Bigger medical groups may deliver better care

Bigger may be better when it comes to the size of a medical practice, researchers from the University of Pittsburgh and the Harvard School of Public Health reported last week in the Annals of Internal Medicine.

On four of six measures of quality, including the percentage of patients who received mammograms, Pap smears or eye exams for diabetics, primary care practices with more doctors scored higher than those with fewer physicians. That finding is contrary to the widespread public perception that the best care is provided by a neighborhood practice consisting of a few doctors.

Researchers led by Ateev Mehrotra, an assistant professor of internal medicine at the University of Pittsburgh School of Medicine and policy researcher at the RAND Corp., compared data from 119 California physicians' groups that contracted with PacifiCare, a large California HMO, for a 12-month period beginning in July 1999.

Their goal was to compare the care delivered in large group practices involving dozens or even hundreds of doctors, such as those employed by Kaiser Permanente or affiliated with large teaching hospitals, with small practices consisting of three or fewer physicians.

Previous studies have analyzed data such as the use of electronic medical records and other technology, but until now no study has examined the delivery of services, such as use of mammography or asthma medication, as markers of quality.

The disparity in mammography was particularly surprising, Mehrotra said: Seventy-three percent of eligible patients in the large medical groups received it, compared with 58 percent in the smaller practices.

While the reasons for the differences in care were unclear, Mehrotra speculated that they might reflect the characteristics of doctors who gravitate to certain kinds of practices. Younger, more recently trained physicians, he said, may be more likely to join the large groups, which might boost the quality of care those patients receive in some areas the researchers analyzed. In two areas, use of asthma medication and prescription of beta blockers after a heart attack, researchers found no difference between large and small practices.

Mehrotra said he is not advising patients to dump their doctors if they practice in small groups.