LITTLE ROCK — The number of people who have been deemed eligible for Arkansas’ expanded Medicaid program has reached 317,289, state Department of Human Services Director Cindy Gillespie said Thursday.

In a letter to Gov. Asa Hutchinson, Gillespie said that at the end of August, 265,608 Arkansans were enrolled in private health insurance plans under the program known as the private option, 23,043 who applied for the program were enrolled in traditional Medicaid because they were deemed medically frail, and 28,638 people who had been deemed eligible for the program were in the process of enrolling.

The private option, created in 2013 as an alternative to the expansion of Medicaid rolls envisioned in the federal Affordable Care Act, provides government-subsidized private health insurance to people earning up to 138 percent of the federal poverty level. DHS officials initially estimated that enrollment would peak at about 250,000 people.

Gillespie also reported that the average per-person cost of the program was $480.62 in August. That is within the budget cap of $523.58, the amount per person, per month that the program’s costs cannot exceed without the state being responsible for paying the overage.

The federal government is paying all of the program’s costs now, but in 2017 the state will be responsible for 5 percent of the cost. The state’s share of the cost will increase gradually to a maximum of 10 percent in 2020.

Hutchinson and the Legislature have approved the governor’s plan to make changes to the program and rename it Arkansas Works next year, pending federal approval.

Gillespie also told Hutchinson she is working with state Insurance Commissioner Allen Kerr and Arkansas Health Insurance Marketplace Executive Director Cheryl Gardner to develop a plan for long-term sustainability of the entire Medicaid program, at Hutchinson’s request. She said they will provide the governor with a projection of Medicaid costs over the next five years by Oct. 15.