Advertisement

Blood urea nitrogen has additive value beyond estimated glomerular filtration rate for prediction of long-term mortality in patients with acute myocardial infarction

      Abstract

      Objectives

      Blood urea nitrogen (BUN) has been shown to independently predict short- and intermediate-term outcomes in patients with acute myocardial infarction (AMI). We aimed to assess the additive predictive value of BUN beyond estimated glomerular filtration rate (eGFR) in AMI patients with an 8.6-year follow-up.

      Methods

      This retrospective, observational single-centre study included 1332 consecutive AMI patients (median age 64 years, 58.4% male). BUN, creatinine and eGFR were determined at hospital admission.

      Results

      During a median follow-up of 8.6 years (interquartile range [IQR] 4.0–11.6), 408 patients (30.6%) experienced the study endpoint of cardiovascular mortality. BUN (median 17.0 mg/dL [IQR 13.5–22.7]) was a significant predictor of cardiovascular mortality in univariate Cox regression (hazard ratio (HR) per 1 standard deviation increase 2.10, 95% confidence interval [CI] 1.94–2.28, p < .001). This association remained significant after multivariable adjustment for demographics, clinical variables and eGFR (adjusted HR 1.52 [CI 1.16–2.00, p = .003]). The association between BUN and outcome was more pronounced in patients with eGFR >60 mL/min/1.73m2 (HR 2.81 [CI 2.20–3.58, p < .001]). The discriminatory abilities (Harrell's C-statistic) for BUN, eGFR and creatinine were 0.75, 0.76 and 0.67, respectively. The addition of BUN to eGFR significantly improved the C-statistic (0.78, p for comparison = 0.017), net reclassification (23.7%, p < .001) and integrated discrimination (2.9%, p < .001).

      Conclusions

      Circulating BUN on admission is an independent predictor of long-term cardiovascular mortality in AMI patients and adds predictive power beyond eGFR. BUN reflects not only kidney function, but also acute haemodynamic and neurohumoral alterations during AMI, and may help to identify high-risk patients.

      Keywords

      Abbreviations:

      AMI (acute myocardial infarction), BUN (blood urea nitrogen), CI (confidence interval), CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration), eGFR (estimated glomerular filtration rate), HR (hazard ratio), IDI (integrated discrimination improvement), IQR (interquartile range), NRI (net reclassification improvement), NT-proBNP (N-terminal pro-B-type natriuretic peptide), SD (standard deviation), STEMI (ST-elevation myocardial infarction)
      To read this article in full you will need to make a payment

      Purchase one-time access:

      Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online access
      One-time access price info
      • For academic or personal research use, select 'Academic and Personal'
      • For corporate R&D use, select 'Corporate R&D Professionals'

      Subscribe:

      Subscribe to European Journal of Internal Medicine
      Already a print subscriber? Claim online access
      Already an online subscriber? Sign in
      Institutional Access: Sign in to ScienceDirect

      References

        • Anavekar N.S.
        • McMurray J.J.
        • Velazquez E.J.
        • Solomon S.D.
        • Kober L.
        • Rouleau J.L.
        • et al.
        Relation between renal dysfunction and cardiovascular outcomes after myocardial infarction.
        N Engl J Med. 2004; 351: 1285-1295
        • Gibson C.M.
        • Pinto D.S.
        • Murphy S.A.
        • Morrow D.A.
        • Hobbach H.P.
        • Wiviott S.D.
        • et al.
        Association of creatinine and creatinine clearance on presentation in acute myocardial infarction with subsequent mortality.
        J Am Coll Cardiol. 2003; 42: 1535-1543
        • Al Suwaidi J.
        • Reddan D.N.
        • Williams K.
        • Pieper K.S.
        • Harrington R.A.
        • Califf R.M.
        • et al.
        Prognostic implications of abnormalities in renal function in patients with acute coronary syndromes.
        Circulation. 2002; 106: 974-980
        • Kirtane A.J.
        • Leder D.M.
        • Waikar S.S.
        • Chertow G.M.
        • Ray K.K.
        • Pinto D.S.
        • et al.
        Serum blood urea nitrogen as an independent marker of subsequent mortality among patients with acute coronary syndromes and normal to mildly reduced glomerular filtration rates.
        J Am Coll Cardiol. 2005; 45: 1781-1786
        • Smith G.L.
        • Shlipak M.G.
        • Havranek E.P.
        • Foody J.M.
        • Masoudi F.A.
        • Rathore S.S.
        • et al.
        Serum urea nitrogen, creatinine, and estimators of renal function: mortality in older patients with cardiovascular disease.
        Arch Intern Med. 2006; 166: 1134-1142
        • Saygitov R.T.
        • Glezer M.G.
        • Semakina S.V.
        Blood urea nitrogen and creatinine levels at admission for mortality risk assessment in patients with acute coronary syndromes.
        Emerg Med J. 2010; 27: 105-109
        • Aronson D.
        • Hammerman H.
        • Beyar R.
        • Yalonetsky S.
        • Kapeliovich M.
        • Markiewicz W.
        • et al.
        Serum blood urea nitrogen and long-term mortality in acute ST-elevation myocardial infarction.
        Int J Cardiol. 2008; 127: 380-385
        • Usberti M.
        • Federico S.
        • Di Minno G.
        • Ungaro B.
        • Ardillo G.
        • Pecoraro C.
        • et al.
        Effects of angiotensin II on plasma ADH, prostaglandin synthesis, and water excretion in normal humans.
        Am J Physiol. 1985; 248: F254-F259
        • Fonarow G.C.
        • Adams Jr., K.F.
        • Abraham W.T.
        • Yancy C.W.
        • Boscardin W.J.
        • Adhere Scientific Advisory Committee SG
        • et al.
        Risk stratification for in-hospital mortality in acutely decompensated heart failure: classification and regression tree analysis.
        JAMA. 2005; 293: 572-580
        • Aronson D.
        • Mittleman M.A.
        • Burger A.J.
        Elevated blood urea nitrogen level as a predictor of mortality in patients admitted for decompensated heart failure.
        Am J Med. 2004; 116: 466-473
        • Thygesen K.
        • Alpert J.S.
        • Jaffe A.S.
        • Simoons M.L.
        • Chaitman B.R.
        • White H.D.
        • et al.
        Third universal definition of myocardial infarction.
        Eur Heart J. 2012; 33: 2551-2567
        • Levey A.S.
        • Stevens L.A.
        • Schmid C.H.
        • Zhang Y.L.
        • Castro 3rd, A.F.
        • Feldman H.I.
        • et al.
        A new equation to estimate glomerular filtration rate.
        Ann Intern Med. 2009; 150: 604-612
        • Steyerberg E.W.
        • Vickers A.J.
        • Cook N.R.
        • Gerds T.
        • Gonen M.
        • Obuchowski N.
        • et al.
        Assessing the performance of prediction models: a framework for traditional and novel measures.
        Epidemiology. 2010; 21: 128-138
        • Heagerty P.J.
        • Lumley T.
        • Pepe M.S.
        Time-dependent ROC curves for censored survival data and a diagnostic marker.
        Biometrics. 2000; 56: 337-344
        • Normand S.T.
        • Glickman M.E.
        • Sharma R.G.
        • McNeil B.J.
        Using admission characteristics to predict short-term mortality from myocardial infarction in elderly patients. Results from the cooperative cardiovascular project.
        JAMA. 1996; 275: 1322-1328
        • Korhonen P.E.
        • Kautiainen H.
        • Jarvenpaa S.
        • Kivela S.L.
        Time to change the glomerular filtration rate estimating formula in primary care?.
        Eur J Intern Med. 2012; 23: 355-357
        • Stevens L.A.
        • Schmid C.H.
        • Greene T.
        • Zhang Y.L.
        • Beck G.J.
        • Froissart M.
        • et al.
        Comparative performance of the CKD epidemiology collaboration (CKD-EPI) and the modification of diet in renal disease (MDRD) study equations for estimating GFR levels above 60 mL/min/1.73 m2.
        Am J Kidney Dis. 2010; 56: 486-495
        • Swedko P.J.
        • Clark H.D.
        • Paramsothy K.
        • Akbari A.
        Serum creatinine is an inadequate screening test for renal failure in elderly patients.
        Arch Intern Med. 2003; 163: 356-360
        • Rott D.
        • Klempfner R.
        • Goldenberg I.
        • Matetzky S.
        • Elis A.
        Temporal trends in the outcomes of patients with acute myocardial infarction associated with renal dysfunction over the past decade.
        Eur J Intern Med. 2016; 29: 88-92
        • Berger A.K.
        • Duval S.
        • Krumholz H.M.
        Aspirin, beta-blocker, and angiotensin-converting enzyme inhibitor therapy in patients with end-stage renal disease and an acute myocardial infarction.
        J Am Coll Cardiol. 2003; 42: 201-208
        • McCullough P.A.
        • Sandberg K.R.
        • Borzak S.
        • Hudson M.P.
        • Garg M.
        • Manley H.J.
        Benefits of aspirin and beta-blockade after myocardial infarction in patients with chronic kidney disease.
        Am Heart J. 2002; 144: 226-232
        • Dossetor J.B.
        Creatininemia versus uremia. The relative significance of blood urea nitrogen and serum creatinine concentrations in azotemia.
        Ann Intern Med. 1966; 65: 1287-1299