title: Glycemic control paradox: Poor glycemic control associated with higher one-year and eight-year risks of all-cause hospitalization but lower one-year risk of hypoglycemia in patients with type 2 diabetes.
abstract: OBJECTIVE
  The relationship between glycemic control and adverse outcomes found in a population with diabetes has seldom been evaluated in patients with type 2 diabetes. We explored the association between hemoglobin A1c (HbA1c) and hospitalization risks within one-year and eight-year follow-up periods.
  
  
  METHODS
  We conducted a retrospective cohort study on 57,061 patients with type 2 diabetes from National Diabetes Case Management Program during 2002-2004 in Taiwan. HbA1c at baseline and in-hospital mortality, all-cause and cause-specific hospitalization over one year and eight years were analyzed.
  
  
  RESULTS
  After multivariate adjustment, one-year risk was higher for cases with HbA1c level <6%, 9-10%, ≥10% versus 6-7% for all-cause hospitalization (hazard ratio [HR]: 1.11, 95% confidence interval [CI]: 1.03-1.20; 1.08, 1.01-1.16, and 1.19, 1.12-1.26, respectively) and for ≥10% for diabetes-related hospitalization (1.68, 1.46-1.92). Yet each 1-step increment in HbA1c category (<6.0, 6.0-6.9, 7.0-7.9, 8.0-8.9, 9.0-9.9 and ≥10.0%) showed linkage with lower risk of hypoglycemia hospitalization (0.81, 95% CI: 0.74-0.88). For eight-year risk, subjects with HbA1c level <6%, and ≥10% were more likely to have in-hospitality mortality (1.16, 1.03-1.31, and 1.23, 1.11-1.35, respectively). Each 1-step increment in HbA1c category showed an association with higher risks of all-cause and diabetes-related hospitalization (1.04, 1.03-1.05, and 1.15, 1.14-1.17, respectively).
  
  
  CONCLUSIONS
  Higher HbA1c level correlated with lower one-year risk due to hypoglycemia hospitalization but increased one-year and eight-year risks due to all-cause and diabetes-specific hospitalization among Chinese people with type 2 diabetes in Taiwan. Future study must ascertain how to meet HbA1c targets and improve outcome without risk to this population.
authors.affiliation: Graduate Institute of Biostatistics, College of Public Health, China Medical University, Taichung, Taiwan; Department of Healthcare Administration, College of Health Science, Asia University, Taichung, Taiwan.
authors.forename: Tsai-Chung
authors.initials: TC
authors.lastname: Li
authors.affiliation: Graduate Institute of Clinical Medical Science, College of Medicine, China Medical University, Taichung, Taiwan; Department of Epidemiology, University of Michigan, Ann Arbor, MI, USA.
authors.forename: Sharon L R
authors.initials: SL
authors.lastname: Kardia
authors.affiliation: Department of Medical Research, China Medical University Hospital, Taichung, Taiwan; School of Medicine, College of Medicine, China Medical University, Taichung, Taiwan.
authors.forename: Chia-Ing
authors.initials: CI
authors.lastname: Li
authors.affiliation: Division of Endocrinology and Metabolism, Department of Medicine, China Medical University Hospital, Taichung, Taiwan; School of Chinese Medicine, College of Chinese Medicine, China Medical University, Taichung, Taiwan.
authors.forename: Ching-Chu
authors.initials: CC
authors.lastname: Chen
authors.affiliation: Department of Medical Research, China Medical University Hospital, Taichung, Taiwan; School of Medicine, College of Medicine, China Medical University, Taichung, Taiwan; Department of Family Medicine, China Medical University Hospital, Taichung, Taiwan.
authors.forename: Chiu-Shong
authors.initials: CS
authors.lastname: Liu
authors.affiliation: Graduate Institute of Biostatistics, College of Public Health, China Medical University, Taichung, Taiwan.
authors.forename: Sing-Yu
authors.initials: SY
authors.lastname: Yang
authors.affiliation: Management Office for Health Data, China Medical University Hospital, Taichung, Taiwan.
authors.forename: Chin-Shin
authors.initials: CS
authors.lastname: Muo
authors.affiliation: Department of Epidemiology, University of Michigan, Ann Arbor, MI, USA.
authors.forename: Patricia A
authors.initials: PA
authors.lastname: Peyser
authors.affiliation: Department of Medical Research, China Medical University Hospital, Taichung, Taiwan; School of Medicine, College of Medicine, China Medical University, Taichung, Taiwan; Department of Family Medicine, China Medical University Hospital, Taichung, Taiwan. Electronic address: cclin@mail.cmuh.org.tw.
authors.forename: Cheng-Chieh
authors.initials: CC
authors.lastname: Lin
mesh_terms: D000368:Aged; D001786:Blood Glucose / Q000378:metabolism*; D015331:Cohort Studies; D003924:Diabetes Mellitus, Type 2 / Q000188:drug therapy* / Q000401:mortality; D005260:Female; D005500:Follow-Up Studies; D006442:Glycated Hemoglobin / Q000032:analysis / Q000378:metabolism; D017052:Hospital Mortality; D006760:Hospitalization / Q000706:statistics & numerical data*; D006801:Humans; D007003:Hypoglycemia / Q000188:drug therapy* / Q000401:mortality; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012306:Risk; D013624:Taiwan / Q000453:epidemiology; D016896:Treatment Outcome
chemical_list: D001786:Blood Glucose; D006442:Glycated Hemoglobin
keywords: Glycemic control; Hospitalization; Hypoglycemia; Type 2 diabetes