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Table 4 Stepwise covariate analysis

From: The effect of age on CD4+ T-cell recovery in HIV-suppressed adult participants: a sub-study from AIDS Clinical Trial Group (ACTG) A5321 and the Bone Loss and Immune Reconstitution (BLIR) study

Parameter Covariate P value Coefficient
Forward Addition (α = 0.05)
 σ [(cell/μL) • year− 1] No significant covariates NA NA
 dN (year • cell/μL)− 1 Age < 0.001 0.0467
 dM (year • cell/μL)− 1 Sex (Female) 0.0039 −0.510
Smoking Status (No prior smoking history) 0.019 0.573
 α (year− 1) Age 0.046 0.0203
%Activated CD4+ T-cells 0.042 0.228
 baselineN (cell/μL) Viral load (log10RNA/mL) < 0.001 −0.636
%Activated CD4+ T-cells 0.015 −0.446
 baselineM (cell/μL) Viral load (log10RNA/mL) < 0.001 −0.388
%Activated CD4+ T-cells < 0.001 −0.396
%Activated CD8+ T-cells 0.0091 0.249
Backward Elimination (α = 0.01) P value IIV (%)  
 σ [(cell/μL) • year−1] No significant covariates < 0.01 NA NA
 dN (year • cell/μL)−1 Age −9.6 0.0389
 dM (year • cell/μL)−1 Sex (Female) −5.0 −0.597
 α (year−1) No significant covariates NA NA
 baselineN (cell/μL) Viral load (log10RNA/mL) −20 −0.648
 baselineM (cell/μL) Viral load (log10RNA/mL) −17.3 −0.422
%Activated CD4+ T-cells −8.3 −0.378
  1. σ: production rate of naïve T-cells, α: activation rate constant of naïve T-cells that acquire a memory phenotype, dN: naïve T-cell death rate constant, dM: memory T-cell death rate constant, baselineN: naïve T-cell count at ART initial, baselineM: memory T-cell count at ART initial, IIV: inter-individual variability, NA: not applicable. Parameter-covariate relations are described using a linear function, e.g. Pi = P • (1+ b * age), with Pi as the individual value, P as the population value and b as the covariate coefficient. Immune activation, presented as %CD38+/HLA-DR+ on the cells, are log-transformed