title: Patient complexity in quality comparisons for glycemic control: an observational study.
abstract: BACKGROUND
  Patient complexity is not incorporated into quality of care comparisons for glycemic control. We developed a method to adjust hemoglobin A1c levels for patient characteristics that reflect complexity, and examined the effect of using adjusted A1c values on quality comparisons.
  
  
  METHODS
  This cross-sectional observational study used 1999 national VA (US Department of Veterans Affairs) pharmacy, inpatient and outpatient utilization, and laboratory data on diabetic veterans. We adjusted individual A1c levels for available domains of complexity: age, social support (marital status), comorbid illnesses, and severity of disease (insulin use). We used adjusted A1c values to generate VA medical center level performance measures, and compared medical center ranks using adjusted versus unadjusted A1c levels across several thresholds of A1c (8.0%, 8.5%, 9.0%, and 9.5%).
  
  
  RESULTS
  The adjustment model had R2 = 8.3% with stable parameter estimates on thirty random 50% resamples. Adjustment for patient complexity resulted in the greatest rank differences in the best and worst performing deciles, with similar patterns across all tested thresholds.
  
  
  CONCLUSIONS
  Adjustment for complexity resulted in large differences in identified best and worst performers at all tested thresholds. Current performance measures of glycemic control may not be reliably identifying quality problems, and tying reimbursements to such measures may compromise the care of complex patients.
authors.affiliation: Deep South Center on Effectiveness at Birmingham VA Medical Center and University of Alabama at Birmingham, Birmingham, AL, USA. msafford@uab.edu
authors.forename: Monika M
authors.initials: MM
authors.lastname: Safford
authors.forename: Michael
authors.initials: M
authors.lastname: Brimacombe
authors.forename: Quanwu
authors.initials: Q
authors.lastname: Zhang
authors.forename: Mangala
authors.initials: M
authors.lastname: Rajan
authors.forename: Minge
authors.initials: M
authors.lastname: Xie
authors.forename: Wesley
authors.initials: W
authors.lastname: Thompson
authors.forename: John
authors.initials: J
authors.lastname: Kolassa
authors.forename: Miriam
authors.initials: M
authors.lastname: Maney
authors.forename: Leonard
authors.initials: L
authors.lastname: Pogach