The effects of sulfasalazine treatment on enthesal abnormalities of inflammatory rheumatic diseases

The aim of this study was to evaluate the effects of a 1-year course of sulfasalazine monotherapy on enthesal abnormalities of inflammatory rheumatic diseases (IRDs) using ultrasonography. Thirty-six patients with IRD including 20 patients with rheumatoid arthritis (RA) and 16 patients with ankylosing spondylitis (AS) (22 women, 14 men, mean ages 43.3 ± 8.8 years), and 18 healthy controls (10 women, 8 men, mean ages 42.5 ± 9.9 years) matched by age and body mass index were enrolled in this study. For the evaluation of enthesal structures, all patients and controls underwent ultrasonographic (USG) examinations of five enthesal sites of both lower limbs using high-resolution and Doppler USG. An ultrasonographic score of lower limb enthesitis was calculated using Glasgow ultrasound enthesitis scoring system (GUESS). Clinical and laboratory activities of IRD patients were also evaluated. Patient group was made to undergo 2 g/day sulfasalazine monotherapy for 1 year. All evaluations were made at the beginning of the treatment and repeated after 1 year follow-up. Results showed that the frequency of enthesal abnormalities of the IRD group was significantly higher than controls. On USG examination, 301/1,296 (23.2%) enthesal structures were abnormal in IRD patients, and 19/648 (2.93%) structures were abnormal in controls. Mean GUESS score of the IRD group (6.40 ± 2.41) was also significantly higher than controls (1.79 ± 1.60) (p < 0.001). Although there was a significant improvement in clinical and laboratory activity parameters of the IRD patients, significant decrease was not observed in enthesal abnormalities (295/1,296 enthesal structures—22.7%) and mean GUESS score (6.20 ± 2.38) after 1 year sulfasalazine trial. Additionally, there was no significant improvement in enthesal abnormalities and mean GUESS scores of AS and RA subgroups separately. Sulfasalazine treatment was not found effective on enthesal abnormalities of IRD patients. Further studies with larger groups including other IRDs are required to validate our results.