The Usual Source of Care
and Delivery of Preventive
Services to Medicare
Beneficiaries
Hoangmai Pham, MD, MPH
Deborah Schrag, MD, MPH*
J. Lee Hargraves, PhD
Peter B Bach, MD, MAPP**
*Memorial Sloan Kettering Cancer Center
** Centers for Medicare and Medicaid Services
Academy Health, June 2005
Does quality vary with physician
characteristics?
 Quality of care is suboptimal – across
demographics, SES, conditions, communities
 Evidence suggesting the influence of:
• Physician sex, specialty, practice type for specific
services or conditions
 Definitively established associations can:
• Direct quality assurance, quality improvement efforts
• Affect patient or payer choice of physician
Study Objective
 Assess associations between physician and
practice characteristics, and the quality of
preventive care their patients receive
Physician
characteristics
Practice
characteristics
Preventive
services
Methods – Data sources
 2000-01 Community Tracking Study Physician Survey
• 12,406 respondents, 59% response rate
• Clinically active physicians, PCPs oversampled
• Nationally representative
• Demographics, care setting, attitudes, practice behavior
• Linked through performing UPINs, to
 Medicare beneficiaries they treated in 2001, as
captured by the 5% 2001 Carrier File
Methods – Populations
 Physicians:
• Assigning the usual source of care (USOC) physician
- Physician billing for the plurality of a beneficiary’s evaluation and
management visits
- Ties broken by comparing total amount of paid claims
• Limited to USOCs who were general internists or
family/general pracitioners also responding to the CTS
 Beneficiaries:
• 65 years or older as of January 1, 2001
• Clinically eligible for at least one of six preventive services
Methods – Independent variables
• Physician characteristics
- Medical school site, Specialty, Board certification,
Number of years in practice, Sex
• Practice setting characteristics
- Practice type, Urban vs. rural location
- % revenue from Medicare, Medicaid, managed care
- HIT to access treatment guidelines or to generate
reminders
Methods – Outcome variables
 Whether clinically eligible beneficiaries received
each preventive services once
• Diabetic care – Eye exams and Hemoglobin A1c testing
• Cancer screening – Mammography and
Colonoscopy/sigmoidoscopy
• Vaccinations – Influenza and Pneumococcal
Methods – Analysis
 Unit of analysis: Individual beneficiary
 Logistic regression, applied CTS survey weights
 Adjusted for
• All other independent variables
• Beneficiary age, sex, race, comorbidity score (Klabunde)
• Median income in beneficiary’s zip code
• % of county adult population with 12+ yrs education
• % of beneficiary’s visits with USOC physician
• Number of clinical radiologists per capita in MSA
Results – Physicians and Beneficiaries
Physicians
Beneficiaries
12,406 CTS
survey
respondents
1,599,101
beneficiaries in
5% Carrier File
5,453 (50%) non-pediatricians
served USOC to patients 65
years or older
31,219 (3%) 65 years or
older had a CTS physician as
their usual source of care
3,660 (22%) primary
care physicians
served as a usual
source of care
Assignment
24,581 (2%) had a
CTS primary care
physician as their
usual source of care
• 5,914 diabetics
eligible for eye
exams and HbA1c
• 6,928 women for
mammograms
• 17,525 eligible for
colon cancer
screening
• 24,581 eligible for
vaccinations
Results – Receipt of services
Eye
Exams
Mammograms
Colon cancer
screening
Influenza
vaccination
Pneumococcal
vaccination
HbA1c
Expected
proportion
100%
100%
100%
10%, 20%
100%
10%
Observed
proportion
47.9
55.9
46.7
9.0
46.5
8.0
Proportion in
lowest
income tercile
44.9
50.9
39.8
8.0
41.5
7.3
Proportion in
highest
income tercile
53.2
59.5
50.8
10.3
50.8
8.7
Results – Physician characteristics and Proportion
of beneficiaries receiving preventive services
Diabetic
Eye Exam
HbA1c
Mammogram
Colon
cancer
screening
General IM
50.0
56.9
50.5
7.8
46.7
8.5
FP/GP
44.9*
54.5
42.4***
9.9***
46.4
7.4*
Certified
48.7
57.1
48.5
9.5
47.4
8.3
Not
certified
43.4
48.8*
36.5**
6.5*
41.7*
6.5**
N Amer
med grad
49.0
56.8
48.2
9.3
47.9
8.4
43.0**
52.3
39.7**
7.7*
40.0***
6.3**
Other FMG
*p<0.05, **p<0.01, ***p<0.001
Influenza
vaccination
Pneumococcal
vaccination
Results – Practice characteristics and
Proportion of beneficiaries receiving services
Diabetic
Eye Exam
HbA1c
Mammogram
Colon
cancer
screening
Solo/2
46.9*
52.3***
42.5***
8.4**
44.6**
7.0**
Small group
53.4
68.6
49.2
9.3
48.1
9.1
Med/large group
46.5
70.1
60.5
11.4
52.6
8.6
Other practice
45.1
44.0
45.6
8.8
45.8
8.7
Lowest Medicaid
tercile
48.9
61.2
52.1
10.0
50.2
8.2
Middle Medicaid
tercile
49.2
52.0**
43.3***
7.8***
44.4**
6.8***
Highest
Medicaid tercile
43.0*
48.4***
38.9***
8.5
39.2***
6.4***
Have HIT
49.5
57.0
48.3
5.8
47.0
8.6
45.4**
54.6
46.0
5.9
46.0
7.2**
No HIT
*p<0.05, **p<0.01, ***p<0.001
Influenza
vaccination
Pneumococcal
vaccination
Results – Physician characteristics and
delivery of services, adjusted OR’s (95% CI)
Diabetic Eye
Exam
HbA1c
Mammogram
Colon cancer
screening
Influenza
vaccination
Pneumococcal
vaccination
Female
1.19
(0.93-1.51)
0.96
(0.73-1.28)
1.33
(1.05-1.68)*
0.90
(0.74-1.09
0.82
(0.72-0.93)**
0.98
(0.83-1.17)
FP/GP
0.81
(0.67-0.97)*
1.11
(0.90-1.37)
0.83
(0.72-0.97)*
0.86
(0.75-0.99)**
1.08
(0.95-1.21)
0.95
(0.82-1.10)
Board
certified
1.12
(0.90-1.40)
1.22
(0.89-1.68)
1.34
(1.04-1.71)*
1.27
(1.04-1.57)*
1.08
(0.92-1.26)
1.06
(0.86-1.32)
Other
FMG
0.82
(0.68-0.99)*
0.91
(0.70-1.18)
0.78
(0.63-0.98)*
0.92
(0.76-1.12)
0.82
(0.71-0.94)**
0.74
(0.59-0.93)*
Results – Practice characteristics and delivery
of services, adjusted OR’s (95% CI)
Mammogram
Colon
cancer
screening
Influenza
vaccination
Pneumococcal
vaccination
1.90
(1.45-2.48)**
1.13
(0.89-1.44)
0.97
(0.78-1.22)
1.01
(0.89-1.15)
1.19
(0.99-1.44)
0.81
(0.59-1.10)
1.91
(1.40-2.60)**
1.40
(1.10-1.77)**
1.12
(0.90-1.38)
1.22
(0.98-1.50)
1.16
(0.95-1.42)
Other
practice
0.84
(0.73-0.96)*
0.68
(0.51-0.90)*
1.03
(0.86-1.23)
0.91
(0.75-1.10)
1.03
(0.90-1.18)
1.21
(1.02-1.45)*
Middle
Medicaid
tercile
1.12
(0.97-1.29)
0.74
(0.60-0.92)**
0.81
(0.71-0.92)**
0.87
(0.75-1.00)**
0.85
(0.75-0.95)**
0.76
(0.65-0.89)***
Highest
Medicaid
tercile
1.04
(0.83-1.29)
0.73
(0.57-0.95)**
0.76
(0.62-0.94)**
1.09
(0.91-1.31)
0.77
(0.68-0.87)***
0.73
(0.60-0.89)**
1.21
(1.08-1.35)***
1.13
(0.97-1.33)
1.07
(0.96-1.20)
0.96
(0.84-1.09)
1.02
(0.93-1.13)
1.21
(1.06-1.38)**
Diabetic Eye
Exam
HbA1c
Small
group
1.12
(0.84-1.49)
Med/large
group
Have HIT
Summary
 Quality of preventive care is suboptimal
across the board
 Physician and practice characteristics
associated with delivery of preventive
services
• Strongest associations were with practice level
factors – revenue from Medicaid and practice
type, less so availability of HIT
• Medical school site, specialty, and board
certification
Conclusions and Implications
 Physician and practice factors account for a
meaningful degree of the variation in quality of
preventive care
 Practice level factors appear particularly
influential and should be considered, in addition
to individual physician factors, in designing
quality improvement interventions
Results – Physician characteristics and Proportion
of beneficiaries receiving preventive services
Diabetic
Eye Exam
HbA1c
Mammogram
Colon
cancer
screening
Male
47.7
56.6
46.1
9.1
47.6
7.9
Female
49.0
51.9
50.0*
8.7
43.0***
8.0
General IM
50.0
56.9
50.5
7.8
46.7
8.5
FP/GP
44.9*
54.5
42.4***
9.9***
46.4
7.4*
Certified
48.7
57.1
48.5
9.5
47.4
8.3
Not
certified
43.4
48.8*
36.5**
6.5*
41.7*
6.5**
N Amer
med grad
49.0
56.8
48.2
9.3
47.9
8.4
43.0**
52.3
39.7**
7.7*
40.0***
6.3**
Other FMG
*p<0.05, **p<0.01, ***p<0.001
Influenza
vaccination
Pneumococcal
vaccination