Mortality and causes of death in 398 patients admitted to hospital with ankylosing spondylitis.

The mortality and causes of death in 398 patients (47 women, 351 men) with definite ankylosing spondylitis, admitted to hospital for the first time between 1961 and 1969, were investigated. The mean age at first admission was 36.5 years (SD 11.8). After a mean follow up time of 25.7 years, a total of 152 patients (12 women, 140 men) had died. The expected mortality based on the mortality statistics of the general population of the same sex and age was 103.1 (9.4 women and 93.7 men). Thus the overall mortality of the patients with ankylosing spondylitis was 1.5 times that expected. Those patients who had died were significantly older, had a higher erythrocyte sedimentation rate, and more inflamed peripheral joints when first seen than the surviving patients. The main difference between the observed and expected causes of death was the high incidence of deaths from ankylosing spondylitis, which was the underlying cause of death in 27 patients. The mechanism of death in these patients was secondary amyloidosis in 19, cardiovascular complications in six, fracture of the spine in one, and it was not known in one patient. Excess deaths due to circulatory, gastrointestinal and renal diseases, and violence were also observed.