Table 6
Author, date and countryPatient groupStudy type (level of evidence)OutcomesKey resultsStudy weaknesses
Turner MO et al, Canada, 199712 of 18 randomised trials (507 patients)Meta-analysisEffect size−0.02 (−0.2 to 0.16)Includes 102 patients with COPD
Cates C and Rowe BH, UK, 20017 of 44 randomised trials (375 patients)Systematic reviewFEV1No significant difference
PEFRNo significant difference
Length of stayNo significant difference