Table 2.

Interpretation of the fixed effects coefficients from a linear mixed effects model assessing associations of APOL1 genotype with eGFR measured repeated over time

VariableaCoefficient InterpretationCoefficient EstimateCoefficient SEMP Value
APOL1 high riskDifference in average baseline eGFR (milliliters per minute per 1.73 m2) among African ancestry participants with APOL1 high-risk alleles compare with whites−2.951.050.005
APOL1 low riskDifference in average baseline eGFR (milliliters per minute per 1.73 m2) among African ancestry participants with APOL1 low-risk alleles compare with whites−3.770.62<0.001
YearsAverage eGFR slope (milliliters per minute per 1.73 m2 per year) among whites−0.74−0.07<0.001
Years × APOL1 high riskDifference in average eGFR slope (milliliters per minute per 1.73 m2 per year) among African ancestry participants with APOL1 high-risk alleles and whites−1.500.20<0.001
Years × APOL1 low riskDifference in average eGFR slope (milliliters per minute per 1.73 m2 per year) among African ancestry participants with APOL1 low-risk alleles and whites−0.580.11<0.001
  • Results are the estimated fixed effects from a random slope model fit for the Chronic Renal Insufficiency Cohort Study example in model 2.

  • a Model 2: Embedded Image APOL1 is the exposure variable of the genotype in conjunction with race with three categories (0, white; 1, APOL1 low risk; and 2, APOL1 high risk), with whites as the reference group. The random effects include both random intercept and random slope to account for subject-specific deviation from the population-average trajectory.