Table 2

Mean (95% CI) and trimmed mean for crude and adjusted estimates of the primary outcomes

	First year (n=388)				Second year (n=335)
	Crude estimate		Adjusted* estimate		Crude estimate		Adjusted* estimate
		Mean	Trimmed† mean	Mean	Trimmed† mean	Mean	Trimmed† mean	Mean	Trimmed† mean
A minus sign indicates higher mean laboratory values, absence of a minus sign indicates higher general practice values.
*Adjusted for the influence of differential timing between measurements performed in pulmonary function laboratory and general practice.
†Arithmetic mean calculated with exclusion of the largest 5% and the smallest 5% of the values.
‡Combined results of pre-bronchodilator and post-bronchodilator values.
ΔFEV₁ (l)
Pre-bronchodilator		0.079	0.077	0.085	0.083	0.065	0.061	0.072	0.068
	(0.057 to 0.101)		(0.063 to 0.107)		(0.044 to 0.087)		(0.051 to 0.094)
Post-bronchodilator	0.058	0.060	0.065	0.067	0.050	0.044	0.057	0.051
	(0.039 to 0.078)		(0.045 to 0.085)		(0.029 to 0.071)		(0.036 to 0.079)
Pooled‡	0.069	0.069	0.076	0.075	0.058	0.053	0.065	0.060
	(0.054 to 0.084)		(0.061 to 0.091)		(0.043 to 0.073)		(0.050 to 0.080)
ΔFVC (l)
Pre-bronchodilator	0.103	0.102	0.104	0.104	0.091	0.073	0.096	0.078
	(0.062 to 0.143)		(0.064 to 0.144)		(0.049 to 0.133)		(0.054 to 0.138)
Post-bronchodilator	0.056	0.062	0.061	0.068	0.068	0.053	0.074	0.059
	(0.017 to 0.095)		(0.022 to 0.100)		(0.028 to 0.107)		(0.035 to 0.113)
Pooled‡	0.081	0.083	0.084	0.086	0.079	0.063	0.085	0.069
	(0.053 to 0.109)		(0.056 to 0.112)		(0.051 to 0.108)		(0.056 to 0.114)