A double-blind, randomized controlled clinical study of Kidney Supplementation Formula in the treatment of patients with Ankylosing Spondylitis Experiencing Disease Recurrence during Biologic Dose Reduction

INTERVENTION: Intervention Group:Oral Kidney Supplementation Formula, consisting of Gouji, Shudihuang, Gusuibu, Fuzi, Lujiaoshuang, etc., one dose daily, taken in the morning and evening, for 12 weeks. The intervention group will also continue the original biologic dose reduction regimen and may use non‐steroidal anti‐inflammatory drugs as needed.;Control Group:Oral Chinese herbal placebo, consisting of caramel color 0.0018, bittering agent 0.00003, xanthan gum 0.003, and Chinese herbal liquid up to a maximum of 10%, one dose daily, taken in the morning and evening, for 12 weeks. Participants in the control group will continue the original biologic dose‐reduction regimen and may use non‐steroidal anti‐inflammatory drugs as needed. Prepared by the Pharmacy Department of China‐Japan Friendship Hospital.; CONDITION: Ankylosing Spondylitis PRIMARY OUTCOME: ASAS20 response rate at week 12; SECONDARY OUTCOME: ASAS40 response rate at week 12;ASDAS‐CRP at Week 12;Symptoms and Signs;TCM Syndrome Score;Disease Activity;Quality of Life Change;NSAIDs Intake Scoring;The first time achieving ASAS20 response.; INCLUSION CRITERIA: 1. Age 18‐75 years; 2. Diagnosed with AS according to the 1984 revised New York criteria of the American Rheumatism Association or the 2009 axial spondyloarthritis classification criteria of the Assessment of Spondyloarthritis International Society (ASAS); 3. Patients who have received biologic therapy and experienced disease recurrence during the tapering phase of biologic treatment; 4. Meet the criteria for active AS: ASDAS‐CRP = 2.1; (ASAS‐CRP calculation formula: 0.12 × spinal pain + 0.06 × morning stiffness duration + 0.11 × patient assessment + 0.07 × peripheral joint swelling and pain score + 0.58 × Ln(CRP + 1)). 5. TCM syndrome differentiation is "Kidney Deficiency andCold Syndrome," referring to the "Treatments for(Ankylosing Spondylitis) in Traditional Chinese Medicine" issued by the National Administration of Traditional Chinese Medicine (2017 edition) and the "Collaborative Diagnosis and Treatment Plan for(Ankylosing Spondylitis) of the R