Table 8.

Quality assessment for prognostic factor studies including prognostic models

Study	Representative patient sample?	Loss to follow-up equal in both arms?	Study conducted prospectively (PRO) or retrospectively (RET)?	Samples collected prospectively (PRO) or retrospectively (RET)?	Sampling method: quadrantic biopsy used?	Sample type?	Validated epigenetic technique used?	Epigenetic analysis undertaken blindly? (without knowledge of histology)	Epigenetic analysis undertaken in duplicate?	Was the threshold defined?	Histology undertaken in duplicate?	Histology undertaken blindly? (without knowledge of epigenetic finding)	Were confounding factors described? (eg, obesity, age, smoking, alcohol)	Were confounding factors adjusted for in design or analysis?	Which confounding factors were adjusted for?
Agarwal et al 201246	Unclear	Unclear	PRO	RET	No	Unclear	Yes	Unclear	Unclear	Yes	Unclear	No	Yes	No	N/A
Barrett et al 199937	Yes	Unclear	PRO	RET	No	Snap frozen	Yes	No	Unclear	Unclear	Unclear	Unclear	No	No	N/A
Boerwinkel et al 201443	Yes	Unclear	PRO	RET	Yes	FFPE	Yes	Unclear	Unclear	Yes	Yes	Yes	No	No	N/A
Clément et al 200635	Unclear	Unclear	PRO	RET	No	FFPE	Yes	No	Unclear	Unclear	Unclear	Unclear	No	No	N/A
Clément et al 200834	Unclear	Unclear	PRO	RET	No	FFPE	Yes	No	Unclear	Unclear	Unclear	Unclear	No	No	N/A
Eads et al 200144	Unclear	Unclear	PRO	RET	No	Snap frozen	Yes	Unclear	Unclear	Yes	Unclear	Unclear	No	No	N/A
Jin et al 200941	Unclear	Unclear	RET	PRO	Yes	Snap frozen	Yes	No	Unclear	Yes	No	Yes	Yes	No	N/A
Klump et al 199836	Unclear	Yes	RET	RET	No	FFPE	Yes	No	Yes	Yes	Unclear	No	No	No	N/A
Moinova et al 201242	Unclear	Unclear	Unclear	Unclear	No	FFPE	Yes	No	Unclear	Yes	Unclear	Unclear	No	No	N/A
Revilla-Nuin et al 201333	Yes	Unclear	PRO	Unclear	Yes	FFPE	Yes	No	Unclear	Yes	Yes	Yes	Yes	Unclear	N/A
Puertas Canteria 201245	Unclear	Unclear	Unclear	Unclear	No details	FFPE	Yes	No	Unclear	Unclear	Unclear	No	No	No	N/A
Sato et al 200840	Unclear	Unclear	Unclear	Unclear	Yes	Snap frozen	Yes	No	Unclear	Yes	Yes	Yes	Yes	Yes	BO segment length
Schulmann et al 200539	Unclear	Unclear	RET	Unclear	Yes	Snap frozen	Yes	No	Unclear	Yes	Yes	Yes	Yes	No	N/A
Wang et al 200938	Yes	Unclear	PRO	RET	Yes	FFPE	Yes	No	Unclear	Yes	No	Yes	Yes	No	N/A

BO, Barrett’s oesophagus; FFPE, formalin-fixed paraffin-embedded.