Prevalence and Significance of Unrecognized Renal Dysfunction in Patients with Acute Coronary Syndrome

Background Unrecognized renal insufficiency, defined as estimated glomerular filtration rate <60 mL/min/1.73 m² in the presence of normal serum creatinine, is common among patients with acute coronary syndrome. We aimed to determine the prevalence and clinical significance of unrecognized renal insufficiency in a large unselected population of patients with acute coronary syndrome. Methods The study population consisted of patients with acute coronary syndrome included in the Acute Coronary Syndrome Israeli biennial Surveys during 2000-2013. The estimated glomerular filtration rate was calculated using the simplified Modification of Diet in Renal Disease formula. Patients were stratified into 3 groups: 1) normal renal function (estimated glomerular filtration rates ≥60 mL/min/1/73 m²); 2) unrecognized renal insufficiency (estimated glomerular filtration rates <60 mL/min/1/73 m² with serum creatinine ≤1.2 mg/dL); and 3) recognized renal insufficiency (estimated glomerular filtration rates <60 mL/min/1/73 m² with serum creatinine ≥1.2 mg/dL). The primary endpoint was all-cause mortality at 1 year. Results Included in the study were 12,830 acute coronary syndrome patients. Unrecognized renal insufficiency was present in 2536 (19.8%). Patients with unrecognized renal insufficiency were older and more frequently females. All-cause mortality rates at 1 year were highest among patients with recognized renal insufficiency, followed by patients with unrecognized renal insufficiency, with the lowest mortality rates observed in patients with normal renal function (19.4%, 9.9%, and 3.3%, respectively, P <.0001). Despite their increased risk, patients with renal insufficiency were less frequently referred for coronary angiography and were less commonly treated with guideline-based cardiovascular medications. Conclusions Acute coronary syndrome patients with unrecognized renal insufficiency should be considered as a high-risk population. The question of whether this group would benefit from a more aggressive therapeutic approach should still be evaluated.