Objective: To evaluate toxicity profiles in patients with rheumatoid arthritis (RA) treated either according to an intensive or a conventional treatment strategy approach with methotrexate (MTX) and to study factors associated with MTX related toxicity.
Methods: Data were used from the CAMERA study in which clinical efficacy of an intensive treatment strategy with MTX was more beneficial compared to a conventional treatment strategy approach. In the present study, data on adverse events were compared between the two treatment groups. Logistic regression analyses were used to identify possible associations between factors assessed at baseline and withdrawal due to MTX related adverse events or liver toxicity at follow-up.
Results: Although significantly more patients in the intensive treatment group experienced MTX related adverse events compared to the conventional treatment group, all recorded adverse events were relatively mild. A higher Body Mass Index (BMI) was significantly associated with withdrawal due to MTX related adverse events in the multiple regression analyses. There was a trend towards an association between diminished creatinine clearance and MTX withdrawal. For liver toxicity, increased serum liver enzymes at baseline were associated with liver toxicity during follow-up.
Conclusion: Although the occurrence of adverse events in the intensive treatment group was higher than in the conventional treatment group, the previously observed clinical efficacy of an intensive treatment strategy seems to outweigh the observed toxicity profiles. When starting MTX, attention should be given to patients with a high BMI and those with increased levels of liver enzymes and decreased renal function.