A COMPARISON OF PATIENTS WITH SPONDYLOARTHROPATHY SEEN IN SPECIALTY CLINICS WITH THOSE IDENTIFIED IN A COMMUNITY-WIDE EPIDEMIOLOGIC-STUDY -HAS THE CLASSIC CASE MISLED US

Background: Undiagnosed cases of seronegative spondyloarthropathy (Spa ) are often observed during epidemiologic studies. Objective: To deter mine the extent of and the reasons for the underdiagnosis of Spa. Meth ods: We studied 2 groups of Alaskan native patients with Spa using a s tandardized protocol that included an interview, physical examination, medical record review, and radiographic and laboratory examinations, One group consisted of patients identified in a communitywide epidemio logic study; the other group consisted of patients from related but ge ographically separate populations who had been diagnosed by a speciali st in the hospital or a specialty clinic. All cases met the current cl assification criteria for Spa. The clinical and demographic features o f the cases in the 2 groups were compared. Results: Fifty-five (72%) o f the 76 community cases that we identified in the epidemiologic study had not been diagnosed previously as Spa. Among the undiagnosed pa ti ents were 34 (94%) of the 36 women, 11 (65%) of the 17 patients with a nkylosing spondylitis, 12 (36%) of the 33 patients with reactive arthr itis, and 24 (100%) of those with undifferentiated Spa. The community and specialty clinic patient groups were similar in age of onset of jo int and back pain and in overall symptoms. The specialty clinic group had a higher proportion of men, more severe disease, and a higher freq uency of iritis. Conclusions: The diagnosis of Spa was missed more oft en than not in the primary care setting, probably because most of the cases were of mild or moderate severity and did not fit the classic de scriptions of spondyloarthropathic disorders. The higher proportion of men among the specialty clinic cases probably reflects provider expec tation as well as a slightly milder disease course in women.