OKLAHOMA CITY (AP) — Oklahoma voters have narrowly approved amending the state Constitution to expand Medicaid health coverage to tens of thousands of low-income residents. The state question fared well in metropolitan counties, but was overwhelmingly opposed in rural counties. Four other states have expanded Medicaid through ballot questions, but Oklahoma is the first to amend its state Constitution. That will prevent the Oklahoma Legislature from tinkering with the plan or rolling back coverage. The Republican-controlled Legislature and the last two GOP governors have opposed expanding Medicaid. They contend the state’s one-tenth share of the annual cost would be too expensive.