Polymorphic acetylation: lack of influence of rheumatic disease activity and concomitant drug administration

Acetylation polymorphisms have been linked with a tendency to develop rheumatic diseases. We investigated the effect of changes in the disease activity of patients with rheumatoid arthritis (RA) during disease-modifying antirheumatic drug (DMARD) treatment, and on the capacity of these patients to acetylate the sulphonamide sulphadimidine. Fifty-four patients with RA treated with gold, sulphasalazine or D-penicillamine, 12 patients with AS and 16 patients with non-inflammatory arthritis (NI) were investigated over a 24-week period. The capacity of these individuals to acetylate sulphadimidine was determined at baseline and after 12 and 24 weeks. Although there was a tendency for sulphadimidine acetylation to increase in patients with RA from a median of 84.5% [interquartile range (IQR) 77.0-95.0%] at baseline to 90.5% (IQR 77.5-96.0%) at week 24, this failed to reach statistical significance. In contrast, the trend in patients with AS or NI was towards a decrease in acetylation. There was no correlation between changes in disease activity and sulphadimidine acetylation during DMARD intervention.