GEOGRAPHIC VARIANCE: Doctor Style The Cause, Says NEJM
A new study attributes geographic variations in the utilization of medical care to "geographic differences in doctors' opinions" on the best treatment approaches. The study, led by Dr. Carol Ashton of the center for Quality of Care and Utilization Studies, used Veterans Administration databases to track hospital stays over five years for eight diseases, including diabetes, kidney failure, depression and angina. Published in this week's New England Journal of Medicine, the study found that some areas have utilization rates more than three times higher than others, with the highest rates in the Northeast and the lowest in the West. Hospital stays for congestive heart failure have the smallest geographic difference, while stays for kidney failure vary the most. The authors arrived at differences in physician opinion as the cause of the variation only after ruling out a number of other potential influences: As VA physicians are salaried, the authors rule out financial incentives in explaining regional differences. The authors also discount hospital bed availability as a viable explanation, since most VA hospitals are oversupplied. Finally, the VA's relatively homogenous patient population consists almost entirely of poor men with similar health profiles, eliminating regional differences in patients' health and socioeconomic status as possible reasons. The authors conclude that VA physicians may "simply have practice styles that are similar to those of other physicians in their geographic regions" (Ashton et al., NEJM, 1/7 issue). Ashton called on the research community to "move forward to discover which usage rate leads to the best outcomes for patients" (VA release, 1/6).
In an accompanying editorial, however, Dr. John Wennberg of Dartmouth Medical School contends that data from "small areas do not support the notion that there is a conformity of practice styles among large regional communities of physicians." For instance, he notes that discharge rates for Medicare patients with lung disease are 2.2 times higher in Boston than in New Haven. He concludes, "If Ashton et al. had compared the patterns of care among the 5 to 10 medical centers in each of the 22 VA networks, the variations within regions would very likely have been greater than the overall variation" (Wennberg, NEJM, 1/7 issue).