Addressing disparities in the long-term mortality of non-ST segment myocardial infarction (NSTEMI) patients according to the presence of diabetes mellitus: a nationwide cohort study

Abstract Background Diabetes mellitus (DM) is an important risk factor for non−ST segment elevation myocardial infarction (NSTEMI). How DM is related to management and longer-term clinical outcomes in contemporary NSTEMI cohorts is not well described. Methods and Results We analysed data on 456,376 adults hospitalised with NSTEMI from the United Kingdom Myocardial Ischaemia National Audit Project (MINAP) registry, linked with Office for National Statistics (ONS) death registry. We compared outcomes and quality of care by DM status. People with DM were older (median age 74 vs. 73 years, p<0.001) and more commonly of Asian ethnicity (13% vs. 4%, p< 0.001). Those with DM underwent invasive coronary angiography (59% vs. 63%, p <0.001) or revascularization (PCI or CABG) (38% vs. 40%, p <0.001) less frequently. Mortality risks for people with DM were significantly higher at 30-days (HR: 1.06, CI; 1.04-1.09, p <0.001), 1-year, (HR: 1.17, CI; 1.15-1.18, p <0.001) and 5-years, (HR: 1.25, CI; 1.24-1.26, p <0.001), when compared to people without DM. In people with DM, higher-quality inpatient care, assessed by opportunity-based quality-indicator score category (OBQI; poor, fair, good or excellent), was associated with lower mortality rates (good: HR 0.70, CI 0.67-0.73, P<0.001; excellent: HR 0.59, CI 0.57- 0.62, P<0.001), when compared to people receiving poor quality care. In people with DM, "excellent-care", compared to those receiving poor quality care, was associated with the lowest mortality in diet-treated or insulin-treated subgroups (diet-treated: HR 0.55, CI 0.50-0.61, P<0.001)(insulin-treated: 0.60 CI 0.56-0.64, P<0.001). Conclusion People with DM experience wide disparities in inpatient care following NSTEMI. They have a higher risk of long-term mortality compared to people without DM, with some evidence that better quality inpatient care is linked to better survival.