Five-Year Outcomes after Acute Myocardial Infarction in Patients with and without Diabetes Mellitus in Taiwan, 1996-2005.

BACKGROUND Diabetes mellitus (DM) is a strong risk factor of cardiovascular disease. To date, the impact of DM on outcomes after acute myocardial infarction (AMI) in Taiwan is undetermined. The aim of this study was to compare five-year outcomes after AMI in patients with and without diabetes in Taiwan. METHODS A nationwide cohort of 25,028 diabetic and 56,028 non-diabetic patients who were first hospitalized with AMI between 1996 and 2005 was enrolled through linkage with the Taiwan National Health Insurance research database. Patient mortality rates within 30 days after AMI, and 1, 3, and 5 years thereafter were compared. RESULTS Length of hospital stay (8.9 ± 8.7 vs. 8.2 ± 8.0 days, p < 0.01) and medical cost during admission (in Taiwan dollars: $129,123 ± $158,073 vs. $121,631 ± $157,018, p < 0.01) were significantly higher in diabetic patients. The difference in mortality rate within 30 days was insignificant between diabetic and non-diabetic patients (18.1% vs. 17.6%, p = 0.06). Mortalities within 1 year (31.0% vs. 26.8%, p < 0.01), 3 years (42.4% vs. 34.7%, p < 0.01), and 5 years (50.6% vs. 41.1%, p < 0.01) were significantly higher in diabetic patients. In patients with AMI who underwent percutaneous coronary intervention (PCI) during index admission, the mortality rate within 30 days was insignificant (6.3% vs. 6.4%, p = 0.70) but mortalities within 1 year (15.2% vs. 11.6%, p < 0.01), 3 years (24.1% vs. 17.2%, p < 0.01), and 5 years (32.2% vs. 22.6%, p < 0.01) were significantly higher in diabetic patients. CONCLUSIONS The average patient length of hospital stay and medical cost during admission were significantly higher in diabetic patients. Additionally, the difference in mortality rate within 30 days after AMI was insignificant between diabetic and non-diabetic patients. Also, long-term mortality after AMI was significantly higher in diabetic patients. KEY WORDS Acute myocardial infarction; Diabetes mellitus; Length of hospital stay; Medical cost; Mortality; National health insurance.