The SpA are a group of diseases which includes AS, reactive arthritis, arthritis/spondylitis with inflammatory bowel disease or psoriasis, and undifferentiated spondyloarthritis (Ann Intern Med. 2002;136:896–907). As a group, the SpA are one of the most common rheumatic diseases with a prevalence in the general population of 0.5–1.9% (Rheum Dis. 2004;63:535–543).

Dr. John Davis, University of California, San Francisco, CA, introduced the term “axial SpA”, which he believes perfectly describes the disease continuum consisting of the early phase of spondylitic disease without radiographic sacroiliitis (or axial undifferentiated SpA (uSpA) and the relatively later phase AS).

Common features of these diseases include: enthesopathy, absence of radiographic sacroiliitis, and positive family history. Clinical features include: achilles tendonitis, plantar fasciitis, dactylitis, mononuclear cell infiltration including T-cells & macrophages, increase in inflammatory cytokines including IL-1, IL-6, TNF-α, subchondral bone inflammation and resorption, and periosteal new bone formation.

Dr. Martin Rudwaleit, Charite'- Campus Benjamin Franklin, Berlin, Germany, provided guidelines for use of several of the assessment techniques for SpA. The Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) is the standard instrument used to measure disease activity, while the Bath Ankylosing Spondylitis Functional Index (BASFI) is used to measure physical function. Both are validated patient-reported instruments and Dr. Rudwaleit believes they are appropriate for daily clinical practice, unlike the ASessment in Ankylosing Spondylitis (ASAS) response criteria, which were designed to assess treatment response in clinical trials and are not appropriate for use in individual patient care.

According to Dr. Herman Mielants, University Hospital Gent, Belgium, effective treatment strategies for SpA must go beyond the axial skeleton, joint, and enthesis. It must also have a beneficial effect on the extra-articular targets of the disease, including the skin, eye, gut and urogenital system. He reviewed several treatments.

With an average 60% response rate, NSAIDs are the cornerstone in the treatment of SpA. However, their effect on extra-articular targets is weak and they have been associated with GI side effects. Although COX-2 selective NSAIDs (coxibs) can minimize the stomach ulcers that are associated with traditional NSAIDs, they have no effect on extra-articular manifestations and have potential side effects of their own (eg, stomach upset, diarrhea, abdominal cramps, and headaches). Corticosteroids can act favorably on gut inflammation and locally on the eye, skin and joints but have no effect on axial inflammation. DMARDs (sulfasalazine, methotrexate, leflunomide) have been proven effective for arthritis, tendonitis, and skin involvement, but they have no effect on axial disease or disease progression and generally require regular blood tests to monitor side effects.

Three biologics (infliximab [Arthritis Rheum. 2005; 52:582–91], etanercept [Arthritis Rheum. 2003; 48: 3230–3236], adalimumab [Arthritis Rheum. 2006; 54:2136–2146]) have been approved for the treatment of SpA and all show impressive effects on locomotor and extra-articular manifestations, metrology, and quality of life. Only infliximab and adalimumab produce improvement of gut inflammation in irritable bowel disease. Infliximab significantly reduces the frequency of flares of uveitis (etanercept's effect is less positive and adalimumab's is still unknown). Recent studies show that infliximab also delays structural radiological progression compared with NSAIDs; this has not yet been demonstrated for etanercept or adalimmumab. All are associated with an increased risk of infections (e.g., tuberculosis and opportunistic infections).

The increasing interest in the spondyloarthritides, the availability of validated assessment tools, and the clinical studies being conducted in this population, hold promise for strides in early diagnosis and treatment.

For more information about the BASFI, please visit: http://www.spondylitis.org/physician_resources/assesment.aspx