Table 5.
Multivariate analysis considering for each pharmacological dependent variable covariate significant in the univariate analysis.
| Azathioprine Related Pharmacological Phenotype (Dependent Variable) | Independent Variable in Multivariate Generalized Linear Model | Comparison | Effect | p-Value |
|---|---|---|---|---|
| Efficacy of azathioprine at the first metabolite measurement | IBD type | UC versus CD | 1.96 | 0.0019 |
| GSTM1 genotype | Deletion versus Normal | −1.49 | 0.019 | |
| GSTA1 genotype | AA versus GG/GA | −1.30 | 0.095 | |
| TPMT genotype | AG versus GG | 24.7 | 0.43 | |
| TGN metabolites concentrations | IBD type | UC versus CD | 0.061 | 0.074 |
| TPMT genotype | AG versus GG | 0.23 | 0.0049 | |
| MMPN metabolites concentration | GSTM1 genotype | Deletion versus Normal | −0.21 | 0.014 |
| TPMT genotype | Heterozygous versus wild-type | −0.72 | 0.0004 | |
| Azathioprine dose | Age | Each year | −0.035 | <0.0001 |
| TPMT genotype | Heterozygous versus wild-type | −0.58 | 0.0056 | |
| Ratio TGN/dose | TPMT genotype | Heterozygous versus wild-type | 0.41 | 0.0001 |
| GSTM1 genotype | Deletion versus Normal | −0.072 | 0.055 |
GST: glutathione-S-transferase, IBD: inflammatory bowel disease, UC: ulcerative colitis, CD: Crohn’s disease, MMPN: methylated nucleotides, TGN: thioguanine nucleotides, TPMT: thiopurine-S-methyl transferase. The effect size represents the increase (positive value) or decrease (negative value) in the value of the dependent variable for each independent variable listed. p-values are from linear mixed-effect models.