Introduction
Potential hepatotoxicity associated with disease modifying anti-rheumatic drugs [DMARDs] requires laboratory monitoring. In rheumatoid and psoriatic arthritis [RA, PsA] patients, we examined the incidence of elevated alanine/aspartate aminotransferase (ALT/AST) enzymes associated with methotrexate (MTX), leflunomide (LEF), and MTX+LEF vs. other DMARDs.
Methods
RA and PsA patients enrolled in the Consortium of Rheumatology Researchers of North America (CORRONA) initiating DMARDs were identified. Abnormalities were identified when either was 1 or 2-fold time above the upper limits of normal (ULN). Odds ratios [OR] between MTX/LEF dose and elevated ALT/AST enzymes were estimated using generalized estimating equations. Interaction terms for use of MTX+LEF quantified the incremental risk of the combination compared to each individually.
Results
Elevated ALT/AST levels (>1× ULN) occurred in 22, 17, 31, and 14% RA patients receiving MTX, LEF, MTX+LEF, or neither, respectively; elevations were 2.76 fold (95% CI 1.84 – 4.15) more likely in PsA patients. Elevations > 2× ULN occurred in 1–2% of patients on MTX or LEF monotherapy compared to 5% with the combination. After multivariable adjustment and compared with either monotherapy, combination MTX + LEF was associated with greater risk according to MTX dose used as part of the combination: MTX 10–17.5mg/week, OR=2.91 (95% confidence interval [CI] 1.23–6.90) and MTX ≥20 mg/week, OR=3.98 (95% CI: 1.72–9.24).
Conclusions
14–35% of RA and PsA patients initiating DMARD therapy developed abnormal ALT/AST levels. Risks were incrementally greater in those with PsA and in those receiving MTX (≥ 10mg/day) + LEF. These findings should help inform monitoring for potential hepatotoxicity in these patient populations.
Psoriatic arthritis (PsA) is a chronic inflammatory arthropathy characterized by the association of arthritis and psoriasis. PsA runs a variable course, from mild synovitis to severe, progressive, erosive arthropathy. The pathogenesis of PsA involves alteration in the components of the immune response, although the exact cause of PsA is unknown. A number of patients with severe peripheral arthritis fail to respond to standard conventional therapy. Advances in biotechnology and in our understanding of the immunopathogenesis of PsA have led to great interest and progress in regards to biologic treatments for PsA. Notable success achieved with recently introduced biologic therapies has paved the way for further research and develpoment of additional therapies that should improve outcomes for affected patients.
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