Naik 2010.

Methods	Study design: cost‐effectiveness analysis, Markov model Time horizon: 1 year Currency used, year of study: US dollars (USD), price year 2006
Participants	Analytic perspective: third‐party payer Setting, country of study: primary and secondary care, USA Population: patients with moderate COPD Effectiveness data: exacerbations; tiotropium data from 3 RCTs (Casaburi 2002; Donohue 2002; Vincken 2002), salmeterol data from 2 RCTs (Donohue 2002; Rennard 2001), no treatment (placebo) data from 3 RCTs (Casaburi 2002; Donohue 2002; Rennard 2001) Utility scores: from published RCTs of various treatments. No reference given. Resource use and costs: costs of drugs, hospitalisations, monitoring (laboratory tests) and physician visits. The drug costs and cost of maintenance therapy were based on average wholesale prices. All other costs were from Medicare sources.
Interventions	Intervention: tiotropium 18 μg once daily Control 1: salmeterol 50 μg twice daily Control 2: no treatment
Outcomes	Cost per exacerbation avoided per patient per year. ICERs were calculated as additional cost per patient to prevent one exacerbation, compared with the next most expensive option
Notes	Sensitivity analysis: one‐way sensitivity analysis; the probability of exacerbation, the probability of hospitalisation, the probability of severe exacerbation, and the compliance rate Funding: not stated