Recurrence of acute coronary syndrome in the elderly: predictors and prognosis insights from a multicentre national registry

Abstract The burden of cardiovascular (CV) disease remains at the top of society's health problems, with acute coronary syndromes (ACS) undoubtedly being one of the major causes. Patients with a known history of CVD are at increased risk of recurrent events. However, this recurrence's incidence rate and clinical impact vary between populations. Elderly patients represent a large proportion of patients admitted for a second ACS. The decision on its management lacks support in clinical guidelines, as studies generally exclude patients with significant comorbidities and tend to underrepresent this group. This study aimed to analyse the characteristics and outcomes of elderly patients admitted with ACS with a previous history of myocardial infarction (MI) versus those who did not. The authors performed a retrospective analysis of patients older than 75 years included in the Portuguese Registry on Acute Coronary Syndromes (ProACS) between 2010 and 2022. Comparison tests were performed. A COX proportional hazard regression method was applied to generate the proposed risk models. A p-value less than 0.05 was considered statistically significant. A total of 8658 patients older than 75 years admitted for ACS were analysed, 6630 (76.6%) without a history of MI (group 1) and 2028 (23.4%) with a previous MI. Table 1 shows the most important baseline characteristics and differences between groups. Table 2 demonstrates the group differences regarding admission diagnosis, complementary study results and treatment. Table 3 represents in-hospital complications. At discharge, 16.5% of group 1 and 21.2% of group 2 had a planned cardiac rehabilitation program (CRP) (p-value=0.01). At 1-year follow-up, 15,6% of patients with more than 75 years admitted for ACS died and 17.4% were re-hospitalized by a CV cause. COX-regression analysis identified the history of MI as a predictor factor of CV re-hospitalization (HR 1,43; 95%CI [1.10;1.86], p-value<0.01) and of the composite of mortality and CV re-hospitalization (HR 1,37; 95%CI [1.10;1.71], p-value<0.01). In conclusion, the elderly with a second episode of ACS tends to have more CV risk factors and comorbidities than those without a MI history. Furthermore, the recurrence of MI seems to be an independent predictor of 1-year re-hospitalization and the composite of mortality and CV re-hospitalization. Then, these results should increase the awareness of this group of patients.Table 1Table 2 (incomplete) and Table 3