From The Relationship Between Geographic Variations and Overuse of Healthcare Services, by Salomeh Keyhan and colleagues:
Results: Five papers examined the relationship between geographic variations and overuse of healthcare services. One study in 2008 compared the appropriateness of coronary angiography (CA) for acute myocardial infarction in high-cost areas versus low cost areas in the Medicare population and found largely similar rates of inappropriateness (12.2% vs. 16.2%). A study in 2000 using national data concluded that overuse of CA explained little of the geographic variations in the use of this procedure in the Medicare program. An older study of Medicare patients found similar rates of inappropriate use of CA (15% to 17% vs. 18%), endoscopy (15% vs. 18% 19%), and carotid endarterectomy (29% vs. 30%) in low-use and high-use regions. A small area reanalysis of data from this study of 3 procedures found no evidence of a relationship between inappropriate use of procedures and volume in 23 adjacent counties of California. Another 2008 study found that inappropriate chemotherapy for stage I cancer was less common in lowcost areas compared with high-cost areas (3.1% vs. 6.3%).
Conclusions: The limited available evidence does not lend support to the hypothesis that inappropriate use of procedures is a major source of geographic variations in intensity and/or costs of care. More research is needed to improve our understanding of the relationship between geographic variations and the quality of care.
The way one measures whether care is appropriate or inappropriate is against some established, generally accepted guideline. That’s what the papers reviewed did. However, if such a guideline exists, as it does for some types of care, patterns of over- and under-use should exhibit a low degree of geographic variation. It is for care for which one cannot so easily measure what is and is not appropriate (e.g., which prostate cancer treatment should be applied) that one should expect a greater degree of geographic variation. In the coming weeks I’ll say more about this subject.
Examining geographic variation in guideline-driven care is a bit like searching for one’s keys under the streetlamp. Just because one can see clearly doesn’t mean it’s the right place to look.