Table 3.

Effect of covariates on baseline refractive error in study eyes with choroidal neovascularization (CNV) and fellow eyes without CNV using various regression approaches, Comparison of Age-related Macular Degeneration Treatments Trials

Covariates	Standard linear regression model		Mixed model, random intercept (unstructured or compound symmetry)		Marginal model: PROC MIXED with REPEATED unstructured		Marginal model: GEE, working independence		Marginal model: GEE, compound symmetry
	Regression coefficient (SE)	P-value	Regression coefficient (SE)	P-value	Regression coefficient (SE)	P-value	Regression coefficient (SE)	P-value	Regression coefficient (SE)	P-value
Group (study eye vs fellow)	0.15 (0.09)	0.10	0.15 (0.07)	0.03	0.15 (0.07)	0.03	0.15 (0.07)	0.03	0.15 (0.07)	0.03
Age (per year)	0.01 (0.01)	0.20	0.01 (0.01)	0.29	0.01 (0.01)	0.29	0.01 (0.01)	0.21	0.01 (0.01)	0.22
Sex (female vs male)	0.05 (0.10)	0.58	0.05 (0.12)	0.66	0.06 (0.12)	0.62	0.05 (0.10)	0.60	0.05 (0.10)	0.61
Current smoking (yes vs no)	0.21 (0.18)	0.24	0.21 (0.21)	0.33	0.20 (0.21)	0.33	0.21 (0.23)	0.38	0.21 (0.23)	0.37
Geographic atrophy (no vs yes)	0.07 (0.16)	0.64	0.03 (0.15)	0.82	0.04 (0.15)	0.78	0.07 (0.20)	0.71	0.03 (0.19)	0.85
Glaucoma (no v. yes)	0.25 (0.14)	0.08	0.24 (0.17)	0.16	0.25 (0.17)	0.14	0.25 (0.24)	0.31	0.24 (0.24)	0.32

GEE, generalized estimating equation; SE, standard error