People in counties with too few primary care physicians live at least a year-and-a-half less on average than peers in better-served regions, according to a study led by Harvard Medical School researchers who indicate that the government may be undercounting areas in need.

In an article published March 22 in the Annals of Internal Medicine, the team of researchers projected that getting counties with fewer than one primary care physician per 1,500 residents above that threshold could lift life expectancy by about 56 days on average. It could also prevent over 7,000 deaths per year across those counties  — a significant boon to underserved communities.

The magnitude of those benefits means the official threshold for defining counties in need — set at one primary care physician per 3,500 residents by the U.S. Health Resources and Services Administration — may miss places that would see the biggest boost from having more doctors, according to author Sanjay Basu.

"A few years ago, the Health Resources and Services Administration asked an independent panel of experts to determine how to determine what threshold of physician availability should define a county with a shortage, to help areas with a shortage get additional resources like loan repayment programs for physicians located there," he told The Academic Times.

The HRSA ultimately rejected the panel's recommendation to expand its definition of a low-availability area, he added, restricting its official, nationwide tally of "shortage counties."

"Our findings suggest the panel's recommendations would help explain a lot of disparities within the US and potentially aid in improving those disparities," he added.

To understand where shortages of primary care doctors were leading to the starkest disparities in health outcomes, the researchers analyzed 2017 HRSA data from a total of 3,104 counties, of which 1,218 faced primary care shortages according to the agency's definition. 

They defined primary care physicians as non-federally employed doctors younger than 75 who worked mainly in general practice, family medicine, general internal medicine or general pediatrics. The definition excluded hospital residents, or doctors in training.

Using a series of models to explore the effects of greater primary care physician density on life expectancy and mortality, the researchers uncovered a substantial divide between counties above and below the shortage thresholds.

People who lived in counties with fewer than one primary care physician per 3,500 people had an average life expectancy that was 311 days shorter than people in counties above that threshold, the researchers found, a gulf that grew to 629 days when they compared counties above and below the ratio of one primary care physician per 1,500 people.

By ensuring that shortage counties have one primary care physician per 3,500 population, residents of those counties would see their life expectancy increase by around 22.4 days on average, according to the analysis, an effort that would require adding an extra 17,651 primary care physicians in total to those areas. At that density, the counties could expect to avert 230 total deaths per year.

But increasing density to one primary care physician per 1,500 people in counties below this threshold would increase residents' life expectancy by an average of 56.3 days. That would require deploying a total 95,754 additional primary care physicians across the country, they noted, but would also result in 7,272 averted deaths per year.

While their findings make clear the positive impacts of getting more doctors into areas where they're currently stretched thin, Basu said, it isn't likely these areas will have their shortages addressed anytime soon.

That's because a variety of financial and related professional considerations tend to keep many medical school graduates from choosing primary care or working in places they may be needed the most.

"Graduates of the nation's top medical schools disproportionately choose 'lifestyle' specialties like dermatology and ophthalmology, in response to financial incentives," he said. "Meanwhile, primary care physicians report disproportionately low pay and increased burnout given their workloads."

Besides enticing primary care physicians to in-need areas by offering loan repayment, Basu said, the health care industry as a whole should also structure compensation in a way that puts a premium on patient outcomes.

"We need to revise payments from incentivizing the conduct of procedures or tests, to actually paying for performance — keeping people healthier should be incentivized," he said.

The article "Estimated Effect on Life Expectancy of Alleviating Primary Care Shortages in the United States," published March 22 in the Annals of Internal Medicine, was authored by Sanjay Basu, Harvard Medical School, Brigham and Women's Hospital, Harvard T.H. Chan School of Public Health, Collective Health, Imperial College London; Russell S. Phillips and Bruce E. Landon, Harvard Medical School, Beth Israel Deaconess Medical Center; Seth A. Berkowitz, Harvard Medical School, UNC School of Medicine; Asaf Bitton, Harvard Medical School, Brigham and Women's Hospital, Harvard T.H. Chan School of Public Health; Robert L. Phillips, Harvard Medical School, American Board of Family Medicine Center for Professionalism and Value in Health Care.