Smoking is the #1 cause of premature death and preventable illness in the United States. And since one-third of Medicaid participants smoke, compared to 17 percent of the general population, you'd think the states would be all about helping people in their Medicaid programs to quit.

But just 10 percent of Medicaid participants who smoke are getting medication to help them quit, according to a study published Tuesday in the journal Health Affairs. That's 830,000 people in 2013.

Treatments include over-the-counter remedies like nicotine gum and patches, which Medicaid will pay for when a patient has a doctor's prescription, as well as the prescription medications bupropion (Welbutrin) and varenicline (Chantix).

Some states are doing a lot better than others at helping people quit. Massachusetts and Minnesota, which have gone out of their way to promote smoking cessation to Medicaid enrollees, have among the highest treatment rates among Medicaid participants, with more than 20 percent of smokers getting at least one prescription in 2013, the study found.

But Alabama, Arkansas, Kansas, Mississippi, Rhode Island and Texas had rates below 7 percent. "The states that are doing less are also the states that have higher rates of smoking," says Leighton Ku, lead author of the study and director of the Center for Health Policy Research at George Washington University.

And that's costing a lot.

State and federal governments shell out about $70 billion a year to pay for smoking-related health costs through Medicaid, which insures people with low-incomes. But the program spent just $103 million on tobacco cessation medications in 2013, the study authors estimate.

States that didn't expand their Medicaid coverage under the Affordable Care Act tend to have lower rates of medication use. And some states charge Medicaid participants copays for medication, which can discourage use. That's not the case for people with private insurance or Medicare, which are required by the Affordable Care Act to cover prescription cessation meds without a copay.

"And finally, there have not been the kind of education programs saying, gee, this is something we can actually do something about," Ku says.

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