The impact of kidney function on long-term outcomes following myocardial infarction in patients with diabetes mellitus

Background Diabetes mellitus (DM), reduced kidney function (KF) and previous cardiovascular disease (CVD) are associated with an increased risk of adverse prognosis and recurrent cardiovascular events after myocardial infarction (MI). There are little data about the prognosis in patients with DM in whom MI is the first CVD event. The aim of this study was to analyze the impact of kidney function on the occurrence of major adverse cardiovascular events (MACE) following MI in patients with DM and no previous CVD events. Method we analyzed 496 STEMI patients with DM and without previous MI, angina, stroke or peripheral artery disease. All patients were treated with primary PCI. Kidney function was assessed at hospital admission (before iodine contrast administration) by calculating estimated glomerular filtration rate (eGFR). Reduced KF was defined as eGFR <90ml/min/m2 and it was staged into mildly (eGFR 60-89ml/min/m2), moderated (eGFR 30-59ml/min/m2) and severely reduced (eGFR 15-29ml/min/m2). Composite end point MACE included cardiovascular mortality, non-fatal recurrent infarction, target vessel revascularization and non-fatal stroke. The follow-up period was 8 years. Results The median age of analyzed was 58 years (interquartile range 51, 68) and 186(36.9%) patients were females. Reduced KF was present in 308 (62%) patients and among them 59% had mildly reduced KF, 31.4% had moderately reduced KF and 9.6% had severely reduced KF. Patients with reduced KF have significantly higher MACE rate as compared with patients with preserved KF. MACE rate was higher with declining KF, as shown in Figure 1. Cox regression model was used for defining independent predictors for the occurrence of MACE. Variables defined in univariable model as predictors of MACE and clinically relevant variables based on data from literature were included in the multivariable model. We identified six independent predictors: moderated and severely reduced KF (HR 3.12 95%CI 1.58-6.91 and HR 5.22 95%CI 1.68-12.7 respectively); pre-discharge ejection fraction <50% (HR 0.92, 95%CI 0,89-0,98); new-onset atrial fibrillation (HR 2.02, 95%CI 1.08-3.27); left-main stenosis (HR 2.01, 95%CI 1.02-4.02); heart failure at admission (HR 1.84, 95%CI 1.18-3.331) and post-procedural flow TIMI<3 (1.68 95%CI 1.01-2.89). Conclusion Moderately and severely reduced kidney function were the strongest independent predictors for 8-year MACE after MI in analyzed patients with DM and no previous CVD events, while mildly reduced kidney function had no independent impact on the occurrence of long-term adverse events.