Table 3.

Effect of APOE ϵ4 Allele, Total Cholesterol, and Human Immunodeficiency Virus Infection on the Rate of Cognitive Decline

Model	Estimate	SE	P Value
Model 1a (n = 542)
HIV+* Years in study	−0.0104	0.0168	.266
HIV+* Years in study* Years in study	0.0002	0.0016	.003
APOE ε4 carrier* Years in study	0.0227	0.0243	.022
APOE ε4 carrier* Years in study* Years in study	−0.0008	0.0022	.002
HIV+* APOE ε4 carrier* Years in study	0.0519	0.0355	.300
HIV+*APOE ε4 carrier* Years in study* Years in study	−0.0106	0.0035	.010
Model 2b (n = 245)
APOE ε4 carrier* Years in study	−0.02388	0.06127	.8136
HIV+* Years in study	0.1452	0.04568	.0005
Total cholesterol (10 mg/dL)* Years in study	0.00214	0.00125	.8417
Total cholesterol (10 mg/dL)* HIV+* Years in study	−0.0056	0.00184	.0021
APOE ε4 carrier* HIV+* Years in study	0.0266	0.07136	.71
APOE4 carrier* HIV+* Years in study* Years in study	−0.01099	0.003421	.0058
APOE ε4 carrier* Total cholesterol (10 mg/dL)* Years in study	0.00192	0.00252	.3598
APOE ε4 carrier* HIV+* Total cholesterol (10 mg/dL)* Years in study	−0.00004	0.000308	.897

All models were adjusted for age, Shipley WAIS IQ-Equivalent Score, Center for Epidemiological Studies Depression Scale at study entry, smoking status, and CD4 count. Total cholesterol was interpreted in 10 mg/dL increments. APOE ε4 was modeled as a categorical variable (ϵ4 carrier, ϵ4 noncarrier or unknown/ϵ2 homozygous) in model 1. Model 2 included subjects with known APOE ϵ4 genotype.

R² is the squared Pearson correlation between predicted values from fixed or fixed and random effects vs actual values and represents the variance in the cognitive summary score accounted for by terms in the model.

Abbreviations: APOE, apolipoprotein E; HIV⁺, human immunodeficiency virus infected; SE, standard error.

^a Model 1: R² for fixed effects = 0.26, P < .001; R² including random terms = 0.97, P < .0001.

^b Model 2: R² for fixed effects = 0.28, P < .001; R² including random terms = 0.93, P < .0001.

* Indicates an interaction.