Diabetes mellitus, frailty and prognosis in very elderly patients with acute coronary syndromes

Background The magnitude of the association between diabetes (DM) and outcomes in elderly patients with acute coronary syndromes (ACS) is controversial. No study assessed the prognostic impact of DM according to frailty status in these patients. Methods The LONGEVO-SCA registry included unselected ACS patients aged ≥ 80 years. Frailty was assessed by the FRAIL scale. We evaluated the impact of previous known DM on the incidence of death or readmission at 6 months according to status frailty by the Cox regression method. Results A total of 532 patients were included. Mean age was 84.3 years, and 212 patients (39.8%) had previous DM diagnosis. Patients with DM had more comorbidities and higher prevalence of frailty (33% vs 21.9%, p = 0.002). The incidence of death or readmission at 6 months was higher in patients with DM (HR 1.52, 95% CI 1.12–2.05, p 0.007), but after adjusting for potential confounders this association was not significant. The association between DM and outcomes was not significant in robust patients, but it was especially significant in patients with frailty [HR 1.72 (1.05–2.81), p = 0.030, p value for interaction = 0.049]. Conclusions About 40% of elderly patients with ACS had previous known DM diagnosis. The association between DM and outcomes was different according to frailty status.