Prognostic value of silent myocardial infarction in patients with chronic kidney disease being evaluated for kidney transplantation

Background Patients with advanced chronic kidney disease (CKD) have increased risk of myocardial infarction (MI). Silent MIs (SMIs) are common in CKD patients and carry increased mortality risk. The prevalence and prognostic value of SMI in advanced CKD has not been evaluated. Methods We identified consecutive patients with advanced CKD who were evaluated for renal transplantation at the University of Alabama at Birmingham between June 2004 and January 2006. Clinical MI (CMI) was determined by review of medical records. SMI was defined as ECG evidence of MI without clinical history of MI. The primary end-point was a composite of death, MI, or coronary revascularization censored at time of renal transplantation. Results The cohort included 1007 patients with advanced CKD aged 48 ± 12 years (58% men, 43% diabetes, 75% on dialysis). The prevalence of SMI and CMI was 10.7% and 6.7%, respectively. The only independent predictor of SMI was older age (odds ratio for age ≥ 50 yrs. 2.32, p < 0.001). During a median follow-up of 28 months, 376 (37%) patients experienced the primary outcome (33% death, 2% MI, 5% coronary revascularization). In a multivariable adjusted Cox-regression model, both SMI (adjusted HR 1.58, [1.13–2.20], p = 0.007) and CMI (adjusted HR 1.67 [1.15–2.43], p = 0.007) were independently associated with the primary outcome. Further, both SMI (HR 2.37 [1.15–4.88], p = 0.02) and CMI (HR 4.02 [1.80–8.98], p = 0.001) were associated with increased risk after renal transplantation. Conclusions SMI is more common than CMI in patients with advanced CKD. Both SMI and CMI are associated with increased risk of future cardiovascular events.