Ref (type)	Population	Outcome, Interventions	Results and statistical analysis	Effect size	Favours
Adverse effects
[30] Systematic review	538 people 2 RCTs in this analysis	Proportion of people withdrawing from a study because of adverse effects with ipratropium with salmeterol Absolute results not reported	OR 0.45 95% CI 0.07 to 2.95 P = 0.40		Not significant
[30] Systematic review	703 people 2 RCTs in this analysis	Proportion of people withdrawing from a study because of adverse effects with ipratropium with formoterol Absolute results not reported	OR 1.84 95% CI 0.64 to 5.31 P = 0.26		Not significant
[45] Systematic review	1365 people 4 RCTs in this analysis	Proportion of people withdrawing from a study because of adverse effects 30/682 (4%) with ipratropium 21/683 (3%) with salmeterol	RR 1.42 95% CI 0.82 to 2.45 P = 0.2 Further details on types of adverse effect associated with treatments not reported		Not significant
[45] Systematic review	1365 people 4 RCTs in this analysis	Proportion of people reporting an adverse effect 365/682 (53.5%) with ipratropium 363/683 (53.1%) with salmeterol	RR 1.00 95% CI 0.91 to 1.10 P = 1 Further details on types of adverse effect associated with treatments not reported		Not significant