Clinical and radiological features of ankylosing spondylitis in the 1950's and in 1976 at the same hospital.

The clinical and radiological pictures of AS in two patient series were compared to ascertain whether or not the course of AS has changed since the 1950's. Clinical and radiological features were analysed from X-ray pictures and records of patients with a diagnosis of AS treated at the Rheumatism Foundation Hospital in 1952--59 (168 patients) and 1976 (160 patients). No significant difference in the clinical findings could be demonstrated between the two patient series. The radiological progression in the sacroiliacal joints and the lumbar spine was more rapid in the 1950's than in 1976. In the 1950's 82.1% of all patients had grade III or IV sacro-iliitis, whereas the figure for 1976 was 67.5%. The difference is statistically significant (p less than 0.01). Two-thirds of patients with a duration of the disease of less than 4 years had grade III or IV sacro-iliitis in the 1950's compared with only one-third in 1976. 14.6% of the patients in the 1950's and 4.8% in 1976 had more than 10 lumbar syndesmophytes. The difference is statistically significant (p less than 0.01). Possible reasons for the difference observed are discussed.