The goal of this observational study is to evaluate the effectiveness and safety of acemetacin in adults (18-65 years) with active axial spondyloarthritis (axSpA) who meet the 2025 ASAS-SPARTAN revised classification criteria and have an ASDAS score greater than 2.1.
The main questions this study aims to answer are:
* Does acemetacin reduce overall pain assessed by visual analog scale (VAS) after 4 weeks of treatment? * What proportion of patients achieve clinical remission (ASDAS ≤1.3) or low disease activity (1.3\<ASDAS≤2.1) at week 4? * What medical problems (side effects) occur during acemetacin treatment, with particular attention to gastrointestinal and cardiovascular events?
Participants will:
* Undergo screening assessments including blood tests, imaging of the sacroiliac joints (MRI, CT, X-ray), and physical examination within 7 days before starting treatment * Take acemetacin 90 mg by mouth once daily for 4 weeks * Complete a phone follow-up at week 2 and an in-clinic visit at week 4 * Have pain scores, disease activity measures (ASDAS, BASDAI, BASFI, ASAS HI, BASMI), and laboratory tests (CRP, ESR) recorded at each visit * Be monitored for adverse events throughout the treatment period
Subjects who fully understand the purpose and procedures of the trial and voluntarily sign the Informed Consent Form (ICF);
Subjects aged 18-65 years (inclusive), regardless of gender;
Meet the 2025 ASAS-SPARTAN Revised Classification Criteria for Axial Spondyloarthritis;
ASDAS score > 2.1.
Subjects with known allergy to acemetacin, other NSAIDs, or any excipients;
Subjects with active gastrointestinal ulcer/bleeding, or a history of recurrent ulcer/bleeding;
Subjects with severe cardiac or renal dysfunction, or hepatic dysfunction;
Subjects with ulcerative colitis or Crohn's disease;