Table 7.

GRADE Assessment of Studies Included in Meta-analysis of Alcohol Use and Open-Angle Glaucoma

		Factors That Can Reduce the Quality of the Evidence					Factors That Can Increase the Quality of the Evidence
Number of Studies	Design∗	Study Limitations†	Inconsistency‡	Indirectness§	Imprecision‖	Publication Bias¶	Large Magnitude of Effect#	Dose–response Effect	Plausible Effect of Residual Confounding∗∗	Overall Quality of Evidence
11 (173 058 participants)	Observational	High	Present	None	None	None	None	None	Present	⊕○○○
Evidence	Low	−1	−1	0	0	0	0	0	+1	Very low

^∗Observational studies are assigned a default “low” level of evidence, which can then be downgraded or upgraded further according to various factors.

^†Assessed using a Risk of Bias tool designed for nonrandomized studies of exposures (Fig S4, available at www.aaojournal.org). Downgraded 1 level due to “critical” limitation in 1 domain.

^‡Criteria for significant inconsistency of results were I² > 50% or P < 0.10 for the chi-square test of heterogeneity.

^§All studies assessed the association between self-reported alcohol consumption and a diagnosis of open-angle glaucoma.

^‖Not downgraded due to large sample size and 95% confidence intervals excluding no effect.

^¶The possibility of publication bias is not excluded but it was not considered sufficient to downgrade the quality of evidence.

^#Defined as effect estimate >2.0 or <0.50, based on direct evidence with no plausible confounders.

^∗∗Sensitivity analysis revealed significant heterogeneity between studies reporting unadjusted and adjusted effect estimates, with the suggestion that further adjustment would result in a stronger effect.