Assessing quality of diabetes care by measuring longitudinal changes in hemoglobin A1c in the Veterans Health Administration.
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.
Thompson
Wes
W
Deep South Center on Effectiveness at the Birmingham VA Medical Center and the University of Alabama, 35294, USA.
Wang
Hongwei
H
Xie
Minge
M
Kolassa
John
J
Rajan
Mangala
M
Tseng
Chin-Lin
CL
Crystal
Stephen
S
Zhang
Quanwu
Q
Vardi
Yehuda
Y
Pogach
Leonard
L
Safford
Monika M
MM
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*
D006442:Glycated Hemoglobin