Table 3.
Univariate logistic regression to evaluate the association between MTX intolerance and genetic variants.
| Gen (SNP) | Intolerant (bDMARDs Monotherapy) n = 107; n (%) | Tolerant (MTX and bDMARDs Combo Therapy) n = 120; n (%) | p-Value * | OR (IC 95%) | p-Value ** |
|---|---|---|---|---|---|
| Active Transport of MTX | |||||
| RFC-1-G80A GG or AG (vs. AA) | 74 (69.2) | 94 (78.3) | 0.116 | 0.62 (0.34–1.13) | 0.119 |
| MTX Polyglutamate Formation | |||||
| GGH-T401C AA or AG (vs. GG) | 24 (22.4) | 15 (12.5) | 0.048 | 2.13 (1.06–4.29) | 0.035 |
| Folate Cycle and Purine Synthesis | |||||
| MTHFR-C677T AA or AG (vs. GG) | 65 (60.7) | 86 (71.7) | 0.082 | 0.61 (0.35–1.07) | 0.084 |
| MTHFR–A1298C GG or TG (vs. TT) | 99 (92.5) | 111 (92.5) | 0.995 | 1.39 (0.82–2.33) | 0.219 |
| DHFR AA or AG (vs. GG) | 25 (23.4) | 30 (25) | 0.774 | 0.87 (0.48–1.60) | 0.664 |
| SHMT1-c1303C > T GG or AG (vs. AA) | 93 (86.9) | 108 (90) | 0.466 | 0.74 (0.33–1.68) | 0.470 |
| ITPase-C94A AA or AG (vs. GG) | 14 (13.1) | 16 (13.3) | 0.956 | 1.06 (0.50–2.26) | 0.883 |
| MTX Extraction Pump | |||||
| ABCC2-C24T TT or TC (vs. CC) | 52 (48.6) | 75 (62.5) | 0.035 | 0.59 (0.35–1.00) | 0.050 |
| ABCB1-c3434C > T GG or AG (vs. AA) | 81 (75.7) | 95 (79.2) | 0.532 | 0.78 (0.42–1.45) | 0.435 |
| SLC01B1 TT or TC (vs. CC) | 105 (98.1) | 112 (93.3) | 0.107 | 3.75 (0.78–18.1) | 0.099 |
* chi-square test; ** Univariate logistc regression. bDMARDs: biological disease-modifying antirheumatic drugs; CI: Confidence interval; MTX: Methotrexate; OR: Odds Ratio.