Evaluation of the short-term efficacy of NSAIDs on patients with active ankylosing spondylitis in daily practice: a 3-month, longitudinal, observational study.

The objective of the study was to investigate the response rate to non-steroidal anti-inflammatory drugs (NSAIDs) and the clinical parameters that might predict this response in patients with active ankylosing spondylitis. This is a prospective, observational, 3-month study that was conducted in a single center. Ninety-five consecutive patients with active ankylosing spondylitis were included in the study. Full dose NSAIDs (indometacin 150 mg daily or acemetacin [corrected] 180 mg daily) were given to patients. Relevant clinical data of all patients' were recorded at the beginning and on three consecutive monthly visits. At the end of the study period, patients who respond to NSAIDs were determined. Demographic, clinical, and laboratory parameters that might influence the response to the NSAIDs were investigated. The response rate to the full-dose NSAIDs according to the ASAS20 in patients with active ankylosing spondylitis was found as 29.5%. Similarly, 20.0% of the patients were responders according to the ASAS40 criteria, whereas 5.6% of the patients responded according to the 5-out-of-6 criteria at week 12. Patients who responded to the treatment were found to be younger at the study entry (P = 0.001) and had shorter disease duration (P < 0.001). Due to the markedly lower rate of response to the NSAIDs in patients with active ankylosing spondylitis, early identification of those patients who does not respond to NSAIDs and subsequent decision regarding the institution of second-line treatments (anti-TNF) may be of great value in the prevention of irreversible changes that might develop in most of the patients.