Roentgenological features of ankylosing spondylitis. A comparison between patients attending hospital and cases selected through an epidemiological survey.

A roentgenological comparison between 105 hospital cases (HOSP AS) of ankylosing spondylitis and 27 cases selected through an epidemiological survey (EPI AS) was performed. The male HOSP AS patients exhibited more severe X-ray changes in the sacroiliac joints as compared to male EPI AS patients. The female HOSP AS patients more frequently exhibited lumbar X-ray changes typical of AS when compared to the female EPI AS patients. The main impression from the findings were that more severe and extensive radiological features were present in the AS cases selected through the Department of Rheumatology than in the cases present in the general population.