TABLE 2

Lung function values at P1 and P2 stratified by lung function category and smoking status at P2

	Normal spirometry-P2	PRISm-P2	COPD GOLD 1–4-P2	COPD GOLD 1-P2	COPD GOLD 2–4-P2
Subjects n	970	83	550	355	195
Time between P1 and P2 years	4.6±0.5	4.7±0.43*	4.6±0.4	4.6±0.4	4.6±0.4
FEV₁ % pred					72.1±14.8*
P1	106.2±14.7	82.8±12.8*	88.8±18.2*	97.9±12.6*
P2	106.0±14.2	71.5±7.6*	84.6±18.3*	95.4±10.7*	64.9±11.4*
ΔFEV₁ mL·year⁻¹
All (n=1603)	−39.1 (−65.2– −10.8)	−76.7 (−109.9– −35.0)*	−49.2 (−82.8– −19.1)*	−45.9 (−78.6– −16.9)*	−58.6 (−90.2– −23.6)*
Never-smoker at P2 (n=502)	−42.8 (−72.5– −13.7)	−73.6 (−113.5– −41.61)*	−45.6 (−76.9– −22.9)	−45.9 (−80.0– −23.4)	−43.1 (−75.6– −15.5)
Former smoker at P2 (n=1000)	−37.5 (−61.0– −8.6)	−78.7 (−107.1– −28.01)*	−48.0 (−82.8– −15.4)*	−44.0 (−78.0– −11.2)*	−60.1 (−91.9– −21.9)*
Current smoker at P2 (n=99)	−24.6 (−54.9– −4.9)	−138.4 (−184.0– −96.1)*	−63.0 (−103.1– −40.1)*	−60.1 (−78.6– −40.2)*	−88.4 (−132.7– −36.0)*
FVC % pred
P1	102.4±13.8	80.1±11.8*	95.7±15.5*	102.9±12.1	82.6±12.1*
P2	105.3±14.3	72.1±8.9*	100.7±17.2*	109.7±12.3*	84.4±12.0*
ΔFVC mL·year⁻¹
All (n=1603)	−19.8 (−56.8–20.5)	−66.7 (−119.4– −21.5)*	−3.2 (−44.7–43.1)*	9.0 (−33.5–51.7)*	−27.5 (−64.2–29.6)
Never-smoker at P2 (n=502)	−27.8 (−65.5–9.1)	−64.9 (−124.8– −26.9)*	−11.2 (−39.5–28.5)*	−2.0 (−35.1–31.6)*	−20.5 (−47.0–22.4)
Former smoker at P2 (n=100)	−17.7 (−53.6–22.8)	−65.7 (−102.9– −20.6)*	0.0 (−46.3–56.9)*	11.9 (−29.7–63.2)*	−27.2 (−66.5–43.2)
Current smoker at P2 (n=99)	2.4 (−48.3–34.0)	−175.2 (−212.4– −125.3)*	−24.0 (−48.1–17.4)	0.0 (−44.1–26.0)	−43.4 (−68.9–5.5)*

Data are presented as mean±sd or median (interquartile range). P1: phase 1; P2: phase 2; PRISm: preserved ratio impaired spirometry; COPD: chronic obstructive pulmonary disease; GOLD: Global Initiative for Chronic Obstructive Lung Disease; FEV₁: forced expiratory volume in 1 s; FVC: forced vital capacity. *: p<0.05 compared to subjects with normal spirometry.