30 day survival following admission with suspected myocardial infarction by system of classification
| Classification system (No. with confirmed MI/No. in group) | Survival (%) for “confirmed MI” (No. of events) | Survival (%) for the remainder of the cohort | Unadjusted hazard ratio for “confirmed MI” v remainder (95% CI) | Adjusted hazard ratio* for “confirmed MI” v remainder (95% CI) |
|---|---|---|---|---|
| Hazard ratio and 95% confidence interval: adjusted for age, sex, past history of myocardial infarction, Killip score on admission, receiving a diuretic on discharge, abnormal ECG, or cardiac enzymes during admission. | ||||
| *p < 0.01. | ||||
| Total number of events for all ages, n=357. | ||||
| CI, confidence interval; MI, myocardial infarction; MONICA, monitoring trends and determinants in cardiovascular disease study; NHAR, Nottingham heart attack register; OXMIS, Oxford myocardial infarction study; UKHAS, United Kingdom heart attack study. | ||||
| NHAR original classification | ||||
| All: n=723/2739 | 77% (167) | 91% | 2.77* (2.24 to 3.41) | 12.0* (9.0 to 16.0) |
| Under 65 (289/991) | 87% (37) | 97% | 3.95* (2.36 to 6.61) | |
| Under 76 (547/1959) | 82% (98) | 93% | 2.87* (2.13 to 3.75) | |
| Under 80 (628/2250) | 78% (135) | 93% | 3.28* (2.56 to 4.20) | |
| NHAR amended classifications | ||||
| Extended ECG and single cardiac enzyme (1224/2739) | 85% (184) | 89% | 1.40* (1.13 to 1.72) | 3.73* (2.86 to 4.86) |
| All likely “acute coronary syndromes” (1825/2739) | 89% (199) | 83% | 0.62* (0.50 to 0.76) | 0.86 (0.77 to 1.25) |
| MONICA classification | ||||
| All: n=1051/2739 | 84% (171) | 89% | 1.57* (1.28 to 1.94) | 6.84* (5.10 to 9.20) |
| Under 65: n=404/991 | 91% (38) | 96% | 2.47* (1.48 to 4.16) | |
| Under 80: n=904/2250 (OXMIS) | 85% (135) | 91% | 1.80* (1.40 to 2.30) | |
| UKHAS classification | ||||
| All: n=807/2739 | 86% (117) | 89% | 1.20 (0.91 to 1.49) | 4.54* (3.10 to 6.64) |
| Under 76: n=621/1959 | 88% (72) | 95% | 1.27 (0.95 to 1.70) | |