Does the 2013 GOLD classification improve the ability to predict lung function decline, exacerbations and mortality: a post-hoc analysis of the 4-year UPLIFT trial

Table 6 Annual rates of lung function decline in millilitres, (95% confidence intervals), per GOLD stage

Old stage		P-value^*	New stage		P-value^*	Substage		P-value^*
2	47 (44–50)	-	A	44 (38–52)	-	C1	32 (23–42)	-
3	38 (36–41)	<0.001	B	48 (45–52)	0.29	C2	47 (33–60)	0.11
4	26 (21–31)	0.002	C	38 (30–45)	0.01	C3	38 (16–53)	0.43
			D	39 (37–42)	0.74	D1	36 (33–39)	-
						D2	46 (40–52)	0.003
						D3	38 (34–42)	0.04
AIC	-30,229.05			-30,209.08			-30,212.52

^*Wald test of difference with category immediately above. Overall Wald test of equal decline across stages: p < 0.001 for all models. C1/D1: classified in C/D because of lung function impairment; C2/D2: in C/D because of exacerbation history; C3/D3: because of lung function and exacerbation history.

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