However, the study suggests that doctors in some areas prescribe more readily. The highest number of prescriptions filled was in Miami -- 63 -- and the lowest in Grand Junction, Colo., 39.
Overall, patients in regions where Medicare Part D spent more on medications weren't more likely to receive the most effective medications, the study found.
Yes, seniors who are sicker will use more medications, but the general health of a region's Medicare population explains less than a third of the variation, the researchers concluded.
Patients don't always fill their prescriptions, because of cost or fear of side effects or myriad other reasons -- something this study couldn't measure. It also didn't examine differences in benefits between less- and more-expensive Part D plans.
However, if doctors were following guidelines on best medication practices, there would be far less variation around the country, Munson said.
Doctors "really need to ask themselves, 'Is there a good reason why my patients are getting less-effective care than patients in the other regions,'" he said.
He urged patients to ask more questions, too: Why is this medicine being prescribed? What are the pros and cons? Is there something else I should consider taking?
The Dartmouth Atlas, funded by the Robert Wood Johnson Foundation, studies health trends using Medicare data; similar figures aren't readily available for the general population.