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Access to more primary care physicians associated with lower mortality

There was lower population-level mortality in counties of the United States where the number of primary care physicians increased, according to a study published in JAMA Internal Medicine.

“Prior studies had found broad correlations between the number of primary care physicians in a state and the state’s mortality rates,” Sanjay Basu, MD, PhD, assistant professor of medicine at the Stanford School of Medicine, told Healio Primary Care Today. “This study dissected the relationship down to a small level (counties), and examined the mechanisms of the association, compared the relationship to specialists, and tried to understand whether there was a causal link between primary care and mortality by identifying how people who moved between areas or physicians attracted to an area by an educational loan program for primary care physicians affected death rates and life expectancy.”

To determine the association between population-level physician supply and population-level mortality, researchers conducted an epidemiological study using data from 3,142 U.S. counties, 7,144 primary care service areas and 306 hospital referral regions. U.S. population data and individual-level claims data linked to mortality were investigated against changes in primary care and specialist physician supply from 2005 to 2015.

The primary outcome of the study was life expectancy. Secondary outcomes included cause-specific mortality and restricted mean survival time.

During the study period, researchers found that primary care physician supply increased from 196,014 physicians in 2005 to 204,419 in 2015.

However, in some counties, researchers observed disproportionate losses of primary care physicians at the same time as population increases, causing the mean density of primary care physicians relative to population size to decrease from 46.6 per 100,000 population (95% CI, 0-114.6) to 41.4 per 100,000 population (95% CI, 0-108.6). Researchers also noted that greater losses occurred in rural areas.

After adjusting for health care, demographic, socioeconomic and behavioral covariates, researchers found that 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; 0.2% increase) and that an increase in 10 specialist physicians per 100,000 population was associated with a 19.2 day increase (95% CI, 7.0-31.3).

Furthermore, an additional 10 primary care physicians per 100,000 population corresponded to reduced cardiovascular, cancer and respiratory mortality by 0.9% to 1.4%.

According to Basu, a greater supply of primary care physicians appeared to increase the chances that a person would be treated for CVD risk factors like high BP or high cholesterol or that physicians would identify major cancers — like breast or colon cancer — early.

“While primary care physician availability relates to important goals like longer life and lower death rates, the number of primary care doctors is dwindling,” Basu said. “We need to determine how to attract great medical students into the primary care field.”

In a related commentary, Sondra Zabar, MD, Andrew Wallach, MD, and Adina Kalet, MD, MPH, all of the division of general internal medicine and clinical innovation in the department of medicine at New York University School of Medicine, wrote that the findings are consistent with current data showing access to primary care is associated with better health outcomes.

“Unfortunately, their study also confirms that the primary care workforce is maldistributed, with many rural communities having no primary care physicians,” they wrote. “To increase access to primary care, especially in underserved areas, we must align incentives to attract individuals into primary care practice, innovate primary care training, and greatly improve the primary care practice model. Physician payment reform is a key to making all of this happen.” – by Melissa J. Webb

For more information:

Sanjay Basu, MD, PhD, can be reached at basus@stanford.edu.

Disclosures: Basu reports no relevant financial disclosures. Please see the study for all other authors’ relevant financial disclosures.