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Original Investigation
February 18, 2019

Association of Primary Care Physician Supply With Population Mortality in the United States, 2005-2015

Author Affiliations
  • 1Department of Medicine, Stanford University, Stanford, California
  • 2Department of Health Research and Policy, Stanford University, Stanford, California
  • 3Center for Primary Care, Harvard Medical School, Boston, Massachusetts
  • 4Division of General Medicine and Clinical Epidemiology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill
  • 5American Board of Family Medicine Center for Professionalism and Value in Health Care, Lexington, Kentucky
  • 6Ariadne Labs, Brigham and Women’s Hospital, Harvard T.H. Chan School of Public Health, Boston, Massachusetts
  • 7Division of General Medicine, Brigham and Women’s Hospital, Boston, Massachusetts
  • 8Department of Health Care Policy, Harvard Medical School, Boston, Massachusetts
  • 9Division of General Medicine and Primary Care, Beth Israel Deaconess Medical Center, Boston, Massachusetts
JAMA Intern Med. 2019;179(4):506-514. doi:10.1001/jamainternmed.2018.7624
Key Points

Question  What is the association between primary care physician density and population-level mortality?

Findings  In this epidemiological study of US population data, every 10 additional primary care physicians per 100 000 population was associated with a 51.5-day increase in life expectancy. However, from 2005 to 2015, the density of primary care physicians decreased from 46.6 to 41.4 per 100 000 population.

Meaning  Greater primary care physician supply was associated with improved mortality, but per capita primary care physician supply decreased between 2005 and 2015.


Importance  Recent US health care reforms incentivize improved population health outcomes and primary care functions. It remains unclear how much improving primary care physician supply can improve population health, independent of other health care and socioeconomic factors.

Objectives  To identify primary care physician supply changes across US counties from 2005-2015 and associations between such changes and population mortality.

Design, Setting, and Participants  This epidemiological study evaluated US population data and individual-level claims data linked to mortality from 2005 to 2015 against changes in primary care and specialist physician supply from 2005 to 2015. Data from 3142 US counties, 7144 primary care service areas, and 306 hospital referral regions were used to investigate the association of primary care physician supply with changes in life expectancy and cause-specific mortality after adjustment for health care, demographic, socioeconomic, and behavioral covariates. Analysis was performed from March to July 2018.

Main Outcomes and Measures  Age-standardized life expectancy, cause-specific mortality, and restricted mean survival time.

Results  Primary care physician supply increased from 196 014 physicians in 2005 to 204 419 in 2015. Owing to disproportionate losses of primary care physicians in some counties and population increases, the mean (SD) density of primary care physicians relative to population size decreased from 46.6 per 100 000 population (95% CI, 0.0-114.6 per 100 000 population) to 41.4 per 100 000 population (95% CI, 0.0-108.6 per 100 000 population), with greater losses in rural areas. In adjusted mixed-effects regressions, every 10 additional primary care physicians per 100 000 population was associated with a 51.5-day increase in life expectancy (95% CI, 29.5-73.5 days; 0.2% increase), whereas an increase in 10 specialist physicians per 100 000 population corresponded to a 19.2-day increase (95% CI, 7.0-31.3 days). A total of 10 additional primary care physicians per 100 000 population was associated with reduced cardiovascular, cancer, and respiratory mortality by 0.9% to 1.4%. Analyses at different geographic levels, using instrumental variable regressions, or at the individual level found similar benefits associated with primary care supply.

Conclusions and Relevance  Greater primary care physician supply was associated with lower mortality, but per capita supply decreased between 2005 and 2015. Programs to explicitly direct more resources to primary care physician supply may be important for population health.

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    3 Comments for this article
    Healthcare Reform
    Paul Nelson, M.D., M.S. | Family Health Care, P.C. retired
    From an operational standpoint, the financing of post-graduate training of primary care physicians should be within the cross-hairs for immediate reform. Medicare distributes most of the funding for residency training after medical school. Traditionally, this funding has been distributed based on the research budget of the respective medical school. I know of no efforts to encourage a systematic connection between regional needs and the number of primary residency positions being funded by Medicare.

    Putting aside these issues, there is no nationally focused and coordinated strategy to assist each community identify and solve their own portion of
    our nation's problems with healthcare effectiveness and efficiency.  Paradigm paralysis is profoundly entrenched. Other than increasing annual health spending, ACA 2010 has done very little to improve our nation's health. A new federally chartered, semi-autonomous institution will be required.

    Modeled obliquely on the Cooperative Extension Service for Agriculture since 1914 and funded by Congress with a fixed budget of $1.00 per citizen annually, its mandate would require three goals within 10 years: slowly decrease health spending as a portion of our national GDP from 18% to 13%, decrease our nation's annual maternal mortality incidence by 70%, and achieve 100% state by state participation in the structural reforms for the financing of primary healthcare. I propose the new institution be known as: National Health, a sister institution to the Federal Reserve.
    Nurse practitioners will be included in future studies correlating mortality rates and availability of primary care providers
    Edward Volpintesta, BA,MD | BETHEL MEDICAL GROUP

    Although nurse practitioners were not included this study, they surely will be in future studies for they can provide many primary care services.1
    They are licensed to practice in many states to provide primary care independently or collaborating with doctors.
    The shortage of primary care doctors won’t improve soon because it takes about 11 years to train one.
    Nurse practitioners are a logical solution.
    Edward Volpintesta MD
    1. Basu S, Berkowitz SA, Phillips Rl, et al. Jama Intern Med Association of primary care physician supply with population mortality in the United States, 2005-2015 published online February 18, 2019.
    Mid-level practitioners questioned as relevant equivalents to MDs/DOs
    James Walker, MD | Corpus Christi Medical Associates, P.A.
    With an abundance of respect to the NPs and PAs I know personally and professionally, some of whom I have helped in training, I deeply disagree that there is a role for such practitioners as primary care physicians. Firstly, they are not trained to be autonomous care providers in the sense that physicians are, bearing this unique burden throughout their training in various manners. Secondly, the empirical difference in length of training cannot be ignored nor thought of reasonably as an equivalency with that of physicians. However, I personally am not opposed to the idea of an eventual equivalency between physicians and mid-level providers; but I prefer that we start with other specialties which are not so broad as primary care, requiring the depth and breadth of experience and expertise for competency. I suggest first we begin with neurosurgery allowing an equivalency of mid-level practitioners to practice independently or with minimal supervision; then cardiothoracic surgeons; then primary care. Also, any policy maker or rules maker creating the designation of equivalency between physician and non-physician practitioner should first sign a statement that they themselves will not discriminate under any circumstances for their own personal care or that of their family based solely on the initials after the name of the provider. This is not stated in hyperbole in order to be sarcastic, but rather to make a compassionate point about how far we are drifting off course in our approach to health care. We absolutely can train more physicians - if we but have the courage to insist upon it.
    CONFLICT OF INTEREST: Have plans to develop a primary care practice consulting company