Supersize it. That appears to be the trend in practice size among physicians in the U.S., based on a study in the September issue of Health Affairs that reported more than a quarter of physicians worked in groups of 100 or more in 2011.
The study singled out cardiology to provide a local-level demonstration.
Consolidation into larger physician groups is a recognized phenomenon, wrote lead author W. Pete Welch, a senior policy analyst with the U.S. Department of Health and Human Services, and colleagues. Most analyses have relied on surveys with self-reported data and sample size limitations. They took advantage of recently available national provider numbers in Medicare claims and linked claims from 2009 to 2011 with information from the Medicare provider enrollment database to measure group sizes over time as well as physician characteristics.
Using that approach, “we found that the concentration of physicians in large medical groups is much greater than has previously been reported and that it continues to grow,” wrote the authors. Of the physicians who submitted Medicare claims in 2009, 30.9 percent worked in groups of 50 or more physicians. That figure grew to 35.6 percent in 2011.
In 2009, there were 449 practices that employed more than 100 physicians; in 2011, there were 528, claiming about 27 percent of physicians.
The number of solo practices and group practices with 50 or less physicians declined over the two years. In 2009, 112,524 physicians had a solo practice; but by 2011, 107,853 physicians favored the solo model while 206,837 practiced in groups of 50 or more. Physicians who were 40 years old and younger and women were less likely to choose a solo practice in 2011 compared with 2009.
“[S]eparate from market power, referrals and other practice-level considerations may play some role in the consolidation of physicians,” they wrote. “The landscape, however, is varied: In some metropolitan areas, concentration in narrow specialties such as cardiology is more noteworthy than elsewhere.”
In an analysis of specialties by practice size at the local level, they found that being the sole cardiologist in a group practice was common in the region that included Miami in 2011, with 40 percent of cardiologists in that position while 30 percent practiced in groups with 11 to 50 cardiologists. The pattern was the opposite in Charlotte, N.C., where 10 percent served as the only cardiologist in a group and 61 percent practiced in groups with 11 to 50 cardiologists.
Referral regions with Boston, Nashville and Philadelphia each had two practices with 51 to 100 cardiologists and Cleveland and Indianapolis each had one practice with 51 to 100 cardiologists. No practice had more than 100 cardiologists.
The findings may help frame questions for futures studies, including potential savings, prices and changes in quality of care and access associated with increasing practice size. “A national database of physician group practices could support research on these and related issues,” they suggested.