Long-term efficacy of iguratimod in treating knee osteoarthritis: a 12-month retrospective study

To evaluate the long-term efficacy and safety of iguratimod (IGU) in patients with knee osteoarthritis (KOA).

This retrospective study included patients diagnosed with KOA at Beijing Jishuitan Hospital between July 2023 and January 2024. All participants received IGU monotherapy at a dose of 25 mg twice daily for 3 months and were subsequently followed for a total duration of 12 months. Clinical data, including demographic characteristics, laboratory tests, and imaging assessments, were systematically collected and analyzed. Pain intensity, global disease assessment, physical function, and adverse events were evaluated at baseline, 3 months, and 12 months.

A total of 62 patients were included in the analysis, of whom 77.4% were female. The mean age was 58.56 ± 8.57 years, and disease duration ranged from less than 1 year to more than 10 years. At baseline, the mean Visual Analogue Scale (VAS) score was 6.08 ± 1.56, and the mean Patient Global Assessment (PGA) score was 3.94 ± 1.34. Significant reductions in both scores were observed at 3 and 12 months. The VAS score decreased to 2.39 ± 1.64 at 3 months and 2.65 ± 1.70 at 12 months, while the PGA score declined to 1.39 ± 1.07 and 1.53 ± 1.21, respectively (all p < 0.001). The median total functional score improved markedly from 6.00 (IQR: 5.00) at baseline to 1.00 (IQR: 3.00) at 3 months and 1.00 (IQR: 2.00) at 12 months (p < 0.001). At 3 months, 51.6% of patients achieved a squat test score of 0, and 66.1% achieved a stair climbing test score of 1; these functional gains were maintained at 12 months (p < 0.001). Similar improvements were observed across additional functional domains. At both follow-up time points, 58.1% of patients reported no restriction in the chair rise test, 98.4% reported no joint stiffness, and 91.9% reported no limitation in walking distance (p < 0.001 for all comparisons). The incidence of adverse events associated with IGU monotherapy was 0.03%, and the treatment was generally well tolerated.

IGU demonstrated sustained efficacy and a favorable safety profile in patients with KOA. Significant improvements in pain and physical function were observed after 3 months of treatment and were maintained for at least 12 months. These findings support the potential role of IGU as a long-term therapeutic option for KOA. Key Points •This study supports the potential of iguratimod as an effective long-term treatment option for patients with non-inflammatory phenotypes of KOA. •Significant and sustained improvements were observed in VAS, PGA, and physical functional scores from baseline to 3 and 12 months.