Adjusted* relationship between selected risk factors for elevated liver enzyme tests among patients with rheumatoid arthritis†
| Covariate | OR (95% CI) |
| MTX (mg/week) | |
| None | 1.0 (referent) |
| 2.5–7.5 | 1.33 (0.88 to 1.99) |
| 10–17.5 | 1.11 (0.76 to 1.62) |
| ⩾20 | 1.41 (0.96 to 2.08) |
| LEF | |
| None | 1.0 (referent) |
| Any dose | 0.83 (0.63 to 1.77) |
| Additional MTX+LEF interaction‡ | |
| No concomitant use | 1.0 (referent) |
| 2.5–7.5 mg MTX+LEF | 2.15 (0.79 to 5.85) |
| 10–17.5 mg MTX+LEF | 2.91 (1.23 to 6.90) |
| ⩾20 mg MTX+LEF | 3.98 (1.72 to 9.24) |
| Anti-TNF use (referent to no use) | 1.15 (0.90 to 1.47) |
| Body mass index | |
| <25 | 1.0 (referent) |
| 25–30 | 1.21 (0.90 to 1.61) |
| >30 | 1.22 (0.92 to 1.62) |
| Current tobacco use | 0.58 (0.40 to 0.82) |
| History of liver disorder | 2.07 (1.38 to 3.08) |
| Number of liver enzyme test blood draws§ | 1.26 (1.05 to 1.52) |
| Alcohol use | |
| None/occasional | 1.0 (referent) |
| 1–3/week | 0.97 (0.72 to 1.31) |
| 1–2/day | 1.97 (1.18 to 3.28) |
*Additional covariates adjusted for but which were not significant included age, gender, duration of disease, number of physician visits, glucocorticoid dose, non-steroidal anti-inflammatory drug use, recent hospitalisation and folate supplementation.
†Defined as alanine aminotransferase or aspartate aminotransferase greater than the upper limit of the laboratory normal.
‡Quantifies the incremental risk of using both MTX and LEF together, on top of the risk of using each alone.
§During observation period.
LEF, leflunomide; MTX, methotrexate; OR, odds ratio; TNF, tumour necrosis factor.