Differential effects of maintenance long-acting beta-agonist and inhaled corticosteroid on asthma control and asthma exacerbations

BACKGROUND: Combination therapy with long-acting beta-agonists (LABAs)/inhaled corticosteroids (ICSs) has become established as effective maintenance treatment for asthma. OBJECTIVE: To compare and contrast the efficacy and safety of LABAs/ICSs against different maintenance ICS strategies in adults with asthma. METHODS: Cochrane systematic reviews of randomized controlled trials (to April 2004) were identified that compared the addition of LABA to ICS against 3 inhaled corticosteroid strategies: (1) a similar dose (n = 4312 subjects), (2) a higher dose (n = 4951), and (3) a similar dose in steroid-naive subjects (n = 968). The outcomes evaluated were asthma exacerbations, asthma control, and adverse effects. Pediatric studies were excluded. RESULTS: The addition of LABA to ICSs significantly reduced the risk of exacerbations compared with a similar ICS dose, number needed to treat = 18. The effects of LABA/ICSs on exacerbations compared with the other maintenance inhaled corticosteroid strategies were not statistically significant. LABA added to inhaled corticosteroids led to significant improvements in asthma control compared with all 3 maintenance ICS strategies. There was an increased risk of tremor with LABA/ICSs that reached significance for initial therapy, number needed to harm = 21, and compared with higher ICS doses, number needed to harm = 74. CONCLUSION: Maintenance asthma therapy with LABA/ICSs has differential effects on asthma control and asthma exacerbations. CLINICAL IMPLICATIONS: The greatest benefit and least harm of LABAs comes when they are added to a similar ICS dose in adults with symptomatic asthma.     

The use of inhaled corticosteroids for persistent asthma in infants and young children.

OBJECTIVE: To review pediatric trials of inhaled corticosteroid (ICS) therapy and summarize data on the pediatric use of devices to facilitate delivery of ICSs. DATA SOURCES: Relevant articles regarding ICS treatment of persistent asthma in children younger than 5 years were identified from MEDLINE and reference lists of review articles. STUDY SELECTION: Key articles were selected by the authors. RESULTS: Clinical trials from the United States and Europe consistently demonstrated that ICS therapy is the most favorable treatment option with regard to safety and efficacy for infants and young children with persistent asthma. This contention is supported by numerous trials of budesonide inhalation suspension in children ranging from 6 months through 8 years of age and data from older children treated with fluticasone propionate. CONCLUSIONS: As the only corticosteroid available in the United States as a nebulized formulation and the only ICS product extensively studied in young children and infants, budesonideinhalation suspension is an appropriate first-line therapy for treatment of persistent asthma in this population.     

Safety of inhaled corticosteroids in the treatment of persistent asthma

OBJECTIVE: Inhaled corticosteroids (ICSs) are the most effective medications available for patients with persistent asthma of all severities and currently are recommended as the preferred asthma controller therapy by the National Heart, Lung and Blood Institute. Nevertheless, lingering concerns about potential adverse systemic effects of ICSs contribute to their underuse. This review discusses the safety of ICSs with respect to potential systemic effects of most concern to physicians and patients. METHODS: Articles reporting on the safety of ICSs in children and adults with persistent asthma were identified from the Medline database from January 1966 through December 2003, reference lists of review articles and international respiratory meetings. RESULTS: Ocular effects of ICSs and ICS effects on bone mineral density and adrenal function are minimal in patients maintained on recommended ICS doses. One-year growth studies in children have shown decreased growth velocity with ICSs, but long-term studies with inhaled budesonide and beclomethasone show no effect on final adult height, suggesting that these effects are transient. In addition, extensive data from the Swedish Medical Birth Registry show no increased risk of adverse perinatal outcomes when inhaled budesonide is administered to pregnant women with asthma. CONCLUSIONS: ICSs have minimal systemic effects in most patients when taken at recommended doses. The benefits of ICS therapy clearly outweigh the risks of uncontrolled asthma, and ICSs should be prescribed routinely as first-line therapy for children and adults with persistent disease.     

Inhaled mometasone furoate reduces oral prednisone requirements while improving respiratory function and health-related quality of life in patients with severe persistent asthma

BACKGROUND: Inhaled corticosteroid therapy in severe persistent asthma has been shown to reduce or eliminate oral corticosteroid (OCS) use while retaining effective asthma control. OBJECTIVE: We sought to evaluate the ability of mometasone furoate (MF) delivered by means of dry powder inhaler to reduce daily oral prednisone requirements in OCS-dependent patients with severe persistent asthma. METHODS: We performed a 12-week, double-blind, placebocontrolled trial (21 centers, 132 patients) comparing 2 doses of MF (400 and 800 microg administered twice daily) with placebo, followed by a 9-month open-label phase in which 128 patients received treatment with MF. RESULTS: At the endpoint of the double-blind trial, MF 400 and 800 mg twice daily reduced daily OCS requirements by 46.0% and 23.9%, respectively, whereas placebo increased OCS requirements by 164.4% (P <.01). Oral steroids were eliminated in 40%, 37%, and 0% of patients in the MF 400 and 800 mg twice daily and placebo groups, respectively. Pulmonary function and quality of life significantly increased for MF-treated patients. Further reductions in OCS requirements were achieved with long-term MF treatment in the open-label phase. CONCLUSION: MF inhaled orally as a dry powder is an effective alternative to systemic corticosteroids in patients with severe persistent asthma.     

Inhaled corticosteroids and augmented bronchodilator responsiveness in Latino and African American asthmatic patients.

BACKGROUND: National asthma guidelines recommend that patients with persistent asthma regularly use an inhaled corticosteroid (ICS) in addition to as-needed albuterol, yet recent debates question whether this combination is equally efficacious in all ethnicities. OBJECTIVE: To examine the effect of ICS use on bronchodilator responsiveness to albuterol in 3 different ethnic populations. METHODS: A cross-sectional study of 106 Mexican Americans, 246 Puerto Ricans, and 163 African Americans with physician-diagnosed persistent asthma. Asthma severity, ethnicity, and medication use were evaluated using spirometry and questionnaires. Percentage change in forced expiratory volume in 1 second (FEV) was compared in patients who used ICSs vs those who used a short-acting beta2-agonist as their only asthma medication. RESULTS: Inhaled corticosteroid use was associated with improvements in the percentage change in FEV1 after albuterol administration in Mexican Americans (21.7%, P = .01) and Puerto Ricans (18.5%, P = .02) but not in African Americans (3.0%, P = .73). CONCLUSIONS: Inhaled corticosteroid use is associated with augmented bronchodilator responsiveness to albuterol in Mexican Americans and Puerto Ricans, but not in African Americans, with persistent asthma. This underscores the need for an improved understanding of ethnic-specific drug-drug interactions, particularly in those subgroups experiencing the highest burden of asthma morbidity and mortality in the United States.     

Relationship between adherence to inhaled corticosteroids and poor outcomes among adults with asthma

BACKGROUND: Regular use of inhaled corticosteroids (ICSs) can improve asthma symptoms and prevent exacerbations. However, overall adherence is poor among patients with asthma. Objective To estimate the proportion of poor asthma-related outcomes attributable to ICS nonadherence. METHODS: We retrospectively identified 405 adults age 18 to 50 years who had asthma and were members of a large health maintenance organization in southeast Michigan between January 1, 1999, and December 31, 2001. Adherence indices were calculated by using medical records and pharmacy claims. The main outcomes were the number of asthma-related outpatient visits, emergency department visits, and hospitalizations, as well as the frequency of oral steroid use. RESULTS: Overall adherence to ICS was approximately 50%. Adherence to ICS was significantly and negatively correlated with the number of emergency department visits (correlation coefficient [ R ] = -0.159), the number of fills of an oral steroid ( R = -0.179), and the total days' supply of oral steroid ( R = -0.154). After adjusting for potential confounders, including the prescribed amount of ICS, each 25% increase in the proportion of time without ICS medication resulted in a doubling of the rate of asthma-related hospitalization (relative rate, 2.01; 95% CI, 1.06-3.79). During the study period, there were 80 asthma-related hospitalizations; an estimated 32 hospitalizations would have occurred were there no gaps in medication use (60% reduction). CONCLUSIONS: Adherence to ICS is poor among adult patients with asthma and is correlated with several poor asthma-related outcomes. Less than perfect adherence to ICS appears to account for the majority of asthma-related hospitalizations.     

Omalizumab improves asthma-related quality of life in patients with severe allergic asthma

BACKGROUND: We have previously shown that omalizumab, a recombinant humanized monoclonal anti-IgE antibody, reduces asthma exacerbations and decreases inhaled corticosteroid (ICS) requirement in patients with severe allergic asthma who were symptomatic despite moderate-to-high doses of ICSs. OBJECTIVE: The aim of the present study was to assess the effects of omalizumab on asthma-related quality of life (QOL). METHODS: These analyses were part of a multicenter, 52-week, randomized, double-blind, placebo-controlled study assessing the efficacy, safety, and tolerability of subcutaneous omalizumab (> or =0.016 mg/kg of IgE [in international unit per milliliter] per 4 weeks) in 525 adults with severe allergic asthma. A 16-week steroid-stable phase was followed by a 12-week steroid-reduction phase and a 24-week double-blind extension phase. The effect of treatment on asthma-related QOL was evaluated by using the Asthma Quality of Life Questionnaire (AQLQ) administered at baseline and at weeks 16, 28, and 52. RESULTS: The 2 treatment groups were comparable in terms of baseline AQLQ scores. At weeks 16, 28, and 52, omalizumab-treated patients demonstrated statistically significant improvements across all AQLQ domains, as well as in overall score. Moreover, a greater proportion of patients receiving omalizumab achieved a clinically meaningful improvement in asthma-related QOL during each phase of the study. Greater than 50% of both patients and investigators rated treatment similarly with omalizumab as excellent or good compared with less than 40% of placebo recipients. CONCLUSION: In patients requiring moderate-to-high doses of ICSs for severe allergic asthma, the measurably improved disease control afforded by add-on omalizumab therapy is paralleled by clinically meaningful improvements in asthma-related QOL.     

Immune response to influenza vaccination in children and adults with asthma: effect of corticosteroid therapy

BACKGROUND: Annual influenza vaccination is currently recommended as a preventative measure for all patients with asthma. However, the effect of maintenance corticosteroid therapy on the immune response to influenza vaccine has received limited evaluation. OBJECTIVE: In this study, we evaluated the effect of corticosteroid therapy on the immune response to influenza vaccine in children and adults with asthma. METHODS: This was a substudy of a larger multicenter, randomized, double-masked, placebo-controlled, crossover study investigating the safety of trivalent influenza vaccine in patients with asthma. At baseline, 294 subjects were randomized to receive either placebo first (n=139) or inactivated trivalent split-virus influenza vaccine first (n=155). Study subjects were categorized into 2 groups: subjects in group 1 (n=148) were receiving medium-dose or high-dose inhaled corticosteroids (ICSs) or oral corticosteroids, whereas subjects in group 2 (n=146) were not receiving corticosteroids or were receiving low-dose ICSs. Serum hemagglutination inhibition antibody titers for the vaccine antigens were measured before and 4 weeks after the administration of placebo or vaccine. RESULTS: Serologic responses to each influenza vaccine antigen were significantly higher in vaccine than in placebo recipients and were similar among influenza vaccine recipients in groups 1 and 2 for the following endpoints: rise in antibody titer, percent of participants who developed a serological response, and percent of subjects who developed a serum hemagglutination inhibition antibody titer > or =1:32. Post hoc subgroup analyses demonstrated an attenuated response to influenza B antigen in subjects receiving high-dose ICS compared with subjects who were steroid-na?ve (P<.05). CONCLUSION: The immune response to the A antigens of the inactivated influenza vaccine in subjects with asthma is not adversely affected by ICS therapy. High-dose ICS therapy may diminish the response to the B antigen of the vaccine, an observation that needs further investigation.     

Comparison of single 2000-microg dose treatment vs. sequential repeated-dose 500-microg treatments with nebulized budesonide in acute asthma exacerbations.

BACKGROUND: High repeated doses of inhaled corticosteroids (ICSs) are recognized as having a more rapid improvement of outcomes than a single dose of ICS in severe acute asthma. However, to our knowledge, there has been no direct comparison of the early effects of single or repeated administration of the same total dosage of ICS in children with moderate to severe exacerbations of asthma. OBJECTIVE: To compare the efficacy of a single dose of 2000 microg of nebulized budesonide with 4 repeated doses of 500 microg of nebulized budesonide in 40 children with an acute asthma exacerbation. METHODS: Randomized, double-blind, parallel study that compared the efficacy of 2000 microg of nebulized budesonide, administered in a single dose, with repeated doses (4 doses of 500 microg each) during the first 90 minutes in 40 children (mean [SD] age, 10.7 [2.4] years) with an acute asthma exacerbation that required treatment with an oral corticosteroid. Forced expiratory volume in 1 second, asthma attack score, and oxygen saturation were evaluated at 20, 40, 60, 90, 120, 180, and 240 minutes after initial treatment. Oral corticosteroids were given to all patients at 90 minutes. RESULTS: There were no significant differences in forced expiratory volume in 1 second (P = .54) at any times between the groups. Also, asthma scores and oxygen saturation were not different in either group within 90 minutes (P = .51 and P = .64, respectively) and thereafter (P = .35 and P = .87, respectively). CONCLUSION: The use of a single dose of nebulized budesonide is as effective as repeated administration of the same total dosage during the first 90 minutes before giving oral corticosteroids in children with moderate to severe exacerbations of asthma.     

Response profiles to fluticasone and montelukast in mild-to-moderate persistent childhood asthma

BACKGROUND: Outcome data are needed to base recommendations for controller asthma medication use in school-aged children. OBJECTIVE: We sought to determine intraindividual and interindividual response profiles and predictors of response to an inhaled corticosteroid (ICS) and a leukotriene receptor antagonist (LTRA). METHODS: An ICS, fluticasone propionate (100 mug twice daily), and an LTRA, montelukast (5-10 mg nightly, age dependent), were administered to children ages 6 to 17 years with mild-to-moderate persistent asthma using only as-needed bronchodilators in a multicenter, double-masked, 2-sequence, 16-week crossover trial. Clinical, pulmonary, and inflammatory responses to these controllers were evaluated. RESULTS: Improvements in most clinical asthma control measures occurred with both controllers. However, clinical outcomes (asthma control days [ACDs], the validated Asthma Control Questionnaire, and albuterol use), pulmonary responses (FEV(1)/forced vital capacity, peak expiratory flow variability, morning peak expiratory flow, and measures of impedance), and inflammatory biomarkers (exhaled nitric oxide [eNO]) improved significantly more with fluticasone than with montelukast treatment. eNO was both a predictor of ACDs (P = .011) and a response indicator (P = .003) in discriminating the difference in ACD response between fluticasone and montelukast. CONCLUSIONS: The more favorable clinical, pulmonary, and inflammatory responses to an ICS than to an LTRA provide pediatric-based group evidence to support ICSs as the preferred first-line therapy for mild-to-moderate persistent asthma in children. eNO, as a predictor of response, might help to identify individual children not receiving controller medication who achieve a greater improvement in ACDs with an ICS compared with an LTRA.     

Omalizumab is effective in the long-term control of severe allergic asthma.

BACKGROUND: Previous reports show that addition of omalizumab to standard therapy reduces asthma exacerbations and simultaneously decreases use of inhaled corticosteroids (ICSs) and rescue medication in patients with allergic asthma. OBJECTIVE: To determine the effect of omalizumab on long-term disease control in patients with severe allergic asthma. METHODS: The present study concerns the 24-week, double-blind extension phase to a previous 28-week core study in which patients received subcutaneous omalizumab or matching placebo (at least 0.016 mg/kg/IgE [IU/mL] every 4 weeks) for 16 weeks in addition to their existing ICS therapy (beclomethasone dipropionate [BDP]; steroid-stable phase), followed by a 12-week phase in which controlled attempts were made to gradually reduce ICS therapy (steroid-reduction phase). During the extension phase patients were maintained on randomized treatment (omalizumab or placebo) and the lowest sustainable dose of BDP. The use of other asthma medications was permitted during the extension phase. Investigators were also allowed to switch patients from BDP to other ICS medications if considered necessary. RESULTS: A total of 460 patients (omalizumab, n = 245; placebo, n = 215) entered the extension phase. Overall, omalizumab-treated patients experienced significantly fewer exacerbations vs placebo during the extension phase (0.60 and 0.83 exacerbations per patient, respectively; P = 0.023), despite a sustained significant reduction in their use of ICS (mean BDP equivalent dose: omalizumab, 227 microg/d; placebo, 335 microg/d; P < 0.001). Treatment with omalizumab was well tolerated and the incidence of adverse events was similar in both treatment groups. CONCLUSIONS: These results indicate that omalizumab is effective in the long-term control of severe allergic asthma.     

Therapeutic strategies to reduce asthma exacerbations

Asthma exacerbations can occur in patients with all degrees of asthma severity. They generally develop over 5 to 7 days and are most often initiated by an upper respiratory tract infection (usually with human rhinovirus) or by environmental allergen exposure in atopic subjects. Inhaled corticosteroids (ICSs) taken on a regular basis are very effective in reducing the risk of asthma exacerbations, and the combination of ICSs and long-acting inhaled β?-agonists further reduces this risk. In addition, use of the combination of the ICS budesonide and the long-acting inhaled β?-agonist formoterol, both as maintenance asthma treatment and also as rescue treatment (instead of a short-acting inhaled β?-agonist), has a significant further beneficial effect on asthma exacerbation risk. Other therapies that have been demonstrated to reduce severe asthma exacerbations are leukotriene receptor antagonists, which have been demonstrated to be effective most consistently in this regard in children, and anti-IgE mAbs, which are effective in subjects with difficult-to-treat allergic asthma. Approximately 50% of severe asthma exacerbations are eosinophilic in nature, whereas many of the remaining are neutrophilic. Several studies have demonstrated that making asthma treatment decisions based on minimizing airway eosinophil numbers (measured in induced sputum) can reduce the risks of severe exacerbations. In addition, treatment of patients with severe asthma with an anti-IL-5 mAb also reduces the number of severe asthma exacerbations, demonstrating a central role of eosinophils in many exacerbations.     

Inhaled steroids are associated with reduced lung function decline in subjects with asthma with elevated total IgE

BACKGROUND: Few studies have investigated the long-term association between inhaled corticosteroids (ICSs) and lung function decline in asthma. OBJECTIVE: To evaluate whether prolonged treatment with ICSs is associated with FEV(1) decline in adults with asthma. METHODS: An international cohort of 667 subjects with asthma (20-44 years old) was identified in the European Community Respiratory Health Survey (1991-1993) and followed up from 1999 to 2002. Spirometry was performed on both occasions. FEV(1) decline was analyzed according to age, sex, height, body mass index, total IgE, time of ICS use, and smoking, while adjusting for potential confounders. RESULTS: As ICS use increased, the decline in FEV(1) was lower (P trend = .025): on average, decline passed from 34 mL/y in nonusers (half of the sample) to 20 mL/y in subjects treated for 48 months or more (18%). When adjusting for all covariates, there was an interaction (P = .02) between ICS use and total IgE: in subjects with high (>100 kU/L) IgE, ICS use for 4 years or more was associated with a lower FEV(1) decline (23 mL/y; 95% CI, 8-38 compared with nonusers). This association was not seen in those with lower IgE. CONCLUSION: Although confirming a beneficial long-term association between ICSs and lung function in asthma, our study suggests that subjects with high IgE could maximally benefit from a prolonged ICS treatment. CLINICAL IMPLICATIONS: This study adds further evidence to the beneficial effect of inhaled steroids on lung function in asthma; future studies will clarify whether calibrating the corticosteroid dose according to the level of total IgE is a feasible approach in asthma management.     

The safety of twice-daily treatment with fluticasone propionate and salmeterol in pediatric patients with persistent asthma.

BACKGROUND: For children older than 5 years with asthma who remain symptomatic despite inhaled corticosteroid (ICS) therapy, the preferred treatment is to add an inhaled long-acting beta2-agonist vs increasing the ICS dose. OBJECTIVE: To compare the safety of twice-daily treatment with inhaled fluticasone propionate plus the inhaled long-acting beta2-agonist salmeterol with that of fluticasone propionate used alone in children aged 4 to 11 years with persistent asthma. METHODS: A randomized, multicenter, double-blind, active-controlled, parallel-group study in 203 children with persistent asthma who were symptomatic during ICS therapy. Patients received fluticasone propionate-salmeterol (100/50 microg) or fluticasone propionate (100 microg) alone twice daily for 12 weeks. RESULTS: The safety profile of fluticasone propionate-salmeterol was similar to that of fluticasone propionate alone. The overall incidence of adverse events was 59% for fluticasone propionate-salmeterol and 57% for fluticasone propionate. Both treatments were well tolerated. Two patients receiving fluticasone propionate-salmeterol and 5 receiving fluticasone propionate withdrew from the study because of worsening asthma. Changes in heart rate, blood pressure, and laboratory variables were infrequent and were similar between treatments. No patients had clinically significant abnormal electrocardiographic findings during treatment. Geometric mean 24-hour urinary cortisol excretion at baseline and after 12 weeks of treatment was comparable within and between groups; no patient in either group had abnormally low 24-hour urinary cortisol excretion after 12 weeks of treatment. The incidence of withdrawals due to asthma exacerbations was 2% in the fluticasone propionate-salmeterol group and 5% in the fluticasone propionate group. CONCLUSIONS: In pediatric patients with persistent asthma, fluticasone propionate-salmeterol twice daily was well tolerated, with a safety profile similar to that of fluticasone propionate used alone.     

Sputum eosinophil counts predict asthma control after discontinuation of inhaled corticosteroids

BACKGROUND: Although inhaled corticosteroids (ICSs) are effective in preventing deterioration in asthma control, at least half of subjects with mild-to-moderate asthma will remain stable when these agents are discontinued. OBJECTIVE: We sought to determine whether noninvasive markers of inflammation predict which individuals maintain asthma control after discontinuation of ICSs. METHODS: We analyzed data obtained from 164 subjects with mild-to-moderate asthma who participated in a 16-week trial comparing the effects of continued ICS use with the effects of a switch to salmeterol or placebo. RESULTS: In comparison with continued ICS use, a switch to salmeterol or placebo was associated with increased rates of asthma deterioration over 16 weeks (9.3% vs 24.1% and 37.5%, respectively; P = .04 and P < .001, respectively). We found that neither exhaled nitric oxide nor methacholine PC 20 , when measured at randomization or 2 weeks after randomization, were significant predictors of subsequent asthma control in subjects who discontinued ICSs. However, both induced sputum eosinophil counts measured 2 weeks after a switch from ICS to placebo and changes in sputum eosinophil counts from before cessation of ICSs to after a switch to placebo predicted subsequent asthma deterioration (area under the receiver-operating characteristic curve, 0.771 [ P < .001] and 0.825 [ P < .001], respectively). CONCLUSION: On the basis of a model treatment strategy, we estimate that allocating subjects to ICS therapy on the basis of changes in sputum eosinophil counts after a trial discontinuation could allow 48% of subjects with mild-to-moderate asthma to discontinue ICS therapy without an increased risk of asthma deterioration over a period of at least 14 weeks.     

Impact of long-term inhaled corticosteroid therapy on bone mineral density: results of a meta-analysis.

BACKGROUND: The impact of long-term inhaled corticosteroid (ICS) therapy on bone mineral density (BMD) is poorly understood. OBJECTIVE: To evaluate the impact of long-term ICS use on BMD. METHODS: Random-effects meta-analysis. Published and unpublished literature were identified by searches of MEDLINE and EMBASE databases and consultation with experts. Studies reporting BMD among adult asthma and chronic obstructive pulmonary disease (COPD) patients using ICS and non-ICS controls were identified. Studies selected for review included at least 1 year of follow-up. Two independent reviewers evaluated studies; data from those meeting specified inclusion criteria were abstracted for inclusion in the meta-analysis. RESULTS: Fourteen (5.3%) of 266 reviewed studies met specified inclusion criteria. Sufficient data were available to perform meta-analysis on 3 measures for ICS-using patients (lumbar, femoral neck, and major trochanter BMD) and 1 measure (lumbar BMD) for non-ICS-using controls. Using current National Asthma Education and Prevention Program definitions, the majority of studies (12 of 14) included patients receiving moderate to high doses of ICSs. Among ICS users, annual changes from baseline in lumbar, femoral neck, and major trochanter BMD (-0.23%, -0.17%, and +1.46%, respectively) were not statistically significant. Mean changes in lumbar BMD were also not significantly different from controls (-0.02%). Further, annual changes in lumbar BMD were not statistically significant for subgroups of patients with asthma or COPD. CONCLUSIONS: Long-term use of ICSs in patients with asthma or COPD was not associated with significant changes in BMD.     

Features of severe asthma in school-age children: Atopy and increased exhaled nitric oxide

BACKGROUND: Children with severe asthma have persistent symptoms despite treatment with inhaled corticosteroids (ICSs). The differentiating features of severe asthma in children are poorly defined. OBJECTIVE: To identify features of severe versus mild-to-moderate asthma in school-age children using noninvasive assessments of lung function, atopy, and airway inflammation. METHODS: A total of 75 children (median age, 10 years) with asthma underwent baseline characterization including spirometry and lung volume testing, methacholine bronchoprovocation, allergy evaluation, and offline measurement of exhaled nitric oxide (F(ENO)). Twenty-eight were followed longitudinally over 6 months. Participants were assigned to the severe asthma subgroup if they required high-dose ICS plus 2 or more minor criteria. RESULTS: Children with severe versus mild-to-moderate asthma had more symptoms, greater airway obstruction, more gas trapping, and increased bronchial responsiveness to methacholine. Subjects with severe asthma also had higher concentrations of F(ENO) and significantly greater sensitization to aeroallergens. With long-term study, both the reduction in FEV(1) and increase in F(ENO) persisted in the severe versus mild-to-moderate group. Furthermore, despite adjustments in ICS doses, the frequency of exacerbations was significantly higher in subjects with severe (83%) versus mild-to-moderate asthma (43%). CONCLUSION: Severe asthma in childhood is characterized by poor symptom control despite high-dose ICS treatment and can be differentiated from mild-to-moderate asthma by measurement of lung function and F(ENO). CLINICAL IMPLICATIONS: Clinicians should suspect severe asthma in children with poor response to ICS, airway obstruction, and high F(ENO).     

Pharmaceutical characteristics that influence the clinical efficacy of inhaled corticosteroids.

BACKGROUND: Inhaled corticosteroids (ICSs) are the most effective therapy for the management of persistent asthma. The aim of ICS therapy is to achieve a high anti-inflammatory effect in the airways with a concomitant low risk of unwanted local and systemic effects. Direct estimates of clinical efficacy and potency based on studies in humans are difficult to interpret. OBJECTIVE: To examine the challenges of using alternative estimates of ICS efficacy and potency, including pharmaceutical characteristics. DATA SOURCES AND STUDY SELECTION: Articles published from 1990 to 2002 on the potency, efficacy, and tolerability of ICSs were identified using MEDLINE and in-house databases and were then reviewed. Search terms included inhaled corticosteroid, budesonide, fluticasone, beclomethasone, mometasone, and potency. RESULTS: Differences among ICSs can be readily shown using preclinical measures, such as glucocorticoid receptor binding or skin blanching tests. However, pharmaceutical (delivery and pharmacokinetic) differences of ICSs can have a greater impact on clinical efficacy than in vitro potency differences. For example, the unique esterification of budesonide in the airways prolongs its local activity and may contribute positively to its efficacy and therapeutic index. Although comparative clinical trials suggest 6-fold differences in potencies among ICSs, there is currently no evidence to support differences in efficacy when they are administered at equipotent dosages. CONCLUSIONS: Greater preclinical potency of an ICS does not imply greater clinical efficacy. Pharmacokinetic factors can have a significant impact on relative clinical efficacy.