THU0427 SHOULD FEBUXOSTAT-RESISTANCE BE ADDED TO CRITERIA FOR REFRACTORY GOUT? A PRELIMINARY STUDY
Authors: Z. Huang, W. Zhao, D. Deng, Y. Liu, S. Chen, J. Chen, T. LI
Journal: Annals of the Rheumatic Diseases (2020)

Background: Refractory gout manifests as recurrent flares, chronic arthritis and progressive tophaceous deposits. Febuxostat is a widely-used potent serum urate-lowering reagent, but some gout patients cannot achieve target serum uric acid (sUA) after they used this reagent. Objectives: To determine whether febuxostat-resistance should be a criterion for refractory gout, characteristics of gout patients who were resistance to febuxostat or allopurinol were compared. Methods: This study was performed from December 2015 to December 2019. Medical records of gout patients who met the 2015 gout classification criteria [1] and undertook febuxostat (febuxostat group) or allopurinol (allopurinol group) urate-lowing therapy (ULT) were assessed. Dose of ULT was adjusted till sUA was below 6 mg/dL and 5 mg/dL for patients with urate deposition. We screened gout patients who had contraindication or history of failure to normalize sUA for≥ 3 months of treatment with the maximum medically appropriate febuxostat (febuxostat-resistance) or allopurinol (allopurinol-resistance) dose as defined by physicians. Furthermore, these screened patients met the traditional criteria of refractory gout except therapeutic reaction [2].Demography and clinical characteristics were recorded. Features between febuxostat-resistance and allopurinol-resistance patients were compared. Results: (1) Of 683 gout patients who were included, 516 and 167 of them used febuxostat or allopurinol. (2) Age (41.92±11.58 vs. 42.26±9.41 years), Male gender (97.50% vs. 97.01%), duration of gout (5.78±4.74 vs. 5.05±4.72 years) and sUA (6.30±2.50 vs. 6.67±2.14 mg/dL) were similar between febuxostat group and allopurinol group ( P &gt;0.05). (3) Dose of febuxostat or allopurinol were 47.28mg/day and 178.24mg/day. (4) Sixteen patients were febuxostat-resistance, while 6 patients were allopurinol-resistance. Prevalence rates of treatment resistance were comparable between groups (3.10% vs. 3.59%, P &gt;0.05). (5) Some parameters were different between resistance patients and non-resistance patients in both groups (Table 1, P &lt;0.05). However, characteristics of febuxostat-resistance and allopurinol-resistance patients were similar ( P &gt;0.05). Table 1 Characteristics of gout patients in febuxostat group and allopurinol group Parameters Febuxostat Group Allopurinol Group Non-resistance (n=500) Resistance (n=16) Non-resistance (n=161) Resistance (n=6) Age (year) 41.93±11.65 41.67±9.58 42.22±13.33 44.50±16.98 Male Gender (%) 97.40 100.00 96.89 100.00 BMI (kg/m 2 ) 25.44±3.46 26.22±3.47 25.86±3.97 25.60±6.42 Duration of gout (years) 5.75±4.76 7.00±3.97 * 4.96±4.73 7.75±2.62 * Flares in previous 18 months (times) 1.31±0.44 3.67±0.70 * 1.13±0.24 3.25±0.50 * Presence of Tophi (%) 23.80 100.00 * 14.90 100.00 * Presence of Complication (%) 35.8 100.00 * 31.06 100.00 * sUA (mg/dL) 6.21±2.47 9.13±1.24 * 6.42±2.32 10.15±3.55 * SCr (μmol/L) 100.67±15.03 163.96±29.41 * 96.93±22.91 133.75±31.60 * ESR (mm/L) 24.59±19.28 42.83±21.13 * 27.49±24.10 56.50±28.12 * CRP (mg/L) 18.92±18.59 28.81±23.85 * 23.12±22.63 32.28±23.64 * * P &lt;0.05 compared with non-resistance patients in the same group. BMI body mass index, sUA serum uric acid, SCr serum creatinine, ESR erythrocyte sedimentation rate, CRP C-reactive protein Conclusion: Febuxostat-resistance is a potential criterion for refractory gout, because febuxostat-resistance patients shares similar characteristics of patients with refractory gout. References: [1]Neogi T, Jansen TL, Dalbeth N, et al. 2015 Gout classification criteria: an American College of Rheumatology/European League Against Rheumatism collaborative initiative. Ann Rheum Dis 2015;74(10):1789-1798. [2]Lawrence Edwards N, Singh JA, Troum O, et al. Characterization of patients with chronic refractory gout who do and do not have clinically apparent tophi and their response to pegloticase. Rheumatology (Oxford) 2019; pii: kez017. Acknowledgments: None. Disclosure of Interests: : None declared