Abdominal aortic aneurysm: a 12-year experience in the Grampian region, Scotland.

All the 638 new hospital cases of abdominal aortic aneurysm (AAA) diagnosed in the Grampian region of Scotland, over the 12-year period between January 1980 and December 1991, were studied. Information was obtained from the Scottish Morbidity Record Form 1 (SMR1). The number of AAA cases has risen from 19 in 1980 to 84 in 1991 totalling 638 cases in the 12-year study period. Of these, 29% were women, a percentage which remained fairly constant for each year of the study. The mean age of the study population was 73.8 years; higher in women (74.7 in intact and 76.6 in ruptured cases) than in men (71 in intact and 73.1 in ruptured cases). There was a significant increase in the percentage of patients over the age of 75 years (from 31.6% in 1980 to 41.7% in 1991) which was very marked in men (from 25% to 40%). This may indicate that ageing of the population is partly responsible for the apparent increased incidence of the disease. Ruptured AAA constituted 36.5% of all cases of which 76.4% were men. The rate of ruptured cases has dropped from 73.7% in 1980 to 32.1% in 1991 probably owing to operating on more elective cases. Analysis of hospital fatality, including unoperated cases, showed a fatality rate of 8.4% for intact cases as opposed to 46.3% for ruptured cases. Allowing for improved diagnostic techniques and clinical awareness of the disease, the figures suggest a true increase in the incidence of AAA in the Grampian region.