Short-Term Efficacy of Hydroxychloroquine Versus Sulfasalazine in the Treatment of Undifferentiated Arthritis

Abstract

Background: Early undifferentiated arthritis (UA) is an inflammatory joint disorder lasting under three months that does not meet criteria for specific rheumatic diseases. Some cases resolve spontaneously, while others progress to rheumatoid arthritis (RA) or related conditions. Early treatment may improve prognosis, but optimal therapy is uncertain. Methotrexate (MTX) is often first-line; however, sulfasalazine and hydroxychloroquine are alternatives when contraindications exist. Concerns about combination therapy toxicity and lack of direct comparisons prompted this study. Objectives: The present study aimed to compare the clinical efficacy of sulfasalazine and hydroxychloroquine in patients with early UA. Methods: This retrospective study evaluated 70 patients presenting with pain, swelling, or limited movement in one or both knees at Shahid Sadoughi Hospital. Patients were assigned to either sulfasalazine 1000 mg/day (n = 35) or hydroxychloroquine 400 mg/day (n = 35) for 12 weeks. Outcomes included pain scores, knee swelling, and range of joint motion. Complete clinical response rates were also assessed. Results: The groups were similar in age and gender (P > 0.05). Baseline pain scores were 6.08 ± 1.14 (hydroxychloroquine) and 6.80 ± 1.30 (sulfasalazine). After treatment, pain decreased to 3.02 ± 1.97 and 1.77 ± 1.91, respectively (P < 0.05 for both), with greater reduction in the sulfasalazine group. No significant between-group differences were found in swelling or range of motion (P > 0.05). Complete clinical response occurred in 14.2% (hydroxychloroquine) versus 37.1% (sulfasalazine) (P < 0.05). Conclusions: Both treatments significantly reduced pain in early UA, but sulfasalazine provided greater pain relief and higher rates of complete clinical response, suggesting it may be more effective for this patient population in the short-term.