New research shows that where seniors live makes a difference in the medications they're prescribed. Some miss out on key treatments while others are more likely to get riskier ones.

The Dartmouth Atlas Project found more than 1in 4 patients on Medicare's prescription drug plan filled at least one prescription for medications long deemed high-risk for . Those who live in Alexandria, La., were more than three times as likely as those in Rochester, Minn., to get those potentially harmful drugs.

On the flip side, twice as many heart attack survivors got proven cholesterol-lowering statin drugs in Ogden, Utah, than in Abilene, Texas.

Researchers said there was no good reason for that kind of variation; it can't be explained by sicker patients in different parts of the country.