Background: Patients with diabetes and a history of acute coronary syndrome (ACS) are at high risk for further cardiovascular events and death, but management of ACS risk and events is improving.
Aim: To determine whether 5-year survival has increased in patients with type 2 diabetes after hospitalisation for ACS.
Patients and Methods: Type 2 patients recruited to the community-based Fremantle Diabetes Study Phase I (1993-6) and hospitalised with a myocardial infarction (MI)/unstable angina (UA) two years prior to recruitment or later as verified through validated data linkage to end-December 2012 were eligible.
Results: 438 of 1296 patients (33.8%) had a first hospitalisation for/with MI/UA between 2.0 years before and 19.4 years after entry (mean±SD 5.5±5.6 years) between 1991 and 2012. At hospitalisation, these participants were aged 70.5±10.7 years, 50.5% were male and their diabetes duration was a median [interquartile range] of 11.9 [5.6-19.9] years. The 160 (36.5%) who died within the next 5 years were older at hospitalisation (75.2±9.9 vs 67.2±10.0 years, P<0.001) and diabetes diagnosis (59.2±13.8 vs 55.2±12.0 years, P=0.002), and had longer median diabetes duration (14.4 [7.1-23.7] vs 10.4 [4.7-17.8] years, P<0.001) than the 278 who did not. There were ≥5 years of follow-up in 376 (85.8%) who had their first ACS event during four 4-year periods between 1992 and 2007. In Kaplan-Meier analysis using age as the timeline from first ACS event, there was no difference in 5-year survival between time periods (P=0.38). Using Cox proportional hazards modelling and after further adjustment for sex, Aboriginality and diabetes duration, those hospitalised after 1999 were >40% less likely to die within 5 years compared with those hospitalised during 1992-1995 (hazard ratio (95% CI): 0.56 (0.33-0.95) for 2000-2003 and 0.57 (0.34-0.96) for 2004-2007).
Conclusions: Post-ACS survival is improving in Australians with type 2 diabetes. Although this could reflect survivor bias, improved inpatient ACS management and more intensive cardiovascular risk factor modification are likely to have played a significant role.