A federal judge says a waiver allowing Arizona's Medicaid program to charge low-income adults co-pays for medical care was improperly issued and ordered federal officials to review their decision.

U.S. District Judge David Campbell's ruling doesn't stop the state's Medicaid plan from charging co-pays to childless adults covered for visits to doctors and for prescriptions.

But it is the second time a federal judge has ruled that the Health and Human Services Administration improperly allowed Arizona to charge poor people co-pays.

The decision was issued in a case brought by an advocacy group that argues co-pays prevent the very poor from getting medical care. Ellen Katz of the William E. Morris Institute for Justice said Friday she believes it actually costs the state more because people get sicker before treatment.