Doctors have been slowly moving to larger and larger practices for decades. Using figures from the Centers for Medicare and Medicaid Services' Physician Compare database, David B. Muhlestein and Nathan J. Smith, both of Leavitt Partners in Salt Lake City, reported in Health Affairs that the pattern continued in the past few years, in many cases even picking up speed.
Small practices, those with less than ten physicians, lost market share in all states except Idaho and Alabama. At the same time, the largest practices -- those with more than 100 physicians -- grew everywhere except for Kentucky and Arkansas.
Muhlestein and Smith suggested a number of explanations for the trend: increasing technical challenges to running a practice, the rush to population-based contracting settlements, and older physicians in small practices moving out of the workforce.
The authors cautioned that increased consolidation could lead to government intervention. As for the practical implications, they pointed to research showing both positive and negative effects.
"Decreased competition among physicians has been shown to lead to higher prices, but larger groups have also been found to provide better outcomes and lower population costs," they wrote.
The map below shows the change in the number of doctors that reported working in the smallest practices, those with fewer than ten physicians, between 2013 and 2015.