To examine the efficacy of available drugs in undifferentiated spondyloarthritis (u-SpA).
Systematic review of studies retrieved from Medline (1961-July 2009), Embase (1961-July 2009), and Cochrane Library (up to July 2009). A complementary hand search was also performed. The selection criteria were as follows: (population) u-SpA patients; (intervention) nonsteroidal anti-inflammatory agents, disease-modifying antirheumatic drugs, anti-tumor necrosis factor α, anakinra, abatacept, biphosphonates, or thalidomide; (outcome) pain, function, structural damage and quality of life; (study design) randomized controlled trials (RCT), cohort studies, and case reports; (level of evidence) according to The Oxford Centre for Evidence-based Medicine (update 2009). An additional narrative review was performed to analyze the effects of drug therapies in patients with spondyloarthritis according new Assessment of Spondyloarthritis International Society criteria.
The following 7 studies were included: 2 RCT, 1 cohort study, and 4 case reports, which included 117 patients with u-SpA (mostly young men). No evidence related to the effect of nonsteroidal anti-inflammatory agents or disease-modifying antirheumatic drugs on u-SpA patients was found. Infliximab and etanercept showed some benefit regarding clinical outcomes, function, and quality of life. Two RCT reported important benefit of infliximab and adalimumab also in patients with predominantly axial spondyloarthritis. Rifampicin plus doxycycline improved some clinical outcomes but ciprofloxacin had no benefit. Anecdotal positive evidence was reported with pamidronate. No serious adverse events were reported in the retrieved studies.
Low-quality evidence suggests a benefit of tumor necrosis factor α blockers in u-SpA and good-quality evidence in predominantly axial spondyloarthritis. The use of antibiotics remains controversial. High-quality trials are needed to definitively assess the effect of available drugs in these patients.