Introduction:
Despite substantial improvements in treatment, adherence to guideline indicated treatment for acute myocardial infarction (AMI) patients remains sub-optimal. Therefore, the purpose of this research project was to investigate the quality of care and associated outcomes of patients hospitalised with AMI using electronic health record data.
Methods:
This thesis was based on prospective cohort data from the nationwide population-based clinical registry: Myocardial Ischaemia National Audit Project (MINAP) (2003-13). MINAP records all AMI admissions from 247 hospitals in England and Wales. The research conducted in this thesis consisted of four research strands all in the framework of assessing quality of care and outcomes for AMI patients which included: 1) determining the excess mortality associated with sub-optimal management of AMI (restricted to Non-ST-elevation myocardial infarction phenotype (NSTEMI)), 2) assessing variation in receipt of NSTEMI care, 3) investigating the association of temporal changes in clinical factors and therapeutic strategies with improvements in survival following ST-elevation myocardial infarction (STEMI) and 4) determining the efficacy of β blockers in treating AMI patients without heart failure or left ventricular systolic dysfunction (LVSD).
Results:
The majority (86.9% (n=337,881)) of the NSTEMI patients evaluated did not receive one or more guideline-indicated care interventions for which they were eligible and the identified sub-optimal care was found to be associated with 32,765 potentially avoidable deaths (95% CI 30,531 to 33,509). Most of the excess variation (99.6%) in receipt of care was due to between hospital differences (median 64.7%, IQR 57.4% to 70.0%; between hospital variance: 1.92, 95% CI 1.51 to 2.44; ICC 0.996, 0.976 to 0.999). For the STEMI phenotype the temporal improvements in six months and one year survival that have been noted between 2004 and 2013 were associated with the introduction of reperfusion (PPCI) and temporal improvements in P2Y12 inhibitors prescription at hospital discharge. No significant differences in average time to death were found if all the AMI patients without heart failure or LVSD in the population had received β blockers compared with if no patients had received β blockers.
Conclusion:
The thesis provides evidence of important care deficits in an otherwise modern and efficient national health care system. The deficits in receipt care identified were found to be associated with avoidable deaths and most of the variation in receipt of care was explained by hospital differences in provision of care. The thesis also provides evidence that the introduction of PPCI and increased prescription of P2Y12 inhibitors at discharge was associated with improved survival improvements that have been noted for STEMI patients admitted between 2004 and 2013. However, among survivors of hospitalisation with AMI without heart failure or LVSD as recorded in hospital, the use of β blockers was not associated with a lower risk of death at up to one year. Only through higher resolution investigations using whole healthcare system clinical registries can modifiable deficits of care be identified and, therefore, addressed.