Table 3.

Results of meta-regression

	Coefficient (95% CI)	Standard error	p-value	Adj. R-squared
Mean age	1.008 (0.973–1.045)	0.015	0.595	− 30.15%
Mean BMI	1.004 (0.927–1.088)	0.033	0.901	− 40.77%
Female percentage (%)	0.994 (0.965–1.023)	0.012	0.617	− 2.00%
Current smoker percentage (%)	1.004 (0.996–1.012)	0.003	0.285	− 13.65%
Smoking pack-years	1.013 (1.001–1.024)	0.004	0.038	97.54%
Follow-up years	0.795 (0.627–1.007)	0.077	0.055	89.52%
Pre- or post-bronchodilation	1.218 (0.829–1.788)	0.198	0.265	31.99%
Study year	0.962 (0.866–1.070)	0.043	0.420	4.94%