Hospital discharge rates for suspected acute coronary syndromes between 1990 and 2000: population based analysis.

We got data from the Scottish morbidity record for Scottish residents aged at least 18 years with a “first” emergency hospitalisation for myocardial infarction (codes ICD-9 (international classification of diseases, ninth revision) 410, ICD-10 I21 or I22), angina (ICD-9 411 or 413; ICD-10 I20 or I24.9) or “other chest pain” (ICD-9 786.5; ICD-10 R07), between 1990 and 2000. We analysed discharges coded only in the principal position. A “first” hospitalisation was one with no discharge diagnosis of coronary heart disease or chest pain in the previous 10 years. We calculated rates using annual official age and sex specific population estimates for 1990-2000 and tested the significance of trends in discharge rates with linear regression. We found 225 512 first hospitalisations for suspected acute coronary syndrome with a discharge diagnosis of myocardial infarction in 96 026 (43%), angina in 37 403 (17%), and other chest pain in 92 083 (41%). Patients with angina were on average 11 years older and those with myocardial infarction 13 years older than patients with chest pain (both P < 0.001). The population discharge rate for myocardial infarction fell by a third, from 260 to 173 per 100 000 between 1990 and 2000 (regression coefficient (average change per year in population hospitalisation rate) − 9.9; 95% confidence interval − 11.5 to − 8.2). Conversely, the rate for angina increased by 79%, from 59 to 105 per 100 000 (5.2; 4.3 to 6.1). The discharge rate for other chest pain increased by 110%, from 114 to 296 per 100 000 (coefficient 13.6; 11.6 to 15.5). The rate for myocardial infarction or angina decreased by 12%, from 319 to 278 per 100 000 ( − 4.7; − 6.6 to − 2.7), though that for any suspected acute coronary syndrome increased by a quarter, from 460 to 574 per 100 000 (8.9; 6.0 to 11.8). The greatest change, across all diagnostic subgroups, was in elderly people (figure). The decline in myocardial infarction was much greater in men than in women in young and older age groups. The increase in angina was slightly greater in men than in women in both age groups. For chest pain, the increases were comparable in men and women in both age groups.