For the efficacy question, randomised or quasi randomised controlled trials (RCTs) that compared a screened and unscreened samples of patients with chronic obstructive pulmonary disease and reported morbidity or mortality outcomes, were eligible for inclusion. For the adverse effects question, studies that assessed spirometry testing, in either an office setting or a pulmonary function laboratory, and addressed harms or test characteristics of spirometry in patients, were eligible for inclusion. Studies which included only a population sample without chronic obstructive pulmonary disease or which were isolated case reports of spirometry-induced pneumomediastinum, bronchial obstruction or incarcerated inguinal hernia were excluded.
Studies included for the adverse effects question included participants referred to a pulmonary function laboratory, a general population excluding patients with known respiratory problems, and healthy adults.
Two reviewers independently assessed the studies for inclusion in the review.