April 2001

Grant Results

SUMMARY

From 1992 to 1995, researchers at the University of California, San Francisco, studied access to primary care in selected urban California communities. The research was designed to assess whether hospitalization rates for certain chronic conditions typically managed by timely outpatient care are valid and useful measures of community access to care.

Using hospital discharge and census data, the researchers calculated hospitalization rates for five "ambulatory care sensitive" (ACS) conditions — asthma, hypertension, congestive heart failure, chronic obstructive pulmonary disease and diabetes — among 250 zip code clusters in California.

Key Findings
Among the investigators' key findings:

  • Communities where people perceive their access to care as the lowest have the highest rates of hospitalization for ambulatory care sensitive conditions.
  • Hospitalizations for ambulatory care sensitive conditions were higher in communities with greater proportions of uninsured and Medicaid patients, and higher in areas where greater proportions of residents said they had no regular place to obtain health care.
  • Variations in physician practice styles or in patients' propensity to seek care for medical symptoms could not explain variations in hospitalization rates for ambulatory care sensitive conditions.

Funding
The Robert Wood Johnson Foundation (RWJF) supported this project through two grants totaling $680,341.

 See Grant Detail & Contact Information
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THE PROBLEM

When this study was funded, access to health care had been previously measured largely through sample surveys, which were mostly national in scope. Such surveys were inadequate for addressing community-level barriers to care because they generally contained too few observations in any given community. The high cost of these surveys also made it difficult for a community to conduct such surveys themselves.

To overcome these limitations, investigators developed a promising method for measuring access to care at the community level. Called small-area analysis, it relies on readily available computerized hospital discharge data to provide information on utilization, illness, and death, frequently by zip code.

In a RWJF-supported study in New York City (see Grant Results on ID# 016739), for example, investigators with the United Hospital Fund of New York used small-area analysis to compare income levels and hospitalization rates for ambulatory care sensitive (ACS) conditions — including asthma, congestive heart failure, and diabetes — which are potentially responsive to timely and effective outpatient management. Hospitalization rates for these conditions were highest among low-income communities, the New York researchers found.

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THE PROJECT

The research supported under two grants from RWJF was designed to assess whether hospitalization rates for ACS conditions are a valid and useful measure of community access to care by enabling researchers at the University of California, San Francisco, to study access to primary care in selected urban California communities.

The investigators were encouraged by RWJF to collaborate with the United Hospital Fund of New York team. Under the first grant (ID# 018869), researchers sought to directly measure the association between a community's access to primary care and its hospitalization rates for ACS conditions. Using 1990 California hospital discharge and US Census data, they calculated the hospitalization rates for five ACS conditions — asthma, hypertension, congestive heart failure, chronic obstructive pulmonary disease, and diabetes — for the 250 zip code clusters that comprise urban California communities.

Investigators measured three additional factors that could affect the variation in hospitalization rates for ACS conditions among different communities:

  • The health-seeking behavior of individuals was explored in a survey of a random sample of 6,674 community residents drawn from 41 of the 250 zip code clusters. Questions probed individuals' propensity to seek care for ACS symptoms, their health insurance status, and their perceived access to care.
  • The prevalence of ACS conditions in the community was estimated from the survey of community residents and 1990 National Health Interview Survey (NHIS) data. (The NHIS, an activity of the federal National Center for Health Statistics, has annually since 1957 collected information on health status, access to health care, and insurance, health services utilization and other topics.)
  • Variations in physicians' practice patterns were explored in a survey of more than 723 primary care and emergency physicians in the 41 zip code clusters. This survey was supported by the second grant, ID# 022907. Physicians were presented with case descriptions of varying severity and rated how likely they were to hospitalize the individuals described.

An expert panel provided advice and feedback throughout the project. (For a roster of members, see the Appendix.) The principal investigator received a $24,498 grant from the California Policy Seminar for the current project. The California Policy Seminar applies research done within the University of California system to the analysis, development and implementation of state policy.

In addition, the principal investigator was co-investigator on a $3.9 million Agency for Health Care Policy and Research grant, from which he used $20,000 a year for this research.

Additional support also came through the principal investigator's participation in RWJF's Generalist Physician Faculty Scholars program, which offers four-year career development awards to outstanding junior faculty in medical school departments of family practice, general internal medicine, and general pediatrics; he used this support to hire an epidemiologist to assist in the data analysis.

Finally, some data analyses for this project were supported with resources from a separate $649,000 RWJF grant (see Grant Results on ID# 017488) to the United Hospital Fund exploring variations in diagnosis rates for ambulatory care sensitive conditions.

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FINDINGS

The investigators reported the following findings in an article in the July 26, 1995, issue of JAMA.

  • Hospitalization rates for the five ACS conditions varied inversely with residents' ratings of their access to care. In communities with the highest hospitalization rates for ACS conditions, residents rated their access to care the lowest. The strong positive association between hospitalization rates for ACS conditions and perceived access to care suggests that these rates can serve as a valid measure of access to care, the investigators stated.
  • Hospitalizations for ACS conditions were higher in communities with greater proportions of uninsured and Medicaid patients, and higher in areas where greater proportions of residents said they had no regular place to obtain health care.
  • Variations in physician practice styles or in patients' propensity to seek care for medical symptoms could not explain variations in hospitalization rates for ACS conditions. The use of guidelines or incentives to reduce physician discretion or uncertainty about hospitalizing these patients is unlikely to be effective, the investigators wrote.
  • The relationship between perceived access to care and hospitalization rates for ACS conditions persists even after controlling for differences in demographics, income, the prevalence of ACS conditions, the propensity to seek care, and physician practice styles.

Limitations

  • The research design was cross-sectional, limiting the ability to establish a clear causal link between perceived access to care and preventable hospitalization rates for ACS conditions. Only with a longitudinal study following patients with ACS conditions over time would the researchers be able to see if improved access to care results in lower hospitalization rates for these conditions.

Communications

The researchers published their findings in several journals, including NEJM, Health Affairs, and Journal of General Internal Medicine; and presented their work at national meetings. (See the Bibliography for details.) The main article resulting from the project, "Preventable Hospitalizations and Access to Health Care," was published in JAMA and was selected as "article of the year" by the Association for Health Services Research. The research also drew coverage by National Public Radio, The New York Times, and ABC News's "Nightline."

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AFTER THE GRANT

The principal investigator and his colleagues currently are conducting a longitudinal analysis of how managed care penetration in the community affects hospitalization rates for ACS conditions.

Many local and state health departments in the United States, as well as health departments in other countries, have adopted the use of ACS measures as a means to monitor access to primary care.

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GRANT DETAILS & CONTACT INFORMATION

Project

Study of Barriers to Primary Care in California

Grantee

University of California, San Francisco (San Francisco,  CA)

  • Amount: $ 649,341
    Dates: March 1992 to April 1995
    ID#:  018869

  • Amount: $ 31,000
    Dates: October 1993 to March 1994
    ID#:  022907

Contact

Andrew B. Bindman, M.D.
(415) 206-6095
bindman@itsa.ucsf.edu

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APPENDICES


Appendix 1

(Current as of the time of the grant; provided by the grantee organization; not verified by RWJF.)

Advisory Board

John Billings, J.D.
Professor
New York University

Robert F. Wagner Graduate School of Public Service
New York, N.Y.

E. Richard Brown, Ph.D.
University of California, Los Angeles
Los Angeles, Calif.

Philip Lee, M.D.
Director
Institute for Health Policy Studies
University of California, San Francisco
San Francisco, Calif.

Paul Newacheck, Dr.P.H.
University of California, San Francisco
San Francisco, Calif.

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BIBLIOGRAPHY

(Current as of date of this report; as provided by grantee organization; not verified by RWJF; items not available from RWJF.)

Articles

Bindman AB, Grumback K, Osmond D, Komaromy MS, Vranizan K, Lurie N, Billings J, and Stewart A. "Preventable Hospitalizations and Access to Health Care." Journal of the American Medical Association, 274(4): 305–311, 1995. Abstract available online.

Bindman AB, Grumbach K, Osmond D, Vranizan K, and Stewart AL. "Primary Care and Receipt of Preventive Services." Journal of General Internal Medicine, 11(5): 269–276, 1996. Abstract available online.

Grumbach K, Becker S, Osborn E, and Bindman AB. "The Challenge of Defining and Counting Generalist Physicians: An Analysis of Physician Masterfile Data." American Journal of Public Health, 85(10): 1402–1407, 1995. Abstract available online.

Grumbach K, Vranizan K, and Bindman AB. "Physician Supply and Access to Care in Urban Communities." Health Affairs, 16(1): 71–86, 1997. Abstract available online.

Komaromy M, Lurie N, and Bindman AB. "California Physicians' Willingness to Care for the Poor." Western Journal of Medicine, 162(2): 127–132, 1995. Abstract available online.

Komaromy M, Grumbach K, Drake M, Vranizan K, Lurie N, Keane D, and Bindman AB. "The Role of Black and Hispanic Physicians in Providing Health Care for Underserved Populations." New England Journal of Medicine, 334(20): 1305–1310, 1996. Abstract available online.

Komaromy M, Lurie N, Osmond D, Vranizan K, Keane D, and Bindman AB. "Physician Practice Style and Hospitalization Rates for Chronic Medical Conditions." Medical Care, 34(6): 594–609, 1996. Abstract available online.

Osmond DH, Vranizan K, Schillinger D, Stewart AL, and Bindman AB. "Measuring the Need for Medical Care in an Ethnically Diverse Population." Health Services Research, 31(5): 551–571, 1996. Abstract available online.

Stewart AL, Grumbach K, Osmond D, Vranizan K, Komaromy M, and Bindman AB. "Primary Care and Patient Perceptions of Access to Care." Journal of Family Practice, 44(2): 177–185, 1997. Abstract available online.

Presentations and Testimony

Andrew B. Bindman, "Measuring Primary Care Effectiveness with Hospital Admission Rates," at the American Public Health Association annual meeting, 1993, Washington, D.C.

Andrew B. Bindman, "Health Access and Preventable Hospitalization Rates," at the Society of General Internal Medicine annual meeting, April 1994, Washington, D.C.

Andrew B. Bindman, "Using Avoidable Hospitalizations to Measure Access to Care," at the Association for Health Services Research annual meeting, June 1994, San Diego, Calif.

Print Coverage

Article in The New York Times, date unknown.

Radio Coverage

Coverage on National Public Radio, date unknown.

Television Coverage

Coverage on ABC News's "Dateline," date unknown.

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Report prepared by: Mike Meagher
Reviewed by: Richard Camer
Reviewed by: Janet Heroux
Program Officer: Joel Cantor
Program Officer: James Knickman

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