Mahmud 2007.

Methods	Design: 6‐month, randomised, parallel‐group study Setting: the study was conducted in Bangladesh Date of study: not described
Participants	Participants: n = 90 (tiotropium: 47, salmeterol: 43) Baseline characteristics: not described Diagnostic criteria: not described COPD severity: not described Inclusion criteria: not described Exclusion criteria: not described
Interventions	Run‐in period: not described 1. Tiotropium, 18 µg once daily; or 2. Salmeterol 50 µg via twice daily Concomitant medication Short‐acting anticholingeric: no Short‐acting beta2‐agonist: yes Inhaled corticosteroid: yes Long‐acting beta2‐agonist: no Other: methylxanthines “Both groups received beclomethasone 500 μg twice daily + methylxanthines. Patients were allowed to use salbutamol as per need basis".
Outcomes	Outcome parameters being FEV1, health‐related quality of life (HRQoL), baseline dyspnoea index and frequency of COPD exacerbations
Notes	Unable to contact author to obtain additional information
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Randomised. No further information provided.
Allocation concealment (selection bias)	Unclear risk	Not described
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Not described
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Not described
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Not described
Selective reporting (reporting bias)	Unclear risk	Not described