Socioeconomic and Racial/Ethnic Differences in the Discussion of Cancer

Screening: “Between-” vs. “Within-” Physician Differences

Yuhua Bao, Ph.D.†,

Sarah Fox, Ed.D.†,

Jose Escarce, M.D., Ph.D. ‡

† Center for Community Partnerships in Health Promotion,

UCLA General Internal Medicine/Health Services Research

‡ UCLA GIM/HSR

Funded by the NIH EXPORT Center at UCLA/DREW (YB), NCI (SAF) and AHRQ (JE)

2

Socioeconomic and Racial/Ethnic Disparities in Cancer and Cancer Screening

Recent years saw steady decline in cancer death rates and improvement in cancer survival

However, disparities by patient socioeconomic status (SES) are substantial in Adherence with cancer screening guidelines Stage of diagnoses Mortality and survival

Differences by patient race/ethnicity are less consistent, but Mortality from all cancers is highest among Blacks

3

The Role of Physician-Patient Communication

Differential adherence to cancer screening is partly due to differences in access to care. However,

Disparities in cancer screening utilization exist even among people with a usual source of care

People of low-SES more likely to cite “I didn’t know I need it” and “Dr did not recommend it”

as barriers to cancer screening (Finney et al. 2003) Disparities in cancer screening communication may

have played a role

4

The “Within-” vs. “Between-” Physician Differences

Once patients get access to health care, treatment disparities arise because Patients of different SES or race/ethnicity are

treated differently by the same physicians

(“within-physician” differences),

AND / OR They are treated by a different group of physicians

(“between-physician” differences)

5

“Within-physician” Differences

6

Possible Mechanisms for“Within- Physician” Differences

Patient-level factors Low-SES and/or racial/ethnic minority patients are less

aware of the need for cancer screening (Finney et al. 2003) They are less assertive / proactive in clinical encounters

Physician-level factors Physicians may perceive them to be less interested (van

Ryn and Burke 2000) Physicians may have greater difficulties in assessing their

needs and preferences (Balsa and McGuire 2001; 2003) Patient-physician interaction

Patient preferences and physician attitudes and perceptions are reinforced (IOM 2002)

7

“Between-physician” Differences

Dr. A

Dr. B

8

Possible Mechanisms for “Between- Physician” Differences

Physicians serving disproportionately more minority or low-SES patients May be less well trained Are less likely to be board-certified (Bach et al. 2004) Are more likely to be foreign medical school graduates

(Bellochs and Carter 1990) May be less knowledgeable about national preventive care

guidelines (Ashford et al. 2000) They may also have less resources in the community such

as Specialty groups with cancer screening capabilities Institutional support for preventive care

Some of the “within-physician” differences may be reinforced to become practice patterns

9

Research Question

How much of the differences in cancer screening discussion were due to “within-” vs. “between-“

physician differences?

10

Data: the Communication in Medical Care (CMC) Studies

A research series that promotes physician-patient communication on important preventive care topics

Aimed at developing and testing a physician-patient communication model to change patient health behaviors

The second and third studies in the series (CMC2&3) are both randomized controlled community trials that Teach the model in a Continuing Medical Education (CME)

program Focused on cancer screening behaviors

11

Data: Patient and Physician Samples Physicians: office-based, primary care, practicing at least

50% of the time CMC2: Los Angeles County CMC3: all southern California except LA County

Patients: having seen and expect to see study physician regularly, speaking either English or Spanish CMC2: 50-80 CMC3: 65-79

Data pooled from CMC2&3 baseline Physicians: N=191 Patients: N=5978 On average, patients had seen their physicians for 5 years Number of patients per physician: mean=31, median=30,

range: [2, 83]

12

Outcomes of Interest: Cancer Screening Discussion

“Did Dr. ever talk to you

about …”

Rate of Discussion (%)

Fecal Occult Blood Test (FOBT) 36.8

Sigmoidoscopy 30.9

Mammogram (female only) 67.1

Prostate Antigen Test (PSA)

(male only; CMC2)

46.0

13

Statistical Strategies

Probit model of cancer screening discussion Two specifications for each cancer screening discussion

outcome Model 1: Patient characteristics only

to assess the “overall” differences

Model 2: Model 1 + Physician Fixed Effects Differences that remain reflect “within-physician” differences “Between-physician” differences=“Overall” – “Within”

We report probabilities of discussion for each racial/ethnic or SES

group compared to a reference group Bootstrapped standard errors (and p-values) to provide

statistical inferences

14

By Education: Discussion of FOBT

* p <0.05; ** p<0.01

Compared to college graduates

-0.13

-0.03

-0.09

-0.03-0.04

-0.02

-0.14

-0.12

-0.1

-0.08

-0.06

-0.04

-0.02

0

Diff

eren

ce in

FO

BT

Dis

s. R

ate

Lt high school High school Some college

"Within-" Differences "Between-" Differences

**

**

** **

*

15

By Education: Discussion of Mammogram

* p <0.05; ** p<0.01

Compared to college graduates

-0.071

-0.004

-0.028

-0.013

-0.037

-0.005

-0.08

-0.07

-0.06

-0.05

-0.04

-0.03

-0.02

-0.01

0

Diff

eren

ce in

Mam

mog

ram

Dis

s. R

ate

Lt high school High school Some college

"Within-" Differences "Between-" Differences*

16

By Education: Discussion of PSA

* p <0.05; ** p<0.01

Compared to college graduates

-0.192

-0.01

-0.144

0.026

-0.063

-0.012

-0.25

-0.2

-0.15

-0.1

-0.05

0

0.05

Diff

eren

ce in

PS

A D

iss.

Rat

e

Lt high school High school College graduates

"Within-" Differences "Between-" Differences

**

**

17

By Income: Discussion of FOBT

* p <0.05; ** p<0.01

Compared to annual income of $75+

-0.02

-0.06

-0.02

-0.04

0.02

-0.03

-0.07

-0.06

-0.05

-0.04

-0.03

-0.02

-0.01

0.00

0.01

0.02

0.03

Diff

eren

ce in

FO

BT

Dis

s. R

ate

Less than $15k $15k - $35k $35k - $75k

"Within-" Differences "Between-" Differences**

*

*

18

By Income: Discussion of Mammogram

* p <0.05; ** p<0.01

-0.001-0.007

0.013

-0.004

0.05

-0.003-0.01

0

0.01

0.02

0.03

0.04

0.05

0.06

Diff

eren

ce in

Mam

mog

ram

Dis

s. R

ate

Less than $15k $15k - $35k $35k - $75k

"Within-" Differences "Between-" Differences

Compared to annual income of $75+

19

By Income: Discussion of PSA

* p <0.05; ** p<0.01

-0.108

0.019

-0.021-0.028

0.023

-0.03

-0.12

-0.1

-0.08

-0.06

-0.04

-0.02

0

0.02

0.04

Dif

fere

nce

in

PS

A D

iss.

Rat

e

Less than $15k $15k - $35k $35k - $75k

"Within-" Differences "Between-" Differences

Compared to annual income of $75+

20

Summary of findings

Disparities by education Strong education gradient in the discussion of all three types of

cancer screening Most of the education differences arose within physicians

Disparities by income Less consistent across different screening methods, but Seemed to have arisen because of “between- physician”

differences Differences by race/ethnicity

Asian/white differences in the discussion of FOBT and PSA were mostly “within-physician” differences

Same physicians were much more likely to have discussed mammogram with black than white patients

21

Study Limitations

Patient self-report of clinical encounter experience may not be consistent with what really happened If low-SES patients tend to under-report physicians’ discussion

Both within- and between- differences by SES are biased up But hard to say how that might change the relative magnitude of

the two types of differences It depends on the distribution of low (vs. high) SES patients

across physicians

On the other hand, it is arguable that what patients recall is what matters

Small sample sizes for some racial/ethnic groups Findings regarding racial/ethnic differences should be

interpreted with caution

22

Implications

Patient education plays an important role in determining what happens in a clinical encounter Tailor patient informational materials to the needs of low-

education patients Raise the awareness of physicians about the challenges faced

by low-education patients

Physicians are not evenly distributed across communities of different levels of income Targeting physicians practicing in low-income communities may

be especially promising

Geographic accessibility of providers is important to low-income patients