Study selection
The studies we included have to satisfy the inclusion criteria, as
follows: (1) observational studies; (2) studies evaluated the
relationship among ADRB2 polymorphisms (Arg16Gly, Gln27Glu) and
salbutamol responsiveness in asthmatic patients; (3) studies offered
valid data for calculating odds ratio (OR) and 95% confidence interval
(CI); (4) studies reported short-term differences in the percentage
change in FEV1 after salbutamol inhalation; and (5)
human subjects. The following studies were excluded: (1) studies
contained duplicate or unqualified data; (2) review, commentary,
abstract, editorial, case report, letter and conference report; and (3)
studies did not report the details for the assessment of good
responders.