Table 5.

Statistical analysis of the influence of time lapse, technical improvements and changes in pathology in the Spigelman score and stage

Dependent factor	Fixed factor*	−2 log likelihood	Significance P value	Estimated effect (95% CI)**	Significance P value	Estimated effect (95% CI)**
			First factor	First factor	Second factor	Second factor
Spigelman score	Time lapse	912.19	<0.001	0.30 (0.24/0.36)/year)
	Scope change 1	1,007.91	<0.001	−2.98 (−4.04/−1.91)
	Scope change 2	995.44	<0.001	−2.60 (−3.35/−1.84)
	Scope change 3	957.54	<0.001	−3.17 (−3.80/−2.54)
	PA change	994.19	<0.001	−3.37 (−4.32/−2.41)
	Time lapse and scope 1 change	908.14	<0.001	0.33 (0.26/0.40)/year	0.07	1.05 (−0.09/2.19)
	Time lapse and scope 2 change	906.04	<0.001	0.36 (0.28/0.43)/year	0.014	1.14 (0.23/2.06)
	Time lapse and scope 3 change	906.47	<0.001	0.24 (0.17/0.31)/year	0.018	−0.98(−1.79/−0.17)
	Time lapse and PA change	903.29	<0.001	0.27 (0.20/0.33)/year	0.003	−1.33 (−2.20/−0.46)
Spigelman stage	Time lapse	562.55	<0.001	0.12 (0.09/0.14)/year
	Scope change 1	648.02	<0.001	−1.17 (−1.62/−0.72)
	Scope change 2	638.99	<0.001	−1.00 (−1.32/−0.68)
	Scope change 3	597.67	<0.001	−1.30 (−1.57/−1.04)
	PA change	627.07	<0.001	−1.47 (−1.87/−1.07)
	Time lapse and scope 1 change	559.12	<0.001	0.14 (0.11/0.17)/year	0.037	0.52 (0.03/1.01)
	Time lapse and scope 2 change	554.80	<0.001	0.15 (0.12/0.18)/year	0.002	0.62 (0.23/1.02)
	Time lapse and scope 3 change	557.95	<0.001	0.09 (0.06/0.12)/year	0.013	−0.44 (−0.80/−0.10)
	Time lapse and PA change	551.20	<0.001	0.10 (0.08/0.13)/year	<0.001	−0.70 (−1.08/−0.33)

* Scope 1 change: the replacement of fibre-endoscopes by video-endoscopes, scope 2 change: the change from EVIS-110 to EVIS-130–140 processors, scope 3 change: the replacement of Low Resolution by High Resolution endoscopes; PA change: replacement of the 4-grade dysplasia ranking by the 3-grade ranking

** CI confidence interval, …/year increase of Spigelman in score or stage per year time lapse