Prognosis After First-Ever Myocardial Infarction in Type 1 Diabetes Is Strongly Affected by Chronic Kidney Disease

Abstract

OBJECTIVE To study prognosis after a first-ever myocardial infarction (MI) in type 1 diabetes, as well as how different MI- and diabetes-related factors affect the prognosis and risk of secondary cardiovascular events. RESEARCH DESIGN AND METHODS In this observational follow-up study of 4,217 individuals from the Finnish Diabetic Nephropathy (FinnDiane) Study with no prior MI or coronary revascularization, we verified 253 (6.0%) MIs from medical records or death certificates. Mortality from cardiovascular or diabetes-related cause was our main end point, whereas hospitalization due to heart failure, coronary revascularization, and recurrent MI were secondary end points, while accounting for death as a competing risk. RESULTS Of the individuals studied, 187 (73.9%) died during the median post-MI follow-up of 3.07 (interquartile range 0.02–8.45) years. Independent risk factors for cardiovascular and diabetes-related mortality were estimated glomerular filtration rate categories grade 3 (G3) (hazard ratio [HR] 3.27 [95% CI 1.76–6.08]), G4 (3.62 [1.69–7.73]), and G5 (4.03 [2.24–7.26]); prior coronary heart disease diagnosis (1.50 [1.03–2.20]); and older age at MI (1.03 [1.00–1.05]). Factors associated with lower mortality were acute revascularization (HR 0.35 [95% CI 0.18–0.72]) and subacute revascularization (0.39 [0.26–0.59]). In Fine and Gray competing risk analyses, kidney failure was associated with a higher risk of recurrent MI (subdistribution HR 3.27 [95% CI 2.01–5.34]), heart failure (3.76 [2.46–5.76]), and coronary revascularization (3.04 [1.89–4.90]). CONCLUSIONS Individuals with type 1 diabetes have a high cardiovascular and diabetes-related mortality after their first-ever MI. In particular, poor kidney function is associated with high mortality and excessive risk of secondary cardiovascular events.