title: Prognostic significance of hemoglobin A1c level in patients hospitalized with coronary artery disease. A systematic review and meta-analysis.
abstract: BACKGROUND
  The prognostic value of hemoglobin A1c (HbA1c) in coronary artery disease (CAD) remains controversial. Herein, we conducted a systematic review to quantify the association between elevated HbA1c levels and all-cause mortality among patients hospitalized with CAD.
  
  
  METHODS
  A systematic search of electronic databases (PubMed, EMBASE, OVID, Web of Science, The Cochrane Library) for studies published from 1970 to May 2011 was performed. Cohort, case-control studies, and randomized controlled trials that examined the effect of HbA1c on all-cause mortality were included.
  
  
  RESULTS
  Twenty studies met final inclusion criteria (total n = 13, 224). From the pooled analyses, elevated HbA1c level was significantly associated with increased short-term (OR 2.32, 95% CI, 1.61 to 3.35) and long-term (OR 1.54, 95% CI, 1.23 to 1.94) mortality risk. Subgroup analyses suggested elevated HbA1c level predicted higher mortality risk in patients without diabetes (OR 1.84, 95% CI, 1.51 to 2.24). In contrast, in patients with diabetes, elevated HbA1c level was not associated with increased risk of mortality (OR 0.95, 95% CI, 0.70 to 1.28). In a risk-adjusted sensitivity analyses, elevated HbA1c was also associated with a significantly high risk of adjusted mortality in patients without diabetes (adjusted OR 1.49, 95% CI, 1.24 to 1.79), but had a borderline effect in patients with diabetes (adjusted OR 1.05, 95% CI, 1.00 to 1.11).
  
  
  CONCLUSIONS
  Our findings demonstrate that elevated HbA1c level is an independent risk factor for mortality in CAD patients without diabetes, but not in patients with established diabetes. Prospective studies should further investigate whether glycemic control might improve outcomes in CAD patients without previously diagnosed diabetes.
authors.affiliation: Emergency Department, Cardiovascular Institute and Fuwai Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, (167 Beilishilu Road), Beijing, (100037), China.
authors.forename: Yao
authors.initials: Y
authors.lastname: Liu
authors.forename: Yan-min
authors.initials: YM
authors.lastname: Yang
authors.forename: Jun
authors.initials: J
authors.lastname: Zhu
authors.forename: Hui-qiong
authors.initials: HQ
authors.lastname: Tan
authors.forename: Yan
authors.initials: Y
authors.lastname: Liang
authors.forename: Jian-dong
authors.initials: JD
authors.lastname: Li
mesh_terms: D003324:Coronary Artery Disease / Q000097:blood* / Q000175:diagnosis*; D006442:Glycated Hemoglobin / Q000378:metabolism* / Q000502:physiology; D006760:Hospitalization / Q000639:trends; D006801:Humans; D011379:Prognosis; D016032:Randomized Controlled Trials as Topic / Q000639:trends
chemical_list: D006442:Glycated Hemoglobin; C517652:hemoglobin A1c protein, human
references.citation: QJM. 2006 Apr;99(4):237-43
references.pmid: 16504985
references.citation: Lancet. 1998 Sep 12;352(9131):837-53
references.pmid: 9742976
references.citation: Scand Cardiovasc J. 2008 Dec;42(6):392-8
references.pmid: 18609043
references.citation: Am Heart J. 2005 Nov;150(5):1000-6
references.pmid: 16290985
references.citation: Am Heart J. 2006 Jan;151(1):91
references.pmid: 16368297
references.citation: JAMA. 2000 Apr 19;283(15):2008-12
references.pmid: 10789670
references.citation: Eur Heart J. 2005 Jan;26(1):58-64
references.pmid: 15615800
references.citation: J Am Coll Cardiol. 2009 Jul 28;54(5):422-8
references.pmid: 19628117
references.citation: Cardiovasc Diabetol. 2011 Jun 30;10:58
references.pmid: 21714932
references.citation: Circulation. 2005 Feb 15;111(6):754-60
references.pmid: 15699267
references.citation: Diabet Med. 2004 Apr;21(4):305-10
references.pmid: 15049930
references.citation: Neth J Med. 2007 Mar;65(3):95-100
references.pmid: 17387235
references.citation: J Am Coll Cardiol. 2000 May;35(6):1502-12
references.pmid: 10807453
references.citation: J Thorac Cardiovasc Surg. 2008 Sep;136(3):631-40
references.pmid: 18805264
references.citation: Am J Cardiol. 2005 Jul 15;96(2):183-6
references.pmid: 16018838
references.citation: Diabetes Care. 2009 Jul;32(7):1327-34
references.pmid: 19502545
references.citation: BMJ. 2001 Jul 28;323(7306):224-8
references.pmid: 11473921
references.citation: Lancet. 1984 Jun 9;1(8389):1264-7
references.pmid: 6144976
references.citation: Cardiology. 2010;116(1):51-7
references.pmid: 20453503
references.citation: Eur Heart J. 2004 Nov;25(21):1891-7
references.pmid: 15522467
references.citation: JAMA. 2007 Aug 15;298(7):765-75
references.pmid: 17699010
references.citation: Diabetes Care. 2005 Oct;28(10):2551-3
references.pmid: 16186299
references.citation: Eur Heart J. 2006 Oct;27(20):2413-9
references.pmid: 17000629
references.citation: Lancet. 1983 Jul 23;2(8343):179-81
references.pmid: 6135025
references.citation: J Cardiol. 2011 Mar;57(2):181-6
references.pmid: 21185154
references.citation: Circulation. 2002 Jun 11;105(23):2696-8
references.pmid: 12057978
references.citation: Am J Cardiol. 2003 Dec 1;92(11):1282-6
references.pmid: 14636904
references.citation: Am J Prev Med. 2001 Apr;20(3 Suppl):21-35
references.pmid: 11306229
references.citation: Diabetes Care. 2005 Jan;28 Suppl 1:S4-S36
references.pmid: 15618112
references.citation: N Engl J Med. 2008 Jun 12;358(24):2545-59
references.pmid: 18539917
references.citation: Diabetes Care. 1991 Mar;14(3):173-94
references.pmid: 2044434
references.citation: Am J Cardiol. 2007 Feb 19;99(4A):6B-14B
references.pmid: 17307054
references.citation: JAMA. 2006 Apr 12;295(14):1681-7
references.pmid: 16609090
references.citation: Ann Thorac Surg. 2008 Nov;86(5):1431-7
references.pmid: 19049726
references.citation: Circulation. 2008 Mar 25;117(12):1610-9
references.pmid: 18299505
references.citation: J Intern Med. 2003 Nov;254(5):494-503
references.pmid: 14535972
references.citation: N Engl J Med. 2008 Oct 9;359(15):1565-76
references.pmid: 18784091
references.citation: Lancet. 2009 May 23;373(9677):1765-72
references.pmid: 19465231
references.citation: Circulation. 1999 May 25;99(20):2626-32
references.pmid: 10338454
references.citation: Ann Thorac Cardiovasc Surg. 2009 Feb;15(1):18-22
references.pmid: 19262445
references.citation: J Intern Med. 2010 Nov;268(5):471-82
references.pmid: 20804517
references.citation: Eur J Cardiothorac Surg. 2011 Apr;39(4):484-9
references.pmid: 21087870
references.citation: N Engl J Med. 2009 Jan 8;360(2):129-39
references.pmid: 19092145
references.citation: Cardiovasc Diabetol. 2010 Jun 02;9:22
references.pmid: 20525192
references.citation: Coron Artery Dis. 2011 May;22(3):131-7
references.pmid: 21394027
references.citation: Diabet Med. 2011 Jan;28(1):73-80
references.pmid: 21166848
references.citation: Circulation. 2005 Jun 14;111(23):3078-86
references.pmid: 15939812
references.citation: N Engl J Med. 2010 Mar 4;362(9):800-11
references.pmid: 20200384
references.citation: Am Heart J. 2007 Sep;154(3):470-6
references.pmid: 17719292
references.citation: Am J Cardiol. 2009 Jul 1;104(1):41-5
references.pmid: 19576319
references.citation: BMJ. 2000 Aug 12;321(7258):405-12
references.pmid: 10938048
references.citation: Can J Cardiol. 2010 Mar;26(3):151-4
references.pmid: 20352135
references.citation: Postgrad Med J. 1998 Aug;74(874):480-1
references.pmid: 9926122
references.citation: Can J Cardiol. 2008 May;24(5):375-8
references.pmid: 18464942
references.citation: Am Heart J. 2001 Jan;141(1):117-23
references.pmid: 11136496
references.citation: Diabetologia. 2009 Nov;52(11):2288-98
references.pmid: 19655124