TABLE 2.

Effect of the tested covariates on the objective function^a

Covariate tested	Pharmacokinetic parameter	ΔFobj1	Δη1 (%)	ΔFobj2	Δη2 (%)
BW	CL/F	−71	−41	+48	+100
BW	V/F	−13	−63	+18	+165
Age	CL/F	−42	−16	↔
Age	V/F	−5	−43	↔
Sex	CL/F	−33	−17	+18	+15
Sex	V/F	↔
Dosage form	F	↔
Nevirapine	CL/F	−7	↔	+11	+15
Efavirenz	CL/F	↔
Amprenavir	CL/F	↔
Lopinavir	CL/F	↔

^aΔFobj, observed change in the objective function induced by the corresponding covariate after its addition to the base model (ΔFobj1) or its deletion from the intermediate model (ΔFobj2); Δη, percent change in the interindividual variability of the corresponding pharmacokinetic parameter provided by the addition of the tested covariate in the base model (Δη1) or by its deletion from the intermediate model (Δη2); ↔, no change.