title: Serum glycated hemoglobin level as a predictor of atrial fibrillation: A systematic review with meta-analysis and meta-regression.
abstract: OBJECTIVE
  Glycated hemoglobin (HbA1c) is a long-term measure of glucose control. Although recent studies demonstrated a potential association between HbA1c levels and the risk of atrial fibrillation (AF), the results have been inconsistent. The aim of this meta-analysis is to evaluate the utility of HbA1c level in predicting AF.
  
  
  METHODS
  PubMed and the Cochrane Library databases were searched for relevant studies up to March 2016. Prospective cohort studies and retrospective case-control studies were included. Relative risk (RR) or odds ratio (OR) with 95% confidence intervals (CIs) of AF development were determined for different HbA1c levels. The random effect model was conducted according to the test of heterogeneity among studies. Subgroup analyses and meta-regression models were carried out to identify potential sources of heterogeneity.
  
  
  RESULTS
  Eight prospective cohort studies with 102,006 participants and 6 retrospective case-control studies with 57,669 patients were finally included in the meta-analysis. In the primary meta-analysis, HbA1c levels were not associated with an increased risk of AF whether as a continuous (RR, 1.06; 95% CI, 0.96-1.18) or categorical variable (RR, 0.99; 95% CI, 0.83-1.18). Nevertheless, prospective studies showed about 10% increased risk of AF with elevated HbA1c levels both as a continuous (RR, 1.11; 95% CI, 1.06-1.16) and as a categorical variable (RR, 1.09; 95% CI, 1.00-1.18). In subgroup analyses, pooled results from studies with longer follow-up durations, published after 2012, aged < 63 years, with exclusion of cardiac surgery patients demonstrated an increased risk of AF for every 1% increase in HbA1c levels, while studies conducted in the United States with longer follow-up (more than 96 months), larger sample size and higher quality score (≥6) showed an increased risk of AF for higher HbA1c level as a categorical variable.
  
  
  CONCLUSIONS
  Elevated serum HbA1c levels may be associated with an increased risk of AF, but further data are needed. Serum HbA1c levels might be considered as a potential biomarker for prediction of AF.
authors.affiliation: Tianjin Key Laboratory of Ionic-Molecular Function of Cardiovascular disease, Department of Cardiology, Tianjin Institute of Cardiology, Second Hospital of Tianjin Medical University, Tianjin, China.|School of Public Health, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
authors.forename: Wenwei
authors.initials: W
authors.lastname: Qi
authors.affiliation: Tianjin Key Laboratory of Ionic-Molecular Function of Cardiovascular disease, Department of Cardiology, Tianjin Institute of Cardiology, Second Hospital of Tianjin Medical University, Tianjin, China.
authors.forename: Nixiao
authors.initials: N
authors.lastname: Zhang
authors.affiliation: First Department of Cardiology, University of Ioannina Medical School, Ioannina, Greece.
authors.forename: Panagiotis
authors.initials: P
authors.lastname: Korantzopoulos
authors.affiliation: Second Department of Cardiology, Laboratory of Cardiac Electrophysiology, "Evangelismos" General Hospital of Athens, Athens, Greece.
authors.forename: Konstantinos P
authors.initials: KP
authors.lastname: Letsas
authors.affiliation: State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
authors.forename: Min
authors.initials: M
authors.lastname: Cheng
authors.affiliation: Department of Endocrinology and Metabolism, the Third Central Hospital of Tianjin, Tianjin, China.
authors.forename: Fusheng
authors.initials: F
authors.lastname: Di
authors.affiliation: Department of Medicine and Therapeutics, Chinese University of Hong Kong, Hong Kong, Special Administrative Region, P.R. China.|Li Ka Shing Institute of Health Sciences, Chinese University of Hong Kong, Hong Kong, Special Administrative Region, P.R. China.
authors.forename: Gary
authors.initials: G
authors.lastname: Tse
authors.affiliation: Tianjin Key Laboratory of Ionic-Molecular Function of Cardiovascular disease, Department of Cardiology, Tianjin Institute of Cardiology, Second Hospital of Tianjin Medical University, Tianjin, China.
authors.forename: Tong
authors.initials: T
authors.lastname: Liu
authors.affiliation: Tianjin Key Laboratory of Ionic-Molecular Function of Cardiovascular disease, Department of Cardiology, Tianjin Institute of Cardiology, Second Hospital of Tianjin Medical University, Tianjin, China.
authors.forename: Guangping
authors.initials: G
authors.lastname: Li
mesh_terms: D001281:Atrial Fibrillation / Q000097:blood* / Q000175:diagnosis* / Q000453:epidemiology; D015415:Biomarkers; D006442:Glycated Hemoglobin; D006801:Humans; D016017:Odds Ratio; D011379:Prognosis; D017594:Publication Bias; D018570:Risk Assessment
chemical_list: D015415:Biomarkers; D006442:Glycated Hemoglobin