A Cochrane review [Abstract] 1 included 22 studies. The anticholinergic drugs included ipratropium bromide (7 studies), oxitropium bromide (8), nebulised atropine methonitrate (1) and inhaled atropine sulphate (1). The dose of ipratropium bromide ranged from 40 µg to 200 µg delivered either by metered dose inhaler or powder inhaler. The frequency of administration ranged from twice daily to five times daily. 13 studies (n=205) compared anticholinergics with placebo and 9 studies (n=440) compared the combination of anticholinergics and short acting beta2-agonists with short acting beta2-agonists alone. There were some reservations with respect to the quality of the studies.
Anticholinergic agents in comparison with placebo resulted in more favourable symptom scores particularly in respect of daytime dyspnoea (WMD -0.09, 95% CI -0.14 to -0.04; 3 studies, n=59). There was also a statistically significant improvement in the daily peak flow measurements with the anticholinergic (e.g. morning PEF: WMD 14.38 litres/min, 95% CI 7.69 to 21.08; 3 studies, n=59). However the clinical significance is small and in terms of peak flow measurements equates to approximately a 7% increase over placebo. The combination of anticholinergic plus short acting beta2-agonist versus short acting beta2-agonist alone gave no evidence of any significant differences in respect of symptom scores or peak flow rates between the two regimes.
Comment: The quality of evidence is downgraded by several limitations in study quality, by inconsistency (heterogeneity in patient populations, interventions and outcomes) and by imprecise results (limited study size for each comparison).
Primary/Secondary Keywords