Level 1: Likely reliable evidence
The addition of multiple doses of inhaled ipratropium (an anticholinergic) to beta2-agonists may reduce the rate of hospital admissions in children and adults with moderate-to-severe asthma exacerbations (Thorax. 2005;60:740-746). This is based on a systematic review of randomized, placebo-controlled trials comparing inhaled anticholinergics plus beta2-agonist vs. beta2-agonist alone. The 32 trials included 3,611 patients. Twenty-nine of the trials evaluated ipratropium bromide, while two trials evaluated oxitropium bromide and one trial evaluated glycopyrrolate.
Ten of the trials reported rates of hospital admission in 1,786 children and adolescents. The rate of hospital admission was 21.5% in the anticholinergic group compared with 29.8% in the control group (P <0.0001, NNT 12, 95% confidence interval [CI] 9-28). In trials that evaluated multiple doses of anticholinergic agents, the NNT was 7 (95% CI 4-16).
Rates of hospital admission for 1,556 adults were reported in nine trials. The rate of admission was 14.2% in the anticholinergic group compared with 21.3% in the control group (P <0.0001, NNT 14, 95% CI 9-30). The NNT was 6 (95% CI 4-13) in trials that evaluated multiple doses of anticholinergic agents.