Study	Reason for exclusion
Ando 2008	Evaluated the effects of tiotropium alone vs LABA/ICS combination
Bateman 2008	Evaluated the effects of tiotropium alone vs LABA/ICS combination
Biscione 2009	Treatment period: 4 weeks
Golabi 2006	Evaluated the effects of tiotropium alone vs LABA/ICS combination
Hara 2007	Evaluated the effects of tiotropium alone vs LABA/ICS combination
Maltais 2013	Time of follow up was less than 8 weeks; treatment period for triple therapy was just 4 weeks
Perng 2006	Treatment period: 4 weeks
Petroianni 2008	Evaluated effects of tiotropium alone vs formoterol alone
Sarac 2013	Assessed for effects of tiotropium alone vs LABA/ICS combination
Singh 2008	14 days of treatment and of cross‐over design
Tashkin 2008	Evaluated tiotropium vs placebo; co‐treatment allowed
Troosters 2008	Evaluated tiotropium vs placebo; co‐treatment allowed

ICS: inhaled corticosteroids

LABA: long‐acting beta‐agonists