Long acting beta2 agonists for stable chronic obstructive pulmonary disease with poor reversibility: a systematic review of randomised controlled trials

An integrative review of systematic reviews related to the management of breathlessness in respiratory illnesses

BACKGROUND

Breathlessness is a debilitating and distressing symptom in a wide variety of diseases and still a difficult symptom to manage. An integrative review of systematic reviews of non-pharmacological and pharmacological interventions for breathlessness in non-malignant disease was undertaken to identify the current state of clinical understanding of the management of breathlessness and highlight promising interventions that merit further investigation.

METHODS

Systematic reviews were identified via electronic databases between July 2007 and September 2009. Reviews were included within the study if they reported research on adult participants using either a measure of breathlessness or some other measure of respiratory symptoms.

RESULTS

In total 219 systematic reviews were identified and 153 included within the final review, of these 59 addressed non-pharmacological interventions and 94 addressed pharmacological interventions. The reviews covered in excess of 2000 trials. The majority of systematic reviews were conducted on interventions for asthma and COPD, and mainly focussed upon a small number of pharmacological interventions such as corticosteroids and bronchodilators, including beta-agonists. In contrast, other conditions involving breathlessness have received little or no attention and studies continue to focus upon pharmacological approaches. Moreover, although there are a number of non-pharmacological studies that have shown some promise, particularly for COPD, their conclusions are limited by a lack of good quality evidence from RCTs, small sample sizes and limited replication.

CONCLUSIONS

More research should focus in the future on the management of breathlessness in respiratory diseases other than asthma and COPD. In addition, pharmacological treatments do not completely manage breathlessness and have an added burden of side effects. It is therefore important to focus more research on promising non-pharmacological interventions.

Effects of formoterol on exercise tolerance in severely disabled patients with COPD

OBJECTIVE

We wished to evaluate the effects of inhaled formoterol, a long-acting beta(2)-adrenergic agonist, on exercise tolerance and dynamic hyperinflation (DH) in severely disabled chronic obstructive pulmonary disease (COPD) patients.

DESIGN

In a two-period, crossover study, 21 patients with advanced COPD (FEV(1)=38.8+/-11.7% predicted, 16 patients GOLD stages III-IV) were randomly allocated to receive inhaled formoterol fumarate 12 microg twice daily for 14 days followed by placebo for 14 days, or vice versa. Patients performed constant work-rate cardiopulmonary exercise tests to the limit of tolerance (Tlim) on a cycle ergometer: inspiratory capacity (IC) was obtained at rest and each minute during exercise. Baseline and transitional dyspnoea indices (BDI and TDI) were also recorded.

RESULTS

Eighteen patients completed both treatment periods. Formoterol treatment was associated with an estimated increase of 130 s in Tlim compared with placebo (P=0.052): this corresponded to a 37.8% improvement over placebo (P=0.012). Enhanced exercise tolerance after bronchodilator was associated with diminished DH marked by higher inspiratory reserve and tidal volumes at isotime and exercise cessation (P<0.05). There was no significant difference between formoterol and placebo on exercise dyspnoea ratings; however, all domains of the TDI improved (P<or=0.02) following formoterol, compared with placebo.

CONCLUSION

Inhaled formoterol 12 microg twice daily is effective in ameliorating DH, daily dyspnoea and exercise intolerance even in patients with advanced COPD.

Inhaled therapy for stable chronic obstructive pulmonary disease

Bronchodilators (anticholinergic drugs and beta2-agonist drugs) represent the mainstay of chronic obstructive pulmonary disease treatment and can be combined with inhaled corticosteroids for greater efficacy. This review examines the role of short- and long-acting cholinergic drugs, together with that of short- and long-acting beta2-agonist drugs. A brief analysis of the long-term use of corticosteroids in chronic obstructive pulmonary disease is made, with a review of the safety and possible side effects. Combination therapy is more frequently used due to its practicality and capacity to enhance compliance. The main studies on treatment combinations are also analyzed in this paper.

Systematic review of clinical outcomes in chronic obstructive pulmonary disease: beta-agonist use compared with anticholinergics and inhaled corticosteroids

Much controversy surrounds the use of beta-agonists in obstructive lung disease. Regular beta2- agonist use in asthma results in tolerance to its effects and an increase in asthma-related deaths. Less is known about clinical outcomes in chronic obstructive pulmonary disease (COPD). This systematic review and meta-analysis evaluates the long-term effect of beta2-agonist use on severe exacerbations requiring hospitalization or trial withdrawal, respiratory deaths, and total mortality in patients with COPD. Results for beta2-agonists are compared with results for anticholinergics and inhaled corticosteroids. Pooled results from randomized controlled trials show that anticholinergics, such as tiotropium and ipratropium, significantly reduce severe exacerbations and respiratory deaths compared with placebo. Conversely, beta2-agonists increase respiratory deaths, probably because of tolerance that develops to their bronchodilator and bronchoprotective effects. Anticholinergics significantly reduce exacerbations and total mortality compared with beta-agonists. The combination of the two bronchodilators is not more effective than anticholinergics alone in improving long-term clinical outcomes. Inhaled corticosteroids significantly reduce severe exacerbations and the decline in lung function over time, without affecting mortality. In conclusion, inhaled anticholinergic bronchodilators and corticosteroids should be used to improve long-term clinical outcomes in patients with COPD. beta-Agonists increase respiratory deaths in COPD, possibly as a result of poorer disease control.