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Primary Care’s Impact on Outcomes

Expanding the primary care workforce is viewed as a solution to the health needs of Americans. However, current research suggests that more nuanced metrics are necessary to reveal the ideal physician-to-population ratio.

While expanding the primary care physician (PCP) workforce is generally acknowledged as one solution for our nation’s health care needs, prior research has shown a lack of consistency between numbers of PCPs per population and actual patient outcomes.  The authors of this study therefore sought new methods of measurement of the workforce in order to strengthen the original claim; their hypothesis was that high levels of PCPs are associated with better patient outcomes, namely, lower mortality, fewer preventable hospitalizations, and lower spending.

Two measures of PCPs were used: (1) specific numbers of PCPs based on data in the American Medical Association Physician Masterfile and (2) estimated ambulatory clinical full-time equivalents (FTEs) derived from Medicare office- and clinic-based claims of primary care physicians. Using a patient population of fee-for-service Medicare beneficiaries, the PCP workforce was divided into geographic service ares that reflected the use of primary care services. These Primary Care Service Areas (PCSAs) were categorized by quintiles for each of the two PCP measures.

After adjustments for patient and area covariates, beneficiaries residing in PCSAs with highest numbers of PCPs had 6 percent lower rates of preventable hospitalizations in comparison to those in PCSAs with the lowest numbers of PCPs.  Stronger associations were shown with the physician FTE measurement.  Beneficiaries residing in PCSAs with highest primary care FTEs had 5 percent lower mortality and 9 percent fewer preventable hospitalizations, but 1 percent higher total Medicare program spending, than those beneficiaries residing in PCSAs with the lowest number of primary care FTEs.

It is worth noting that several inconsistencies were shown between the two measures.  Concerning patient characteristics, beneficiaries residing in PCSAs with lower numbers of PCPs were more likely to have had any or multiple chronic conditions, while beneficiaries residing in PCSAs with higher levels of primary care FTEs had fewer chronic conditions.  Concerning unadjusted patient outcomes, higher numbers of PCPs correlated with lower spending, while higher levels of primary care FTEs correlated with higher spending.  The authors highlighted the fact that the data in the AMA Masterfile does not accurately reflect those PCPs treating this specific Medicare study populations, therefore affecting the more traditional measurement of PCPs per population.

Overall, the data suggests that the benefits of the primary care workforce are from the amount of ambulatory clinical care provided, rather than the number of PCPs locally available.  More physicians trained in primary care practicing in an area does not ensure substantially lower mortality rates, fewer hospitalizations or lower costs.


Though there is some lack of consistency throughout this study, there is strength in the idea that our general approach to measuring “primary care” should be readdressed.  Yes, it is necessary to have further research using different PCP per population metrics, and on younger populations and private health plan consumers.  However such research should focus on the actual impact of having a primary care workforce – namely, the actual primary care activity provided – as opposed to the number of PCPs available.

This study acknowledges a larger question: who provides primary care?  It is difficult to narrow down to numbers and specific individuals – primary care services are often provided in emergency rooms, specialty offices, and inpatient hospital units, being that many patients do not have an acknowledged PCP to address basic outpatient needs, counseling, and education.  Increasing the numbers of PCPs would help this problem, but the distribution of PCPs to this specific underserved population and the effective delivery of primary care services are not guaranteed.  In addition to increasing incentives to enter primary care fields, policy makers should provide practice-level assistance (e.g. financial support through improved reimbursement, ancillary staff support, electronic medical records) in order to assure that PCPs are providing care how and where it is needed.

Chang C, et al. “Primary Care Physician Workforce and Medicare Beneficiaries’ Health Outcomes.”  JAMA.  2011; 305(20): 2096-2105.


Kameron L. Matthews, MD, Esq.





Kameron Matthews, MD, JD, FAAFP
About Kameron Matthews, MD, JD, FAAFP

Lead Analyst – Access to Care Kameron Matthews MD, JD is a board-certified family physician and currently serves as Deputy Executive Director of Provider Relations and Services in the Office of Community Care at the Veterans Health Administration in Washington, DC. She earned her medical degree from Johns Hopkins University and her law degree from the University of Chicago. Contact: Facebook | Twitter | More Posts