Relapse of Ankylosing Spondylitis Patients Withdrawal Etanercept After Clinical Remission: a Following-up Study

The inclusion criteria was patients who aged 18 or older with ankylosing spondylitis, fulfilled the 1984 modified New York criteria for AS. Inclusion criteria enriched the AS patients with clinical remission, including the following definition: 1. Administration of etanercept 50 mg for 6-week period at least; 2. Acquisition of Assessment of SpondyloArthritis International Society criteria 20(ASAS20) response at the end of the treatment. We excluded patients who have developed to complete spinal fusion. We also excluded patients with kidney disease induced by other conditions; pregnancy; suckle; accompany other chronic diseases; various infections in acute stage; and other infectious diseases. At the end of the trial, patients who fulfilled the inclusions would stop etanercept treatment. Cotherapy with disease modifying anti-rheumatic drugs or non-steroidal anti-inflammatory drugs could be continued if maintained at a stable dose;Patients were followed up from the time of etanercept withdrawal per 6 weeks for 3 years by telephone. If symptoms suggestive of relapse or other problems occurred, patients were invited to come back to the center. Relapse after etanercept withdrawal was defined as an increase Bath Spondylitis Disease Activity Index(BASDAI)15 score goes back to 80 percentages of it at the beginning of the trial16. The following data were collected: demographic and disease characteristics, therapeutic modification, clinical values (BASFI, Bath Ankylosing Spondylitis Global Score (BAS-G)), Ankylosing Spondylitis Disease Activity Score (ASDAS)1718) and biologic values at baseline of the trial and the time of relapse. Adverse events and other safety measures were also collected.