Abstract 3212: Does Less Use Of Secondary Prevention Medication In Patients With Non-st Elevation Myocardial Infarction Explain Their Higher 1-year Mortality Than St Elevation Myocardial Infarction? - The Myocardial Infarction National Audit Project
Background: Non-ST elevation myocardial infarction (NSTEMI) is now more common than STEMI, but is often treated less aggressively with uncertain effects on long-term prognosis.
Methods: The Myocardial Infarction National Audit Project registry records data for all AMIs admitted to hospital in England and Wales and provides a unique opportunity to resolve this uncertainty.
Results: There were 63,740 NSTEMI (55%) and 51,413 STEMI patients admitted in 2004 –2005. Patients with NSTEMI were older (72±13 vs 66±13 years), a greater proportion were women (38% vs 31%), and more had had previous AMI (26% vs 14%). Although >75% received aspirin and low molecular weight heparin, other evidence-based emergency strategies were applied less frequently and the odds relative to STEMI of receiving 2° prevention were 0.84 (95%CI 0.80 – 0.89) for aspirin, 0.69 (0.66 – 0.72) for beta-blockers, 0.67 (0.64 – 0.71) for statins, and 0.58 (0.56 – 0.61) for ACE-I. Myocardial injury assessed by peak CK (281, IQR 124 – 682) IU/L vs 856 (290 –1833) IU/L) and troponin (0.14, 0.04 – 0.55) μmol/L vs 0. 56 (0.15–2.39) μmol/L) was less severe in NSTEMI than STEMI, but the probability of death was greater at 1 year after hospital discharge (Figure⇓). After adjustment for age, the HR was 1.46 (95%CI 1.38 –1.55) in men and 1.34 (1.25–1.48) in women; and after additional adjustment for each of the 4 classes of secondary prevention drugs, it was 1.36 (1.28 –1.44) and 1.26 (1.18 –1.35) respectively.
Conclusion: Despite less severe myocardial injury, 1 year mortality is greater for NSTEMI than STEMI. Secondary prevention medication was underused among NSTEMI patients, but this only partly explained the higher mortality.