The effect of sustained-release aminophylline on exercise-induced asthma

Intermittent versus daily inhaled corticosteroids for persistent asthma in children and adults

BACKGROUND

Daily inhaled corticosteroids (ICS) are the recommended mainstay of treatment in children and adults with persistent asthma. However, often, ICS are used intermittently by patients or recommended by physicians to be used only at the onset of exacerbations.

OBJECTIVES

The aim of this review was to compare the efficacy and safety of intermittent versus daily ICS in the management of children and adults with persistent asthma and preschool-aged children suspected of persistent asthma.

SEARCH METHODS

We searched the Cochrane Airways Group Specialised Register of trials (CAGR) and the ClinicalTrials.gov web site up to October 2012.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) that compared intermittent ICS versus daily ICS in children and adults with persistent asthma. No co-interventions were permitted other than rescue relievers and oral corticosteroids used during exacerbations.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion, methodological quality and extracted data. The primary efficacy outcome was the number of patients with one or more exacerbations requiring oral corticosteroids and the primary safety outcome was the number of patients with serious adverse health events. Secondary outcomes included exacerbations, lung function tests, asthma control, adverse effects, withdrawal rates and inflammatory markers. Equivalence was assumed if the risk ratio (RR) estimate and its 95% confidence interval (CI) were between 0.9 and 1.1. Quality of the evidence was assessed using GRADE.

MAIN RESULTS

Six trials (including one trial testing two relevant protocols) met the inclusion criteria for a total of seven group comparisons. The four paediatric trials (two involving preschool children and two school-aged children) and two adult parallel-group trials, lasting 12 to 52 weeks, were of high methodological quality. A total of 1211 patients with confirmed, or suspected, persistent asthma contributed to the meta-analyses. There was no statistically significant group difference in the risk of patients experiencing one or more exacerbations requiring oral corticosteroids (1204 patients; RR 1.07; 95% CI 0.87 to 1.32; the large confidence interval translates into a risk of exacerbations in the intermittent ICS group varying between 17% and 25%, assuming a 19% risk with daily ICS). Age, severity of airway obstruction, step-up protocol used during exacerbations and trial duration did not significantly influence the primary efficacy outcome. No group difference was observed in the risk of patients with serious adverse health events (1055 patients; RR 0.82; 95% CI 0.33 to 2.03). Compared to the daily ICS group, the intermittent ICS group displayed a smaller improvement in change from baseline peak expiratory flow rate (PEFR) by 2.56% (95% CI -4.49% to -0.63%), fewer symptom-free days (standardised mean difference (SMD) -0.15 (95% CI -0.28 to -0.03), fewer asthma control days -9% (95% CI -14% to -4%), more use of rescue β2-agonists by 0.12 puffs/day (95% CI 0 to 0.23) and a greater increase from baseline in exhaled nitric oxide of 16.80 parts per billion (95% CI 11.95 to 21.64). There was no significant group difference in forced expiratory volume in one second (FEV1), quality of life, airway hyper-reactivity, adverse effects, hospitalisations, emergency department visits or withdrawals. In paediatric trials, intermittent ICS (budesonide and beclomethasone) were associated with greater growth by 0.41 cm change from baseline (532 children; 95% CI 0.13 to 0.69) compared to daily treatment.

AUTHORS' CONCLUSIONS

In children and adults with persistent asthma and in preschool children suspected of persistent asthma, there was low quality evidence that intermittent and daily ICS strategies were similarly effective in the use of rescue oral corticosteroids and the rate of severe adverse health events. The strength of the evidence means that we cannot currently assume equivalence between the two options.. Daily ICS was superior to intermittent ICS in several indicators of lung function, airway inflammation, asthma control and reliever use. Both treatments appeared safe, but a modest growth suppression was associated with daily, compared to intermittent, inhaled budesonide and beclomethasone. Clinicians should carefully weigh the potential benefits and harm of each treatment option, taking into account the unknown long-term (> one year) impact of intermittent therapy on lung growth and lung function decline.

Intermittent versus daily inhaled corticosteroids for persistent asthma in children and adults

BACKGROUND

Daily inhaled corticosteroids (ICS) are the recommended mainstay of treatment in children and adults with persistent asthma. Yet often, ICS are used intermittently by patients or recommended by physicians to be used only at the onset of exacerbations.

OBJECTIVES

The aim of this review was to compare the efficacy and safety of intermittent versus daily ICS in the management of children and adults with persistent asthma and preschool-aged children suspected of persistent asthma.

SEARCH METHODS

We searched the Cochrane Airways Group Specialised Register of trials (CAGR) and the ClinicalTrials.gov website up to December 2011.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) that compared intermittent ICS versus daily ICS in children and adults with persistent asthma. No co-interventions were permitted other than rescue relievers and oral corticosteroids used during exacerbations.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion, methodological quality and extracted data. The primary efficacy outcome was the number of patients with one or more exacerbations requiring oral corticosteroids and the primary safety outcome was the number of patients with serious adverse health events. Secondary outcomes included exacerbations, lung function tests, asthma control, adverse effects, withdrawal rates and inflammatory markers. Equivalence was assumed if the risk ratio (RR) estimate and its 95% confidence interval (CI) were between 0.9 and 1.1.

MAIN RESULTS

Six trials (including one trial testing two relevant protocols) met the inclusion criteria for a total of seven group comparisons. The four paediatric trials (two involving preschool children and two school-aged children) and two adult parallel-group trials, lasting 12 to 52 weeks, were of high methodological quality. A total of 1211 patients with confirmed, or suspected, persistent asthma contributed to the meta-analyses. There was no statistically significant group difference in the risk of patients experiencing one or more exacerbations requiring oral corticosteroids (1204 patients; RR 1.07; 95% CI 0.87 to 1.32). The patients' age, severity of airway obstruction, step-up protocol used during exacerbations and trial duration did not significantly influence the primary efficacy outcome. No group difference was observed in the risk of patients with serious adverse health events (1055 patients; RR 0.82; 95% CI 0.33 to 2.03). Compared to the daily ICS group, the intermittent ICS group displayed a smaller improvement in change from baseline peak expiratory flow rate (PEFR) by 2.56% (95% CI -4.49% to -0.63%), fewer symptom-free days (standardised mean difference (SMD) -0.15 (95% CI -0.28 to -0.03), fewer asthma control days -9% (95% CI -14% to -4%), more use of rescue β(2)-agonists by 0.12 puffs/day (95% CI 0 to 0.23) and a greater increase from baseline in exhaled nitric oxide of 16.80 parts per billion (95% CI 11.95 to 21.64). There was no significant group difference in forced expiratory volume in one second (FEV(1)), quality of life, airway hyper-reactivity, adverse effects, hospitalisations, emergency department visits or withdrawals. In paediatric trials, intermittent ICS (budesonide and beclomethasone) were associated with greater growth by 0.41 cm change from baseline (532 children; 95% CI 0.13 to 0.69) compared to daily treatment.

AUTHORS' CONCLUSIONS

In children and adults with persistent asthma and in preschool children suspected of persistent asthma, intermittent and daily ICS strategies did not significantly differ in the use of rescue oral corticosteroids and the rate of severe adverse health events, neither did they reach equivalence. Daily ICS was superior to intermittent ICS in several indicators of lung function, airway inflammation, asthma control and reliever use. Both treatments appeared safe, but a modest growth suppression was associated with daily, compared to intermittent, inhaled budesonide and beclomethasone. The clinician should carefully weigh the potential benefits and harm of each treatment option, taking into account the unknown long-term (> one year) impact of intermittent therapy on lung growth and lung function decline.

How much theophylline is enough?

Theophylline not only is a bronchodilator but also has other effects (inhibition of mediator release, enhancement of mucociliary clearance, enhancement of diaphragmatic contractility) that are potentially beneficial to asthmatic patients. Recent studies suggest that theophylline pharmacodynamics vary among asthmatic patients. However, on average, most of the total bronchodilatory response occurs at serum theophylline concentrations of 0 to 10 mg/liter. Additional (but less) bronchodilatation occurs at serum theophylline levels between 10 and 20 mg/liter. Pharmacodynamic relationships are not well established for other therapeutic effects of theophylline, such as attenuation of pharmacologically induced bronchoconstriction. An important feature of oral controlled-release theophylline therapy is timing of drug administration. Because airway reactivity increases and airway caliber decreases at night, it has been suggested that the greatest benefit is derived from theophylline when peak serum concentration is reached during the night or the early morning.

Effects of enprofylline and theophylline on exercise-induced asthma

Eight asthmatic out-patients with a history of exercise-induced asthma (EIA) were randomly treated with intravenously administered enprofylline 1.5 mg/kg b.wt., theophylline 5 mg/kg b.wt., and placebo immediately prior to a 6-min exercise provocation in this double-blind crossover comparison. A reduction in peak flow of more than 20% was seen in all patients after placebo pre-treatment. Mean plasma concentrations at the start of the exercise test were 3.3 mg/l and 13.2 mg/l after 20 min infusion of enprofylline and theophylline, respectively. The corresponding figures 25 min later were 2.3 and 11.7, respectively. Maximal fall in peak expiratory flow (PEF) after exercise in percent of pre-exercise PEF was 49% +/- 6% (mean +/- SEM), 39% +/- 6% and 24% +/- 5% after infusion of placebo, enprofylline, and theophylline, respectively. Theophylline produced a statistically significant better protection against EIA compared to enprofylline and placebo. Enprofylline produced a slight protection from EIA not statistically significantly different from placebo.

Advantages and disadvantages of 24-hour theophylline

The general trend in medical therapy toward once-daily administration has not escaped theophylline preparations. Rapid metabolizers, as are found especially among children and smoking adults, may require a more frequent interval than once-a-day dosing, and greater fluctuations in theophylline levels should be expected. An interaction with food has been seen with once- and twice-daily theophylline preparations. Some products release their contents more rapidly while others do so more slowly in association with a high-fat diet. The food effect is of little concern if the theophylline is taken 1 hour before the meal. The greatest anticipated value of once-daily theophylline medications would be improved patient compliance.

Exercise and the asthmatic

Physical exercise is not hazardous to asthmatics. Some asthmatics may benefit from physical training, and almost all asthmatics can perform any kind of physical exercise. Free running was earlier thought to induce more asthma than swimming, for example; however, when ventilation is identical during running and swimming, the exercise-induced asthma will also be the same. Hyperventilation alone is as good as physical exercise to induce exercise-induced asthma. If the physical exercise provokes an asthmatic attack, this is most often easily reversed by inhaled beta 2-agonists. Pretreatment of exercise-induced asthma is most efficient by inhaled beta 2-agonist; orally dosed beta 2-agonist is not as efficient as inhaled beta 2-agonist in the pretreatment of exercise-induced asthma. Inhaled sodium cromoglycate diminishes exercise-induced asthma, and the effect seems to be better in children than in adults. Inhaled steroids have no immediate effect on exercise-induced asthma, but long term treatment with steroids diminishes exercise-induced asthma. The pathogenesis of exercise-induced asthma remains obscure. If the water content is low in the inhaled air, e.g. in cold air, the changes in ventilatory capacity following exercise. will be greater than when the exercise is performed while inhaling hot air with high humidity. Almost all asthmatics present changes in the ventilatory capacity following exercise. Seasonal changes in exercise-induced asthma are only present in asthmatics with seasonal allergies, e.g. pollen allergy. No diurnal variation is found in exercise-induced asthma. Asthmatics can do any form of physical exercise. Almost all asthmatics can prevent major changes in ventilatory capacity by pretreatment of exercise-induced asthma or be treated for exercise-induced asthma during the physical activity so that they will not suffer from asthma while performing physical exercise. Asthmatics who have been successfully treated for exercise-induced asthma can do physical exercise at the same level as non-asthmatics. Asthmatic children in particular should be encouraged to perform any sport they like, as the physiological and psychological effects may be beneficial to them. It is concluded that almost all asthmatics have exercise-induced asthma, and that physical training may be beneficial. Exercise-induced asthma is best treated and pretreated by inhalation of beta 2-agonists.