Primary ankylosing spondylitis, psoriatic and enteropathic spondyloarthropathy: a controlled analysis

Within our ankylosing spondylitis (AS) population (n = 1331), 85% (n = 1128) had primary AS (1 degree AS), 9% (n = 121) had psoriatic AS (PsAS) and 6% (n = 82) enteropathic AS (IBDAS). In an attempt to explore further the relationship between 1 degree AS and the secondary spondyloarthritides, we evaluated 121 consecutive patients with PsAS and 82 with IBDAS, as well as 202 controls with primary disease. The patients were matched for sex and age at review PsAS:48.1 (SD 11.3) years vs 1 degree AS:48.4 (SD 11.5), and IBDAS:46.0 (SD 12.7) vs 1 degree AS:45.9 (SD 12.7). The sex distribution for IBDAS (M:F, 1:1), was significantly less (p less than 0.001) than that for PsAS (M:F, 3.5:1) or 1 degree AS (M:F, 2.4:1). Overall, compared to 1 degree AS the PsAS and IBDAS tended to have greater disease severity as defined by e.g., (1) those taking non-steroidal antiinflammatory drugs, 86 vs 72% (p less than 0.01) and 71 vs 60% (p less than 0.05), respectively; (2) decreased spinal mobility (scale 0-8) 5.0 (SD 2.0) vs 4.4 (SD 2.3); p = 0.029 and 4.9 (SD 2.0) vs 3.9 (SD 2.4); p = 0.024, respectively; and (3) PsAS resulted in a higher AIMS pain score; 4.9 (SD 2.5) vs 4.0 (SD 2.4): p = 0.042. By contrast, peripheral joint involvement, number of total hip replacements and capacity for employment were similar in all 3 groups. In conclusion (1) among the AS population the prevalence of 1 degree AS, PsAS and IBDAS is 90, 6 and 4%, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)