Table 3

Mean (SD) crude estimates of the primary outcomes by pulmonary function laboratory

Laboratory 1 (n=218)Laboratory 2 (n=131)Laboratory 3/4† (n=39)p value‡
A minus sign indicates higher mean laboratory values, absence of a minus sign indicates higher general practice values.
*Combined results of pre-bronchodilator and post-bronchodilator values
†Because of the small number of study subjects (n=7) the results of laboratory 4 have been added to the results of laboratory 3, the laboratory with the next smallest number of subjects.
‡ANOVA test for difference between laboratories.
First year
ΔFEV1*(l)0.078 (0.20)0.053 (0.21)0.078 (0.22)0.286
ΔFVC*(l)0.079 (0.36)0.095 (0.44)0.046 (0.39)0.636
Second year
ΔFEV1*(l)0.082 (0.21)0.016 (0.19)0.036 (0.13)<0.001
ΔFVC*(l)0.086 (0.36)0.095 (0.42)−0.016 (0.25)0.115