This study used U.S. population data to identify changes in the supply of primary care physicians across counties from 2005 to 2015 and the association with life expectancy and other outcomes.
A greater supply of primary care physicians was associated with better life expectancy but the per capita supply of primary care physicians across counties decreased, mostly because of disproportionate losses in some counties and population increases in general. More specifically, the total number of primary care physicians in the United States increased (196,014 in 2005 to 204,419 in 2015) but distribution across counties changed with the average supply of primary care physicians decreasing from about 46 to 41 per 100,000 population, with greater declines in rural areas. However, every 10 additional primary care physicians per 100,000 population was associated with a 51-day increase in life expectancy, after accounting for health care, demographic, socioeconomic and behavioral factors. The authors suggest the decrease in primary care physician supply across counties could have important health implications, although conclusions about individual-level effects shouldn't be drawn from population-level associations.