title: Glycemic control, complications, and death in older diabetic patients: the diabetes and aging study.
abstract: OBJECTIVE
  To identify the range of glycemic levels associated with the lowest rates of complications and mortality in older diabetic patients.
  
  
  METHODS
  We conducted a retrospective cohort study (2004-2008) of 71,092 patients with type 2 diabetes, aged ≥60 years, enrolled in Kaiser Permanente Northern California. We specified Cox proportional hazards models to evaluate the relationships between baseline glycated hemoglobin (A1C) and subsequent outcomes (nonfatal complications [acute metabolic, microvascular, and cardiovascular events] and mortality).
  
  
  RESULTS
  The cohort (aged 71.0 ± 7.4 years [means ± SD]) had a mean A1C of 7.0 ± 1.2%. The risk of any nonfatal complication rose monotonically for levels of A1C >6.0% (e.g., adjusted hazard ratio 1.09 [95% CI 1.02-1.16] for A1C 6.0-6.9% and 1.86 [1.63-2.13] for A1C ≥11.0%). Mortality had a U-shaped relationship with A1C. Compared with the risk with A1C <6.0%, mortality risk was lower for A1C levels between 6.0 and 9.0% (e.g., 0.83 [0.76-0.90] for A1C 7.0-7.9%) and higher at A1C ≥11.0% (1.31 [1.09-1.57]). Risk of any end point (complication or death) became significantly higher at A1C ≥8.0%. Patterns generally were consistent across age-groups (60-69, 70-79, and ≥80 years).
  
  
  CONCLUSIONS
  Observed relationships between A1C and combined end points support setting a target of A1C <8.0% for older patients, with the caution that A1Cs <6.0% were associated with increased mortality risk. Additional research is needed to evaluate the low A1C-mortality relationship, as well as protocols for individualizing diabetes care.
authors.affiliation: Section of General Internal Medicine, University of Chicago, Chicago, Illinois, USA. ehuang@medicine.bsd.uchicago.edu
authors.forename: Elbert S
authors.initials: ES
authors.lastname: Huang
authors.forename: Jennifer Y
authors.initials: JY
authors.lastname: Liu
authors.forename: Howard H
authors.initials: HH
authors.lastname: Moffet
authors.forename: Priya M
authors.initials: PM
authors.lastname: John
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Karter
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000375:Aging; D001786:Blood Glucose / Q000378:metabolism*; D002140:California / Q000453:epidemiology; D002318:Cardiovascular Diseases / Q000401:mortality; D015331:Cohort Studies; D003924:Diabetes Mellitus, Type 2 / Q000150:complications* / Q000401:mortality*; D006442:Glycated Hemoglobin / Q000378:metabolism*; D006801:Humans; D007676:Kidney Failure, Chronic / Q000401:mortality; D008875:Middle Aged; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D016896:Treatment Outcome
chemical_list: D001786:Blood Glucose; D006442:Glycated Hemoglobin