title: Assessing quality of diabetes care by measuring longitudinal changes in hemoglobin A1c in the Veterans Health Administration.
abstract: BACKGROUND
  A1c levels are widely used to assess quality of diabetes care provided by health care systems. Currently, cross-sectional measures are commonly used for such assessments.
  
  
  OBJECTIVE
  To study within-patient longitudinal changes in A1c levels at Veterans Health Administration (VHA) facilities as an alternative to cross-sectional measures of quality of diabetes care.
  
  
  METHODS
  Longitudinal study using institutional data on individual patient A1c level over time (October 1, 1998-September 30, 2000) with time variant and invariant covariates.
  
  
  METHODS
  One hundred and twenty-five VHA facilities nationwide, October 1, 1998-September 30, 2000.
  
  
  METHODS
  Diabetic veteran users with A1c measurement performed using National Glycosylated Hemoglobin Standardization Project certified A1c lab assay methods.
  
  
  METHODS
  Characteristics unlikely to reflect quality of care, but known to influence A1c levels, demographics, and baseline illness severity.
  
  
  METHODS
  Monthly change in A1c for average patient cared for at each facility.
  
  
  RESULTS
  The preponderance of facilities showed monthly declines in within-patient A1c over the study period (mean change of -0.0148 A1c units per month, range -0.074 to 0.042). Individual facilities varied in their monthly change, with 105 facilities showing monthly declines (70 significant at .05 level) and 20 showing monthly increases (5 significant at .05 level). Case-mix adjustment resulted in modest changes (mean change of -0.0131 case-mix adjusted A1c units per month, range -0.079 to 0.043). Facilities were ranked from worst to best, with attached 90 percent confidence intervals. Among the bottom 10 ranked facilities, four remained within the bottom decile with 90 percent confidence.
  
  
  CONCLUSIONS
  There is substantial variation in facility-level longitudinal changes in A1c levels. We propose that evaluation of change in A1c levels over time can be used as a new measure to reflect quality of care provided to populations of individuals with chronic disease.
authors.affiliation: Deep South Center on Effectiveness at the Birmingham VA Medical Center and the University of Alabama, 35294, USA.
authors.forename: Wes
authors.initials: W
authors.lastname: Thompson
authors.forename: Hongwei
authors.initials: H
authors.lastname: Wang
authors.forename: Minge
authors.initials: M
authors.lastname: Xie
authors.forename: John
authors.initials: J
authors.lastname: Kolassa
authors.forename: Mangala
authors.initials: M
authors.lastname: Rajan
authors.forename: Chin-Lin
authors.initials: CL
authors.lastname: Tseng
authors.forename: Stephen
authors.initials: S
authors.lastname: Crystal
authors.forename: Quanwu
authors.initials: Q
authors.lastname: Zhang
authors.forename: Yehuda
authors.initials: Y
authors.lastname: Vardi
authors.forename: Leonard
authors.initials: L
authors.lastname: Pogach
authors.forename: Monika M
authors.initials: MM
authors.lastname: Safford
mesh_terms: D000368:Aged; D015897:Comorbidity; D003920:Diabetes Mellitus / Q000097:blood* / Q000628:therapy*; D005260:Female; D006442:Glycated Hemoglobin / Q000032:analysis*; D006302:Health Services Research; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D011787:Quality of Health Care / Q000592:standards*; D012720:Severity of Illness Index; D012959:Socioeconomic Factors; D014481:United States; D014493:United States Department of Veterans Affairs / Q000592:standards*
chemical_list: D006442:Glycated Hemoglobin