Physician-Level Performance and
Racial Disparities in Diabetes Care
Thomas D. Sequist, MD MPH
Garret M. Fitzmaurice, ScD
Richard Marshall, MD
Shimon Shaykevich, MS
Dana G. Safran, ScD
John Z. Ayanian, MD MPP
Background
• Racial disparities in diabetes care
– Impact of quality improvement
– Importance of outcomes measures
• Role of health care source
– Health plan effects
– Individual physician contributions
Harvard Vanguard Medical Associates
Division of General Medicine, Brigham and Women’s Hospital
Department of Health Care Policy, Harvard Medical School
Study Questions
• What contributes to observed racial disparities?
– Patient sociodemographic features
– Within versus between physician effects
• What physician panel features predict equal care?
– Diversity of patient panel
– Overall performance
Methods – Study Population
• Patient eligibility
– White or Black race
– Age ≥ 18 years
– Primary care visit during 2003-2005
• Physician eligibility
– At least 5 white patients AND 5 black patients
Methods – Study Site
• Harvard Vanguard Medical Associates
• Integrated multispecialty group practice
– 14 health centers in eastern MA
– Common electronic medical record
• Diabetes disease registry
– Problem list diagnosis of diabetes, AND
– Fasting glucose > 126 mg/dL, OR
Random glucose > 200 mg/dL, OR
Resulted Hemoglobin A1c
Methods – Quality Measures
• Collected from coded fields in electronic
medical record
• Diabetes outcomes measures
– HbA1c < 7%
– LDL cholesterol < 100 mg/dL
– BP < 130/80
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Methods – Analysis
Patient Characteristics
• Contributions to racial disparities
– Hierarchical linear regression models
– Adjust for patient characteristics
– Random effects for physician and health center
White
(n = 3,810)
Black
(n = 2,181)
p
value
58.5
54.1
<0.001
Mean age, years
Male, %
Median income, $
• Physician panel-level correlates
Insurance, %
Commercial
Medicare
Medicaid
Uninsured
– Number of black patients within patient panel
– Adjusted correlation between magnitude of racial
disparity and overall performance
Physician Characteristics (n=88)
57
42
<0.001
54,829
38,581
<0.001
62
34
3
1
73
17
7
3
<0.001
Population Level Disparities in Care
100
• Median number of diabetic patients per physician
White
% acheiving goal
– White: 38 (IQR 21 to 60, max 137)
– Black: 14 (IQR 9 to 33, max 116)
• 50% male
Black
80
60
48
41
40
32
38
36
29
20
• Mean age = 48.2 years
0
HbA1c < 7
LDL < 100
BP < 130/80
• Mean years of employment = 12.0 years
All p<0.001
Patient and Physician Effects
Base Model*
White-Black
(%)
Patient Model†
White-Black
(%)
Patient and Physician Effects
Physician Model§
White-Black
(%)
Base Model*
White-Black
(%)
Patient Model†
White-Black
(%)
HbA1c < 7%
9.5
HbA1c < 7%
9.5
8.4
LDL < 100 mg/dL
10.3
LDL < 100 mg/dL
10.3
7.2
BP < 130/80 mmHg
6.5
BP < 130/80 mmHg
6.5
8.0
Physician Model§
White-Black
(%)
* No adjustment
* No adjustment
†
Adjusted for patient age, sex, income, insurance status
†
Adjusted for patient age, sex, income, insurance status
§
Adjusted for patient characteristics and random effects of physician and center
§
Adjusted for patient characteristics and random effects of physician and center
2
Patient and Physician Effects
Panel Diversity and Disparities in HbA1c Control
Patient Model†
White-Black
(%)
Physician Model§
White-Black
(%)
HbA1c < 7%
9.5
8.4
8.6
LDL < 100 mg/dL
10.3
7.2
6.4
BP < 130/80 mmHg
6.5
8.0
8.7
* No adjustment
†
Adjusted for patient age, sex, income, insurance status
§
Adjusted for patient characteristics and random effects of physician and center
20
Adjusted Black-White Difference (%)
Base Model*
White-Black
(%)
IQR = - 6.6% to - 10.4%
10
5
0
0
20
40
60
80
100
120
140
-5
-10
-15
P=0.26
-20
Panel Diversity and Disparities in LDL Control
Number of black patients
Panel Diversity and Disparities in BP Control
15
Median = - 6.4%
15
IQR = -3.3% to -9.5%
10
5
0
0
20
40
60
80
100
120
140
-5
-10
-15
P=0.70
-20
Number of black patients
Adjusted Black-White Difference (%)
20
Adjsuted Black-White Difference (%)
Median = - 8.4%
15
Median = - 8.9%
10
IQR = - 7.9% to - 9.8%
5
0
0
20
40
60
80
100
120
140
-5
-10
P=0.83
-15
Number of black patients
Physician Overall Performance and Disparities
Adjusted
Correlation
p
value
HbA1c < 7%
-0.80
0.20
LDL cholesterol < 100 mg/dL
0.01
0.98
BP < 130/80 mmHg
0.09
0.92
Limitations
• Single multispecialty practice group
• Advanced disease registry with central
management program
• No inclusion of non-black minority
groups
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Discussion
• Racial disparities mainly related to:
– Patient characteristics
– Within-physician differences
• No relation to panel diversity or overall
quality at the individual physician level
Implications
• Common quality improvement methods
of limited utility
– Targeting outlier physicians
– Shifting care to high performing clinicians
• Improving equity will require systemic
efforts
Funding Acknowledgement
Finding Answers: Disparities Research for Change
A National Program of the
Robert Wood Johnson Foundation
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