 30.2 +/- 10.7. Mean admission rate and emergency department (ED) visits in the previous year were 0.7 +/- 1.2 and 4.6 +/- 5.1, respectively. A total of 96, 65 and 9% of the patients had been treated previously in the ED, admitted to hospital or mechanically ventilated, respectively. Only 62% had been prescribed inhaled corticosteroids (IC) by their physician; 38% had been prescribed nebulized beta agonists (Nbeta2) and 68% a metered dose inhaler (MDIbeta2). Inhaled beta2-agonist usage during acute exacerbations over the 24 h prior to admission was 14.4 +/- 7.4 puffs for MDIbeta2 and 8.6 +/- 5.4 occasions for Nbeta2. Only 11% of the patients were able to perform all the steps of the MDI inhalation technique correctly. An action plan had been provided by their physicians to 43% of patients, while 58% changed their medication on their own. Only three patients had a peak flow meter (PFM) prescribed. ED was used by 26% for their routine care. No health insurance coverage was available to 75.5% of the patients.

CONCLUSIONS

Underuse of IC, poor MDI inhalation technique, and low prescription of an action plan was common and a PFM was seldom prescribed. During exacerbations, many patients changed their medication spontaneously and MDIbeta2 underuse was observed.

Effects of allergen inhalation and oral glucocorticoid on concentrations of serum-soluble CD86 in allergic asthmatics

The aim of the present study was to investigate effects of allergen inhalation and oral glucocorticoid on concentration of serum soluble CD86 in patients with allergic asthma. Our results showed that the serum soluble CD86 concentrations in the dual responder group increased from 491.8 +/- 15.4 IU/ml before allergen inhalation to 603.8 +/- 19.3 IU/ml 24 h after allergen inhalation. In the isolated early responders, there was no significant increase in serum soluble CD86 concentrations after allergen inhalation compared with baseline levels. There was a significant decrease in serum soluble CD86 concentrations after 2 weeks of glucocorticoid therapy (448.3 +/- 15.1 IU/ml) compared with baseline values (532.7 +/- 12.3 IU/ml), whereas there was no significant difference in the placebo group. This study has demonstrated that serum soluble CD86 concentrations increased after allergen inhalation in sensitized asthmatic subjects, and that serum sCD86 concentrations were downregulated by prednisolone therapy.

[The therapeutic index in asthma: how should it be defined?]

INTRODUCTION

The therapeutic index (efficacy/tolerance or benefit/risk ratio) is a major determinant of treatment decisions in asthma.

METHODS

For the numerator, the therapeutic index depends on efficacy (maximal effect) and not potency (dose-response relationship). With regard to the denominator, several pharmacological factors influence the occurrence of side-effects, the acceptability of which also has to be considered.

RESULTS

In asthma, some strategies have a more favourable therapeutic index than others;e.g additional treatment (long acting beta2 agonists, leukotriene receptor antagonists, theophylline) to inhaled corticosteroids instead of doubling the dose of the latter. Conversely, it is extremely difficult to compare the therapeutic indices of different molecules of inhaled corticosteroids.

CONCLUSIONS

The potential risk of systemic side effects with long-term administration of high doses of inhaled corticosteroids suggests the need to seek the minimal effective dose.

Monitoring response to treatment in asthma management: food for thought

Asthma is a chronic inflammatory disorder of the airways that is characterized by episodic symptoms. In this regard, asthma management has classically involved periodic re-assessment by the health-care provider, during which therapy is altered mainly based on clinical and physiological parameters, such as assessment of symptoms, spirometry and peak expiratory flow monitoring. In this context, various markers of airway inflammation (e.g. eosinophils in the induced sputum, nitric oxide in the exhaled air) have been proposed to assess the severity of asthma and to adjust the therapy accordingly. The evaluation of airway hyper-responsiveness with different stimuli has also been suggested as a new tool to monitor asthma. However, the lack of definite relationships between airway inflammation and asthmatic symptoms strongly limit the use of markers of asthma severity in the clinical setting. Therefore, the need of new tools to assess the severity of asthma is raised. The ideal measurement employed to establish the proper asthmatic therapy should be safe, non-invasive, easy to perform, reproducible and accurate, and have the capability to monitor the changes induced by the therapeutic interventions. A careful review of the available techniques, and the evaluation of their sensitivity and specificity in the clinical setting is warranted.

Pharmacotherapy and airway remodelling in asthma?

Over the last few decades attention has largely focused on airway inflammation in asthma, but more recently it has been appreciated that there are important structural airway changes which have been grouped together under the term "airway remodelling". It is only now that questions have been asked about the impact of treatment on these structural changes. This review examines the nature of these structural airway changes, the mechanisms of their generation, their potential consequences, and what is known about the ability of anti-asthma treatments to modulate these changes.

Obesity is a risk for asthma and wheeze but not airway hyperresponsiveness

BACKGROUND

A study was undertaken to assess whether the recent increases in prevalence of both asthma and obesity are linked and to determine if obesity is a risk factor for diagnosed asthma, symptoms, use of asthma medication, or airway hyperresponsiveness.

METHODS

Data from 1971 white adults aged 17-73 years from three large epidemiological studies performed in NSW were pooled. Doctor diagnosis of asthma ever, history of wheeze, and medication use in the previous 12 months were obtained by questionnaire. Body mass index (BMI) in kg/m(2) was used as a measure of obesity. Airway hyperresponsiveness (AHR) was defined as dose of <3.9 micromol histamine required to provoke a fall in forced expiratory volume in one second (FEV(1)) of 20% or more (PD(20)FEV(1)). Adjusted odds ratios (OR) were obtained by logistic regression.

RESULTS

After adjusting for atopy, age, sex, smoking history, and family history, severe obesity was a significant risk factor for recent asthma (OR 2. 04, p=0.048), wheeze in the previous 12 months (OR 2.6, p=0.001), and medication use in the previous 12 months (OR 2.83, p=0.005), but not for AHR (OR 0.87, p=0.78). FEV(1) and forced vital capacity (FVC) were significantly reduced in the group with severe obesity, but FEV(1)/FVC ratio, peak expiratory flow (PEF), and mid forced expiratory flow (FEF(25-75)) were not different from the group with normal BMI. The underweight group (BMI <18.5 kg/m(2)) had increased symptoms of shortness of breath, increased airway responsiveness, and reduced FEV(1), FVC, PEF, and FEF(25-75) with similar use of asthma medication as subjects in the normal weight range.

CONCLUSIONS

Although subjects with severe obesity reported more wheeze and shortness of breath which may suggest a diagnosis of asthma, their levels of atopy, airway hyperresponsiveness, and airway obstruction did not support the suggestion of a higher prevalence of asthma in this group. The underweight group appears to have more significant respiratory problems with a higher prevalence of symptoms, reduced lung function, and increased airway responsiveness without an increase in medication usage. This group needs further investigation.

Case-control study of severe life threatening asthma (SLTA) in adults: demographics, health care, and management of the acute attack

BACKGROUND

Severe life threatening asthma (SLTA) is important in its own right and as a proxy for asthma death. In order to target hospital based intervention strategies to those most likely to benefit, risk factors for SLTA among those admitted to hospital need to be identified. A case-control study was undertaken to determine whether, in comparison with patients admitted to hospital with acute asthma, those with SLTA have different sociodemographic and clinical characteristics, evidence of inadequate ongoing medical care, barriers to health care, or deficiencies in management of the acute attack.

METHODS

Seventy seven patients with SLTA were admitted to an intensive care unit (pH 7.17 (0.15), PaCO(2) 10.7 (5.0) kPa) and 239 matched controls (by date of index attack) with acute asthma were admitted to general medical wards. A questionnaire was administered 24-48 hours after admission.

RESULTS

The risk of SLTA in comparison with other patients admitted with acute asthma increased with age (odds ratio (OR) 1.04/year, 95% CI 1.01 to 1.07) and was less for women (OR 0.36, 95% CI 0.20 to 0.68). These variables were controlled for in all subsequent analyses. There were no differences in other sociodemographic features. Cases were more likely to have experienced a previous SLTA (OR 2.04, 95% CI 1.20 to 3.45) and to have had a hospital admission in the last year (OR 1.86, 95% CI 1.09 to 3.18). There were no differences between cases and controls in terms of indicators of quality of ongoing asthma specific medical care, nor was there evidence of disproportionate barriers to health care. During the index attack cases had more severe asthma at the time of presentation, were less likely to have presented to general practitioners, and were more likely to have called an ambulance or presented to an emergency department. In terms of pharmacological management, those with SLTA were more likely to have been using oral theophylline (OR 2.14, 95% CI 1.35 to 3.68) and less likely to have been using inhaled corticosteroids in the two weeks before the index attack (OR 0.69, 95% CI 0.47 to 0.99). While there was no difference in self-management knowledge or behaviour scores, those with SLTA were more likely to have inappropriately used oral corticosteroids during the acute attack (OR 2.09, 95% CI 1.02 to 4.47).

CONCLUSIONS

In comparison with those admitted to hospital with acute severe asthma, patients with SLTA were indistinguishable on sociodemographic criteria (apart from male predominance), were more likely to have had a previous SLTA or hospital admission in the previous year, had similar quality ongoing asthma care, had no evidence of increased physical, economic or other barriers to health care, but had demonstrable deficiencies in the management of the acute index attack. Educational interventions, while not losing sight of the need for good quality ongoing care, should focus on providing individual patients with better advice on self-management of acute exacerbations.

Effects of several glucocorticosteroids and PDE4 inhibitors on increases in total lung eosinophil peroxidase (EPO) levels following either systemic or intratracheal administration in sephadex- or ovalbumin-induced inflammatory models

Representative glucocorticosteroids (GCS) and phosphodiesterase IV (PDE4) inhibitors were compared in several models of pulmonary inflammation ranging in severity. Lung tissue eosinophil peroxidase (EPO) levels rather than bronchoalveolar lavage fluid (BALF) EPO or eosinophil percentages were used to indicate eosinophil recruitment after intratracheal instillation of sephadex beads in rats or nebulized ovalbumin in sensitized guinea pigs. A single oral or intratracheal administration of a GCS was effective against mild and robust sephadex-induced eosinophilia whereas the PDE4 inhibitors evaluated appeared more effective in the milder sephadex models. The GCS were also more effective against sephadex-induced than ovalbumin-induced eosinophilia. The effectiveness of the GCS and PDE4 inhibitors improved when the severity of the ovalbumin-induced eosinophilia was decreased. Multiple day dosing also improved activity. These studies indicated that activity was influenced greatly by administration protocols, the severity of the inflammatory response and possibly the method used for estimating eosinophil recruitment.

Influence of peak expiratory flow monitoring on an asthma self-management education programme

We assessed whether peak expiratory flow monitoring added to a self-management education programme reduced morbidity and improved pulmonary function and adherence to treatment in 100 asthma patients (aged 17-65 years) with adequate treatment and regular 1-year follow-up. Patients randomized to the experimental group used peak expiratory flow readings as the basis for their therapeutic plan coupled with educational intervention, whereas patients in the control group received the same educational intervention and used symptoms only to guide self-management. Morbidity parameters, functional status and adherence to medical regimens improved in both groups, although the percentage of patients with satisfactory adherence was significantly better in the group with peak expiratory flow monitoring (83%) than in controls (52%) (P = 0.05). The multivariate analysis showed that severity of asthma (odds ratio 9.28, 95% confidence interval 1.87-45.96, P = 0.006 for moderate asthma) and type of self-management education programme (odds ratio: 6.19; 95% confidence interval: 2.04-18.81; P = 0.001 for the use of peak expiratory flow readings) were the only independent predictors of adherence to treatment. However, a statistically significant association between adherence and use of peak expiratory flow monitoring was only found in patients with moderate asthma (P = 0.0009). We conclude that peak expiratory flow monitorization in optimal conditions (adequate medical regimen, individualized self-management education and regular follow-up) showed a beneficial effect on adherence to prescribed regimens only in patients with moderate asthma.

Demographic characteristics of patients experiencing near-fatal and fatal asthma: results of a regional survey of 400 asthma specialists [see comment]

BACKGROUND

Case-control studies now describe a growing number of younger patients with varying levels of asthma severity who experience near-fatal or fatal asthma unexpectedly at home, en route to the hospital, or in public places.

OBJECTIVE

To collect case reports and analyze the demographic characteristics and patient profiles that may help identify predisposing factors which trigger near-fatal and fatal asthma episodes.

METHODS

In order to gather case reports and analyze the demographics and clinical characteristics of patients experiencing near-fatal and fatal asthma, a questionnaire on near-fatal and fatal asthma was distributed to 400 regional asthma specialists.

RESULTS

Forty physicians reported 25 cases of near-fatal asthma and 20 cases of fatal asthma. Twenty-five patients (13 males and 12 females) with a mean age of 29.4 years experienced near-fatal asthma. The time of onset of the near-fatal event was sudden (less than 3 hours) in 60% of cases and 76% of the episodes occurred at home or en route to the hospital. All 25 patients were using short acting inhaled beta agonists and 88% were reportedly using inhaled corticosteroids on a daily basis. Good to excellent compliance was noted in 60% of patients. Six patients were using a peak flow meter prior to their near-fatal attack. Predisposing psychosocial factors for life threatening asthma were noted in 44% of patients. Twenty patients, (4 males and 16 females) with a mean age of 21.7 years experienced fatal asthma. The time of onset of the fatal event was sudden (less than 3 hours) in 80% of cases and all but one patient died at home, en route to the hospital, or in a public place. All 20 patients were using short acting inhaled beta agonists, 80% were reportedly on daily inhaled corticosteroids and six patients were on oral corticosteroids. Good to excellent compliance was noted in 60% of patients. Only two patients were using a peak flow meter immediately prior to their fatal attack. Predisposing psychosocial factors for life threatening asthma were noted in 45% of decedent patients. Risk factors for fatal asthma included running in cold weather, over relying on home nebulizers, and a delay in seeking care on long holiday weekends.

CONCLUSIONS

While approximately 50% of the patients in this survey had moderate to severe asthma tainted by adverse psychosocial factors, nearly half of near-fatal and fatal attacks occurred suddenly and unexpectedly, outside the hospital in stable, younger, atopic, reportedly compliant patients utilizing inhaled corticosteroids on a daily basis. This regional survey supports the need for additional studies and the establishment of a national case registry to collect case reports and analyze the demographics and clinical characteristics of patients experiencing near-fatal and fatal asthma in order to further define the risk factors and develop preventative protocols for patients at risk for near-fatal or fatal asthma.

New considerations about measuring airway hyperresponsiveness

Measuring airway responsiveness to inhaled bronchoconstrictor stimuli, such as methacholine or histamine, has become an important tool in the diagnosis of asthma. This is measured by patients inhaling increasing doses or concentrations of the bronchoconstrictor stimulus until a given level of bronchoconstriction is achieved. Inhaled allergens initiate processes that increase airway inflammation and enhance airway hyperresponsiveness in asthmatic subjects. Studies using inhaled allergen challenges have provided insight into how changes in airway hyperresponsiveness are regulated by induced inflammatory processes. These changes in airway hyperresponsiveness (1-2 doubling doses) have been shown to be of much smaller magnitude than those demonstrated when asthmatics with stable airway hyperresponsiveness are compared to normals (4-8 doubling doses). These allergen-induced changes would be of little relevance in subjects with normal airway responsiveness, because they would not increase the degree of airway responsiveness into the asthmatic range. They are, however, important in asthmatics who already have airway hyperresponsiveness because they are similar to changes associated with worsening asthma control. It is likely that the mechanisms responsible for the changes in airway hyperresponsiveness following experimental allergen exposure are similar to those producing transient worsening of control in asthmatics. Nevertheless, it is unlikely that the mechanisms of the transient allergen-induced airway hyperresponsiveness will explain the underlying mechanisms of the persistent airway hyperresponsiveness in asthmatic patients when compared with normal individuals.

Can peak expiratory flow predict airflow obstruction in children with asthma?

STUDY OBJECTIVES

A recent trend in the treatment of asthma has been the widespread, independent use of peak expiratory flow (PEF). We examined whether PEF monitoring creates inaccuracies in assessment of children with moderate to severe asthma.

METHODS

We compared the negative predictive value of PEF in relation to the forced expiratory volume in 1 second (FEV(1)), and to the forced expiratory flow between 25% and 75% of the vital capacity (FEF(25-75%)) at different levels of air trapping as determined by the residual volume over total lung capacity ratio (RV/TLC).

RESULTS

The study included 244 patients, ages 4 to 18 years with all classes of asthma severity, with FEV(1) ranging from 28% to 134% of predicted value. We analyzed 367 sets of pulmonary function tests performed throughout a 3-year period. Thirty percent of patients with a normal PEF value had an abnormal FEV(1) or FEF(25-75%). As air trapping increased, the ability of a normal PEF to predict normal FEV(1) and FEF(25-75%) readings fell from 83% to 53%. The negative predictive value was significantly lower for patients with RV/TLC ratio >30 compared with patients with RV/TLC <30.

CONCLUSIONS

The results of this study suggest that it might be possible to identify children for whom the PEF is likely to give false-negative results. As air trapping increases, it causes the PEF to give misleading reassurance of normal pulmonary function. Furthermore, poor predictiveness of PEF is obtained when values 80% of predicted for age are considered normal.

Long-term effects of specific immunotherapy, administered during childhood, in asthmatic patients allergic to either house-dust mite or to both house-dust mite and grass pollen

In a retrospective study, asthmatic patients allergic to either house-dust mite (HDM) (Dermatophagoides pteronyssinus) (n = 34) or to both HDM and grass pollen (GP) (n = 14), and who were treated with specific immunotherapy (SIT) during childhood (mean duration of SIT: 61 +/- 9.70 months), were re-evaluated in early adulthood after mean cessation of SIT for 9.3 +/- 2.76 years. The results were compared to those of a control group of asthmatic patients (n = 42) with comparable asthma features, who were treated with appropriate antiasthmatic drugs during childhood, but who never received SIT. Re-evaluation was carried out with a standardized questionnaire, skin prick tests (SPT), and lung-function assessments. At the time of re-evaluation, the mean age in the SIT-treated group was 23.1 +/- 3.50 years; in the control group, it was 22.7 +/- 3.40 years. At re-evaluation, the risk of frequent asthmatic symptoms was three times higher in the control group than in the SIT-treated group (prevalence ratio: 3.43; P = 0.0006). The frequent use of antiasthmatic medication was also more pronounced in the control group, although the difference was not statistically significant (P=0.38). Lung-function parameters and results of SPT with HDM were comparable in both groups. It is concluded that SIT has long-term effects on asthmatic symptoms in young adults.

How do we monitor asthma control?

The present consensus on asthma management includes avoidance of triggers, education, regular follow-up, and an action plan that relies on symptoms and lung function measurements for the monitoring of disease severity. Inclusion of objective measurements for monitoring seems to be important because patients and physicians may not always recognize asthma symptoms or their severity. However, the additional value of monitoring peak flow and symptoms in guiding asthma therapy has not been well established. Furthermore, it can be questioned whether a treatment strategy which is solely based on optimizing symptoms and lung function leads to optimal control of asthma in each individual patient, since airway hyperresponsiveness (AHR) and airways inflammation may persist. The chronicity of such abnormalities may lead to airways remodelling, thereby worsening the long-term outcome of asthma. It has been shown that AHR provides prognostic information on asthma control, because it can serve as a valuable noninvasive surrogate marker of airways inflammation when added to the guides of asthma therapy. A limited increase in dose of inhaled steroids, instead of applying an increased dose indiscriminately, can be successfully tailored to the needs of the individual patient based on the degree of AHR. Such a strategy leads to both a better clinical outcome and a better histologic outcome. The present worldwide effort is to find alternative markers of airways inflammation in asthma that can be easily implemented in routine practice. In the near future, longitudinal studies will determine which parameter is potentially most useful in guiding asthma management.

How does home management of asthma exacerbations by parents of inner-city children differ from NHLBI guideline recommendations? National Heart, Lung, and Blood Institute

OBJECTIVES

1) To describe the asthma morbidity, primary care practices, and asthma home management of inner-city children with asthma; 2) to determine the responses of parental caretakers to asthma exacerbations in their child; and 3) to compare these responses to the recommendations of the National Heart, Lung, and Blood Institute (NHLBI) asthma guidelines for home management of acute exacerbations of asthma.

DESIGN AND METHODS

A 64-item telephone survey was administered between July 1996 and June 1997 to 220 parental caretakers of 2- to 12-year-old children who had been hospitalized with asthma at an inner-city medical center from January, 1995 to February, 1996. Sociodemographics, primary care practices, asthma morbidity, and asthma home management were assessed. Parents were asked what they would do if their child "began wheezing and breathing faster than usual."

RESULTS

Morbidity measures indicated that there were an average of 2.5 +/- 4.5 emergency department visits for asthma in the last 6 months, 1.6 +/- 2.2 hospitalizations for asthma in the last 12 months, and 18.1 +/- 17.9 asthma-related school absences in the previous school year. Most, but not all, of the families had primary care providers and most had phone access to them. Half of the families (51%) reported having been given a written asthma action plan. Only 30% of families with children age 5 years and older had peak flow meters. In contrast, almost all families (97%) had equipment for inhalation of beta-agonists. Only 39% of the 181 children with persistent symptoms were receiving daily antiinflammatory agents as recommended in the guidelines of the NHLBI. In response to the scenario of an acute exacerbation of asthma, no one mentioned that they would refer to a written plan, only 1 caretaker would measure peak flow and 36% would give beta-agonists. Two percent would give oral steroids initially, and 1 additional person would do so if wheezing continued 40 minutes later. Only 4% responded that they would contact their clinician. Reports of actual practice differed from the scenario responses in that more people began beta-agonists and oral steroids in response to an exacerbation in the past 6 months than said they would in response to the scenario.

CONCLUSION

In this population of previously hospitalized inner-city children with asthma, the NHLBI guidelines for the home management of asthma exacerbations are not being followed. Interventions are needed to affect both clinician and caretaker practices.

Mild experimental exacerbation of asthma induced by individualised low-dose repeated allergen exposure. A double-blind evaluation

Low doses of environmental allergens have been proposed to increase bronchial hyperreactivity in sensitised individuals, without causing immediate asthmatic reactions. The primary aim of the present study was to evaluate whether repeated low doses of allergen, that do not cause overt bronchoconstriction, cause augmented non-specific bronchial reactivity. A secondary aim was to evaluate whether any changes in reactivity are associated with increased variability of lung function, and whether signs of inflammatory activity could be found. To do this, mild asthmatic patients without regular symptoms, but with both immediate and late reactions in response to a high dose of inhaled cat allergen extract, were included in a double blind, placebo controlled, cross-over study in which a low dose of allergen was administered on four consecutive days (Monday to Thursday). The dose of allergen was individualised for each patient, and was calculated to be 25% of the total dose given to produce an immediate and late response at screening. Repeated low dose allergen exposure produced a significant increase in methacholine reactivity compared to placebo, whereas FEV1 in the morning did not significantly change during the allergen week. Each low dose allergen exposure caused small changes in FEV1 (approximately 7% drop), which was significant vs. placebo only on day 2 (Tuesday). During the allergen week, six of eight patients reported asthma symptoms on at least one occasion, and variability in lung function, measured with a portable spirometer, was increased. Repeated low doses of allergen also produced a significant increase of P-ECP vs. placebo, without a significant rise in circulating eosinophils. However, no significant changes in circulating CD3, CD4, CD8, CD19, or CD25 cells were found, evaluated by FACS analysis. We conclude that low doses of allergen produce signs of a mild exacerbation of asthma, including increased bronchial reactivity to methacholine. This clinical model may be useful to evaluate both the pathophysiological mechanisms of asthma, and the effects of novel anti-asthma drugs.

Comparison of 3 different doses of budesonide and placebo on the early asthmatic response to inhaled allergen

BACKGROUND

A simple laboratory method to evaluate relative potency of inhaled corticosteroids in asthma would be valuable. Single-dose studies with the allergen-induced late asthmatic response have failed to show a useful dose-response relationship. Treatment for several days with inhaled corticosteroids will also inhibit the allergen-induced early asthmatic response.

METHODS

Twelve atopic asthmatic subjects were studied during a season when no medications were required except ipratropium bromide as needed. These subjects had positive allergen and methacholine inhalation tests and FEV1 greater than 70% of predicted value. A double-blind, randomized, cross-over study compared placebo and budesonide 100, 200, and 400 microg administered by means of Turbuhaler twice daily for 7 days with 6-day washout periods. Methacholine PC20 was measured before and after 6 days of treatment, and allergen PC15 was measured after 7 days of treatment.

RESULTS

The allergen PC15 (n = 11) was significantly larger (P = .0001) for all doses of budesonide compared with placebo, but there was no significant difference between the 3 doses of budesonide, and no dose response was demonstrated. The methacholine PC20 was significantly larger after all budesonide treatments compared with placebo (P = .024), but there was no difference between the 3 doses. There was a progressive increase in the allergen PC15 chronologically (sequence effect) that was not explained by improvement in FEV1 or airway responsiveness; sequence effects were not seen for FEV1 or for pretreatment or posttreatment methacholine PC20. Statistical adjustment for sequence effect did not alter allergen PC15 statistics.

CONCLUSION

A 7-day course of budesonide administered by means of Turbuhaler at 200, 400, or 800 microg per day provided marked and significant inhibition of the allergen-induced early asthmatic response compared with placebo. There was, however, no difference between the 3 doses. Therefore this method with these doses is not useful for providing assessment of relative potency.

A multivariate model for predicting respiratory status in patients with chronic obstructive pulmonary disease

OBJECTIVE

To develop and validate a multivariate model for predicting respiratory status in patients with advanced chronic obstructive pulmonary disease (COPD).

DESIGN

Prospective, double-blind study of peak flow monitoring.

SETTING

Albuquerque Veterans Affairs Medical Center.

PATIENTS

Male veterans with an irreversible component of airflow obstruction on baseline pulmonary function tests.

MEASUREMENTS

This study was conducted between January 1995 and May 1996. At entry, subjects were instructed in the use of the modified Medical Research Council Dyspnea Scale and a mini-Wright peak flow meter equipped with electronic storage. For the next 6 months, they recorded their dyspnea scores once daily and peak expiratory flow rates twice daily, before and after the use of bronchodilators. Patients were blinded to their peak expiratory flow rates, and medical care was provided in the customary manner. Readings were aggregated into 7-day sampling intervals, and interval means were calculated for dyspnea score and peak expiratory flow rate parameters. Intervals from all subjects were then pooled and randomized to separate groups for model development (training set) and validation (test set). In the training set, logistic regression was used to identify variables that predicted future respiratory status. The dependent variable was the log odds that the subject would attain his highest level of dyspnea in the next 7 days. The final model was used to stratify the test set into "high-risk" and "low-risk" categories. The analysis was repeated for 3-day intervals.

MAIN RESULTS

Of the 40 patients considered eligible for study, 8 declined to participate, 4 could not master the technique of peak flow monitoring, and 6 had no fluctuations in their dyspnea level. The remaining 22 subjects form the basis of this report. Fourteen (64%) of the latter completed the 6-month protocol. Data from the 8 who were dropped or died were included up to the point of withdrawal. For 7-day forecasts, mean dyspnea score and mean daily prebronchodilator peak expiratory flow rate were identified as predictor variables. The adjusted odds ratio (OR) for mean dyspnea score was 2.71 (95% confidence interval [CI] 1.79, 4.12) per unit. For mean prebronchodilator peak expiratory flow rate, it was 1.05 (95% CI 1.01, 1.09) per percentage predicted. For 3-day forecasts, the model was composed of mean dyspnea score and mean daily bronchodilator response. The ORs for these terms were 2.66 (95% CI 2.06, 3.44) per unit and 0.980 (95% CI 0.962, 0.998) per percentage of improvement over baseline, respectively. For a given level of dyspnea, higher pre-bronchodilator peak expiratory flow rate and lower bronchodilator response were poor prognostic findings. When the models were applied to the test sets, "high-risk" intervals were 4 times more likely to be followed by maximal symptoms than "low-risk" intervals.

CONCLUSIONS

Dyspnea scores and certain peak expiratory flow rate parameters are independent predictors of respiratory status in patients with COPD. However, our results suggest that monitoring is of little benefit except in patients with the most advanced form of this disease, and its contribution to their management is modest at best.

Patient compliance with peak flow monitoring in chronic obstructive pulmonary disease

BACKGROUND

The factors affecting patient compliance with peak flow monitoring in advanced chronic obstructive pulmonary disease (COPD) were examined using a prospective, blinded study.

METHODS

Twenty-eight male veterans were instructed in the use of an electronic, hand-held peak flow meter and the modified Medical Research Council dyspnea scale. They then entered a 6-month monitoring phase in which they recorded a dyspnea score once daily and peak expiratory flow rates twice daily, before and after bronchodilator use. The meter displays were disabled so that the patients were blinded to their values. Medical care was provided in the customary manner. Compliance was defined as the ratio of recorded values to all values specified by the protocol, exclusive of those missing due to circumstances beyond the patient's control.

RESULTS

Of 40 patients who met the entry criteria for this study, 8 refused to participate and 4 could not master the technique. The remaining 28 patients were enrolled. Overall, 25 (63% of those eligible) adhered to the protocol until its conclusion or until they became unable to comply because of medical or social problems. Compliance was 89.8+/-15.0%. Of those followed for longer than 150 days, linear regression showed that only one patient had a decline in compliance over time (r=0.84, P=0.04). Compliance was lower in the afternoons (P < 0.001) and on days with higher dyspnea scores (P < 0.001). No other clinical factors had an effect on patient measurements.

CONCLUSIONS

A substantial proportion of patients with advanced COPD can be trained in the technique of peak flow monitoring. Compliance is high if patients are enrolled in a long-term, structured program of supervision and periodic retraining.

Pharmacologic therapy of asthma during pregnancy

Asthma is a common, potentially serious medical complication during pregnancy. Optimal clinical and pharmacologic management is necessary to mitigate maternal and fetal complications. Mild asthma may be managed in most cases with inhaled beta 2-mimetics. Anti-inflammatory therapy is recommended for the treatment of moderate and severe asthma. Based on limited human experience, beclomethasone is currently the recommended inhaled corticosteroid during pregnancy. However, other inhaled corticosteroids may have advantages compared to beclomethasone because of reduced systemic absorption, which may adversely affect intrauterine growth. Based upon theoretic considerations, theophylline is now considered a secondary therapy, but data demonstrating the superiority of inhaled corticosteroids versus theophylline during pregnancy are lacking.

Specific immunotherapy with Dermatophagoides pteronyssinus and D. farinae results in decreased bronchial hyperreactivity

To evaluate the tolerability and efficacy of specific immunotherapy with mite extracts, we performed a double-blind, placebo-controlled immunotherapy study in 30 patients with proven allergy to mite allergens. The specific immunotherapy with standardized extracts of Dermatophagoides pteronyssinus and D. farinae by a clustered rush protocol was well tolerated. After 1 year of treatment, the actively treated group showed a significant improvement compared to their starting value as well as to the placebo-treated patients with regard to skin prick test, conjunctival provocation test, and subjective rhinitis score. The subjective asthma score and bronchial hyperreactivity, measured by the methacholine provocation test, was improved in comparison to the starting value, but not to the placebo group, after 12 months. However, a further, open comparison of the placebo- and verum-treated groups at 18 months revealed a significant reduction. The drug intake was not increased in the verum-treated group. Exposure to mite levels was constant throughout this time period, as revealed by antigen measurement. We conclude that specific immunotherapy in perennial, mite-allergen-induced asthma may reduce not only immediate, IgE-mediated symptoms but, after a rather long time period of 12-18 months, also the inflammatory component of bronchial asthma, thus leading to a reduction of unspecific hyperreactivity.

Tolerance to the protective effect of salmeterol on allergen challenge

Long-term treatment with inhaled beta 2-agonists may be associated with a deterioration in asthma control, potentially due to tolerance. Regular use of short-acting beta 2-agonists has been shown to induce tolerance to allergen or adenosine 5'-monophosphate challenge. The aim of the study was to detect the efficacy of a single dose and a short-term treatment with salmeterol, a long-acting beta 2-agonist, to protect against early asthmatic reaction (EAR) to allergen. Eight subjects with mild allergic asthma underwent two treatment periods in which subjects performed an allergen challenge (specific bronchial provocation test) protected by a single dose (50 micrograms) of salmeterol (Salm-1) followed by a second specific bronchial provocation test after regular treatment with salmeterol for 1 week (Salm-2), or a single dose of placebo (Plac-1) and regular treatment (1 week) with placebo (Plac-2). Each subject performed both treatments in a randomized order. Each time allergen challenge was performed 1 h after last drug inhalation and it was stopped when the same provocative dose of allergen of a previous screening allergen challenge was achieved. The maximum decrease in FEV1 and area under curve in the first hour after allergen inhalation were significantly lower in Salm-1 (max delta FEV1 %, median [range]: 4%[0 to 9]) with respect to Salm-2, Plac-1, Plac-2 (24%[13 to 38], 31%[19 to 50], 30%[6 to 44], respectively, p < 0.001); there was no difference among Salm-2, Plac-1 and Plac-2. In Salm-1, all subjects were protected against EAR, whereas in Salm-2 only 2 subjects showed a partial protection. In conclusion the protective effect of a single dose of salmeterol against allergen-induced EAR was lost after regular treatment with salmeterol for 1 week. The clinical relevance of this mechanism remains to be elucidated.

Parents' perceptions towards their child's use of inhaled medications for asthma therapy

OBJECTIVE

Understanding patients' and their parents' perceptions towards asthma medication is important in developing strategies to ensure patient compliance. In this study, parents' perceptions towards their children's use of inhaled medication for asthma treatment were evaluated.

METHODOLOGY

A questionnaire was administered by interviewing parents of 210 asthmatic children attending the Department of Paediatrics, National University Hospital.

RESULTS

Our results showed that 76/210 (36%) of parents either felt opposed to inhaler therapy and/or preferred oral medications. The main reasons for their reluctance to use inhalers were related to fear of dependence, side effects and overdosage, and the child's dislike for inhalers. A third of these parents felt that inhalers were only indicated for very severe asthma.

CONCLUSIONS

We conclude that a significant proportion of parents have reservations regarding the use of inhalers for the treatment of asthma. These factors should be taken into consideration when planning an effective asthma education programme.

Relationship between the inflammatory infiltrate in bronchial biopsy specimens and clinical severity of asthma in patients treated with inhaled steroids

BACKGROUND

Current guidelines on the management of asthma advocate the use of anti-inflammatory treatment in all but mild disease. They define disease control in terms of clinical criteria such as lung function and symptoms. However, the relationship between the clinical control of the disease and inflammation of the airways is not clear. A cross sectional study was therefore undertaken to investigate the relationship between airways inflammation and measures of clinical control and bronchial hyperresponsiveness in asthmatic patients treated with inhaled steroids.

METHODS

Twenty six atopic adults (19-45 years) with mild to moderate asthma (baseline forced expiratory volume in one second (FEV1) > or = 50% predicted, concentration of histamine causing a 20% fall in FEV1 (PC20) 0.02-7.6 mg/ml) on regular treatment with inhaled steroids entered the study. Diary card recordings during the two weeks before a methacholine challenge test and bronchoscopic examination were used to determine peak flow variability, symptom scores, and use of beta 2 agonists. Biopsy specimens were taken by fibreoptic bronchoscopy from the carina of the right lower and middle lobes, and from the main carina. Immunohistochemical staining was performed on cryostat sections with monoclonal antibodies against: eosinophil cationic protein (EG1, EG2), mast cell tryptase (AA1), CD45, CD22, CD3, CD4, CD8, CD25, and CD45RO. The number of positively stained cells in the lamina propria was counted twice by using an interactive display system.

RESULTS

There were no differences in cell numbers between the three sites from which biopsy specimens were taken. The PC20 for methacholine was inversely related to the average number of total leucocytes, EG1+, and EG2+ cells, mast cells, CD8+, and CD45RO+ cells in the lamina propria. These relationships were similar for each of the biopsy sites. Symptom scores, beta 2 agonist usage, FEV1, and peak flow variability were not related to any of the cell counts.

CONCLUSIONS

Infiltration of inflammatory cells in the lamina propria of the airways seems to persist in asthmatic outpatients despite regular treatment with inhaled steroids. The number of infiltrating leucocytes such as mast cells, (activated) eosinophils, CD8+, and CD45RO+ cells in bronchial biopsy specimens from these patients appears to be reflected by airway hyperresponsiveness to methacholine, but not by symptoms or lung function. These findings may have implications for the adjustment of anti-inflammatory treatment of patients with asthma.

Effects of immunotherapy on symptoms, PEFR, spirometry, and airway responsiveness in patients with allergic asthma to house-dust mites (D. pteronyssinus) on inhaled steroid therapy

The present study was designed to investigate the effects of immunotherapy (IT) with an extract of Dermatophagoides pteronyssinus (Alergo-Merck Depot) during a 27-month period in patients with allergic asthma to house-dust mites. We included 11 patients (mean age 18 years) treated with a combination of IT and inhaled beclomethasone dipropionate (BDP) in comparison to another 11 (mean age 22 years) treated with BDP alone. We evaluated symptom scores, salbutamol use, peak expiratory flow rates (PEFR), spirometry, and bronchial hyperresponsiveness (BHR) during 18 months of therapy with BDP and in the 9 months after BDP interruption. The two kinds of treatment were efficient and comparable in relation to symptom score, salbutamol use, morning PEFR, FVC, and FEV1, but patients treated with IT and BDP had a faster improvement of BHR and PEFR variability. The interruption of BDP after 18 months of therapy was linked to an impairment of all end points, which were more pronounced in patients previously treated only with BDP. These findings suggest that in selected asthmatic patients allergic to house-dust mites, the association of IT and BDP is more effective than therapy with this inhaled steroid alone due to a faster and more striking improvement during the first months of treatment and to a lower rate of relapse after the interruption of therapy with BDP.

Relationship of non-specific airway hyperresponsiveness (AHR) to measures of peak expiratory flow (PEF) variability

BACKGROUND

The relationship between airway hyper-responsiveness (AHR) and clinical asthma remains controversial and unclear.

AIMS

To test the hypothesis that serial measures of variability of peak expiratory flow rate (PEF) correlate with serial measures of AHR, and to determine which mathematical expression of variability provides the best correlation.

METHODS

A longitudinal study over 180 days of 20 atopic, moderately severe asthmatics was undertaken. A diary of medication use and morning and evening PEFR before and after beta agonist was kept and AHR (PD20 histamine) was measured at three-weekly intervals. Using group data (128 sets) in PD20 was correlated with various measures of PEF variability over 9 days.

RESULTS

[Table: see text] Within the group there was a weak but highly statistically significant correlation between AHR and measures of PEF variability--the strongest correlation being with mean morning PEF. Within individual subjects, however, the correlation was not a consistent finding and only four patients had a statistically significant relationship (p < 0.05) between AHR and mean morning PEF.

CONCLUSIONS

These results suggest that while PEF variability may reflect AHR for the purposes of epidemiologic studies, it is unlikely to be useful as a simple 'non-invasive' means of assessing AHR in individual patients. More complex measures of PEF variability do not have an advantage over simpler measures such as mean morning PEF.

The influence of an inhaled steroid on quality of life in patients with asthma or COPD

Relatively little is known about the influence of inhaled corticosteroids on general well-being (quality of life) in patients with asthma or COPD. In a 4-year prospective controlled study, we examined the influence of beclomethasone dipropionate (BDP), 400 micrograms, two times daily, on quality of life in 56 patients with asthma or COPD in comparison with the effects of BDP on symptoms and lung function. During the first 2 years, patients received only bronchodilator therapy with salbutamol or ipratropium bromide. During the third and fourth years, additional treatment with BDP was given. Fifty-six patients (28 with asthma, 28 with COPD) with an annual decline in the forced expiratory volume in 1 s (FEV1) of at least 80 mL/yr in combination with at least two exacerbations per year during bronchodilator therapy alone participated. Quality of life was assessed at the start and after 2 and 4 years by means of the Inventory of Subjective Health (ISH) and the Nottingham Health Profile (NHP). Although BDP significantly improved the course of lung function (FEV1)(p < 0.0001), it did not improve the ISH score or the six dimensions of the NHP neither in asthma nor in COPD. Beclomethasone dipropionate temporarily decreased respiratory symptoms during months 4 to 6 of BDP treatment in patients with asthma (p < 0.01) and during months 7 to 12 in patients with COPD (p < 0.05). A weak correlation was found both cross-sectionally and longitudinally between (change in) symptoms and quality of life on the one hand, and the (change in) FEV1 on the other. It was concluded that BDP did not improve the general well-being of patients with asthma or COPD as measured by these generic health instruments. However, BDP significantly improved the course of lung function and temporarily decreased the severity of symptoms. It seems probable that changes in quality of life would have been better detected by use of a disease-specific health instrument. Such an instrument was not available at the start of the study. Another possible explanation for these observations is that patients soon get used to different levels of lung function and learn to live with their disease. It is advised that disease-specific health instruments are used in future intervention studies and that quality of life is measured frequently during the early phase of the intervention, eg, once every month.

Peak expiratory flow variation and bronchial hyperresponsiveness in asthmatic children during periods of antigen avoidance and reexposure

Changes of diurnal variation of peak expiratory flow rate (%PEF variation) and their relationship with bronchial hyperresponsiveness (BHR) to methacholine (PC20) were evaluated in 12 children with mild-to-moderate asthma and house-dust mite allergy, during successive periods of stay in a mite-free environment at high altitude (1756 m) and at their home at sea level. The children remained at the high altitude from October until the end of December; then they spent a 3-week period at home and returned to high altitude residence in January. PEF was measured daily, in the morning and in the evening, during the 3 months' stay at high altitude and them for 10 days after the return in January. PC20 was assessed in 8/12 children, once a month from October to December, and at the return in January. Mean absolute PEF values did not change significantly throughout the study. From October to December, patients showed a significant decrease of mean %PEF variation (P = 0.04), while PC20 showed an increase (P = 0.05). After the 3 weeks at home, both %PEF variation (P = 0.03) and PC20 (P = 0.05) significantly worsened. The correlation between PC20 values and mean %PEF variation in the 2 days before and after each methacholine test was r = -0.63 (P = 0.001). Our data suggest that there is a beneficial effect of a prolonged stay in a mite-free environment, on both PEF variability and BHR, also in asthmatic children with good pulmonary function. PEF variability and bronchial responsiveness to methacholine were significantly correlated also for small changes of the two variables.

[Relations between nonspecific bronchial hyperreactivity, diurnal variation of peak expiratory flow and medication requirements in patients with mild asthma]

To assess the relation between non-specific bronchial hyperreactivity, we recorded diurnal peak expiratory flow variation (PFV) and asthma symptoms in 36 individuals with mild allergic asthma. The patients were challenged with methacholine to induce decreases greater than 40% in FEV1, or until a maximum of 200 mg/ml had been administered. Over the next 14 days, PFV was measured three times per day and symptoms and inhaled salbutamol requirements were recorded. In the 11 patients with complete dose-response curves, the geometric mean of diurnal PFV variation (% mean range) was 5.0%; this parameter was 8.3% (p < 0.01) in the 25 subjects whose curves did not reach a plateau. A correlation (r = -0.56, p < 0.001) was found between PC20 and % mean range. PFV for the sample as a whole. In the 11 patients with complete curves, however, no correlation (r = -0.31, p = NS) between % mean range of PFV and PC20 was found. Nor could the plateau (r = 0.19, p = NS) or EC50 (r = -0.26, p = NS) be found for these patients. The geometric mean for PC20 in the 12 subjects who needed salbutamol throughout the 14-day study period after methacholine challenge was 1.06 mg/ml; this parameter was 1.32 mg/ml (p = NS) for those with no symptoms. A plateau was reached by 2 of the 12 patients who experienced asthma symptoms and in 9 of the 24 who were asymptomatic (p = NS).(ABSTRACT TRUNCATED AT 250 WORDS)

Influence of treatment on peak expiratory flow and its relation to airway hyperresponsiveness and symptoms. The Dutch CNSLD Study Group

BACKGROUND

Despite effective treatments, the morbidity and mortality of obstructive airways disease (asthma and COPD) remains high. Home monitoring of peak expiratory flow (PEF) is increasingly being advocated as an aid to better management of obstructive airways disease. The few available studies describing effects of treatment on the level and variation of PEF have involved relatively small numbers of subjects and did not use control groups.

METHODS

Patients aged 18-60 years were selected with PC20 < or = 8 mg/ml and FEV1 < 95% confidence interval of predicted normal. They were randomised to receive, in addition to a beta 2 agonist, either an inhaled corticosteroid (BA+CS), an anticholinergic (BA+AC), or a placebo (BA+PL). One hundred and forty one of these subjects with moderately severe obstructive airways disease completed seven periods of two weeks of morning and afternoon PEF measurements at home during 18 months of blind follow up.

RESULTS

Improvements in PEF occurred within the first three months of treatment with BA+CS and was subsequently maintained: the mean (SE) increase in morning PEF was 51 (8) l/min in the BA+CS group compared with no change in the other two groups. Similarly, afternoon PEF increased by 22 (7) l/min. Diurnal variation in PEF (amplitude %mean) decreased from 18.0% to 10.2% in the first three months of treatment with BA+CS. Within-subject relations between changes in diurnal variation in PEF and changes in PC20 were found to be predominantly negative (median rho-0.40) but with a large scatter. Relations between diurnal variation in PEF and changes in symptom scores, FEV1, and bronchodilator response were even weaker.

CONCLUSIONS

In patients with moderately severe obstructive airways disease, PEF rates and variation are greatly improved by inhaled corticosteroids. Since the relation of diurnal PEF variation with PC20, symptoms, FEV1, and bronchodilator response were all weak, these markers of disease severity may all provide different information on the actual disease state. PEF measurements should be used in addition to the other markers but not instead of them.

Peak expiratory flow meters (PEFMs)--who uses them and how and does education affect the pattern of utilisation?

BACKGROUND

Asthma control may be assisted by educating patients to use peak expiratory flow meters (PEFMs).

AIMS

To find out the sociodemographic and clinical characteristics of asthmatics attending an Emergency Room (ER) who owned PEFMs.

METHODS

We undertook a study of 352 asthmatics aged seven to 55 years who attended an ER. The following were analysed: their pattern of peak flow monitoring (PFM), the factors associated with 'appropriate' or daily PFM on entry to the study and then prospectively; whether asthma education influenced utilisation and whether there was a reduction in ER use or admissions in those who acquired a PEFM.

RESULTS

Those owning a PEFM at entry to the study (54%) had more asthma morbidity (p = 0.0001), had had asthma for longer (p = 0.0001), had seen their medical practitioners more often in the previous nine months (p = 0.0001), were on more asthma medications (p = 0.0001) and were more likely to have been to an Asthma Clinic (p = 0.0001). Those not owning a PEFM were more likely to be of lower social class (p = 0.016) and of Pacific Island origin (p = 0.0001) suggesting that distribution is not ideal and is influenced by disease severity, amount of health care use and sociodemographics. Patients with a self-management plan (35% of PEFM owners) and those receiving 'good care' or management, were more likely to use PFM 'appropriately' and to mention PFM in a scenario evaluating their response to worsening asthma control and argues for PEFMs to be distributed only in conjunction with a self-management plan, and therefore in close association with the patients' medical practitioners. Most patients (75%) appeared to prefer making management decisions based on symptoms rather than on their peak expiratory flow (PEF) and few (16%) performed daily PFM at entry to the study and fewer (6%) nine months later. There was an improvement in the pattern of PFM after education, but the acquisition of a PEFM made no difference to the frequency of ER use or admission.

CONCLUSION

More realistic goals need to be defined in relationship to PFM which may improve patients' acceptance of the strategy, and therefore, hopefully their compliance. Such strategies need to be consistently reinforced over time for them to have an impact on asthma morbidity.