Table 3.

NONMEM regression parameters.

Parameter	Population estimate	s.e.*
Θ1 (CL, age)	0.1571 l h−1	0.0365
Θ2 (V, weight)	0.2176 l kg−1	0.0235
Θ3 (KA)	0.3130 h−1	0.0578
Θ4 (CL, weight)	0.0028 l kg−1 h−1	0.0005
Θ5 (F1 bioav.)	0.9194	0.0185
Θ6 (CL, age)	−0.5169	0.0165
Θ7 (CL, gender)	0.0342 l h−1	0.0173
Sulphasalazine	0.0652	0.0263	delta†: 13.8
Gold	−0.0280	0.0214	delta†: 4.0
Corticosteroids	−0.0426	0.0193	delta†: 9.9

CL = Θ₁. (AGE/50)^Θ6 + Θ₄. WGT + Θ₇. (1-SEX), V = Θ₂. WGT. KA = CL/V + Θ₃. F1 = Θ₅. (1-OCC) + OCC.

^*s.e., estimated asymptotic standard error of the parameter.

^†Delta, difference in NONMEM objective function with and without inclusion of the covariate, c(P < 0.05) = 3.84.