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. 2022 Mar 21;23:67. doi: 10.1186/s12931-022-01990-2

Table 2.

Meta-regression of covariates on prevalence of SAO

Coefficient (% change in prevalence) 95% CI p value
Spirometry parameter
 FEF25–75 (Ref)
 FEF25–75/VC − 14.3 − 38.6, 10.0 0.250
 FEF50/FEF25 9.7 5.9, 13.4 < 0.001
 FEV3/FVC − 5.7 − 9.3, − 2.1 0.002
 FEF50 − 19.3 − 23.1, − 15.6 < 0.001
WHO region
 Americas (ref)
 European 24.3 3.0, 45.6 0.025
 Western Pacific 5.3 3.0, 7.5 < 0.001
 South East Asia 4.1 − 18.7, 26.9 0.726

p < 0.05 = significant. FEF25–75: Mean expiratory flow rate between 25 and 75% of the FVC, FEF25–75/VC: Mean expiratory flow rate between 25 and 75% of the FVC as a ratio of the vital capacity. FEF50: Forced expiratory flow rate at 50% of the FVC. FEF50/FEF25: Forced expiratory flow at 50% of the FVC as a ratio or the forced expiratory flow with 25% of the FVC remaining, FEV3/FVC: forced expiratory volume in 3 s as a ratio of the FVC