California’s low-income residents continue to head straight for the emergency room — instead of their doctor’s office — for expensive treatment, a practice that the Affordable Care Act was supposed to curb.

Three years into Obamacare, new figures show, ER visits by the state’s Medi-Cal patients rose 44 percent from early 2014 to late 2016.

That’s pretty much the opposite of what former President Barack Obama had predicted in 2009, the year before the law was passed. The Obamacare provision expanding Medicaid was designed to get low-income people to start going to doctors in cost-efficient “managed care” plans.

But with a chronic shortage of doctors to treat the Golden State’s 4 million new Medi-Cal participants, Mountain View resident Grace Bennett isn’t surprised the transition hasn’t gone as planned.

“I got my enrollment card and this lovely letter that said, ‘Congratulations! You have a doctor you can call for primary care,”’ recalled the 54-year-old temp office worker, who has epilepsy, “but she refused to see me.’’

Bennett had such a tough time getting any help from the Santa Clara Family Health Plan in 2014 and 2015 that she largely used El Camino Hospital’s emergency room staff for checkups, lab work and prescriptions — and where she said she met other Medi-Cal enrollees in similar situations.

Because the care provided in emergency rooms is so expensive, they aren’t meant to be used for basic health care services. And with about a third of Californians now on Medi-Cal as a result of the Obamacare expansion, that means a bigger bill for federal and state taxpayers.

The Affordable Care Act’s architects had predicted that enrolling more people in Medicaid (called Medi-Cal here) and then assigning each participant a primary care doctor would divert those patients with minor ailments — like the flu or urinary tract infections — away from the ER.

But struggles over accessing physicians or long delays for appointments, experts say, are among the reasons why Medi-Cal patients logged about 1.4 million visits to the ER in the last quarter of 2016. According to the Office of Statewide Health Planning and Development, that’s up from around 1 million in 2014, when the Affordable Care Act took hold.

To many experts, the most obvious explanation for the increase is Medi-Cal’s explosive growth — from a program that served just over eight million people before Obamacare to one that now provides coverage to 14 million Californians.

Chris Perrone, a director at the California Health Care Foundation who focuses on improving access to coverage and care for low-income Californians, said that he’s not surprised by the numbers, but if the figures don’t start dropping noticeably by year’s end, he said, “I would be … alarmed.”

That’s because he thinks it’s taking some time for the previously uninsured adults now receiving Medi-Cal — who once avoided hospital ERs because of the exorbitant bills that awaited them after treatment — to get familiar with their managed care plans.

Now that they’re covered by Medi-Cal, their pent-up demand for health care is often being met 24/7 by ERs. The fact that those using emergency rooms don’t face any penalties for seeking such costly care — coupled with confusion about their new plans — it’s no wonder they head to the hospital for minor aches and pains.

“They know they have a payer source, and they are seeking care — and many are seeking care in the emergency departments,’’ he said.

But Perrone and other health policy experts predict that these high numbers will drop — as they already have from a peak of almost 1.5 million visits in the first quarter of 2016 — as problems are ironed out and enrollees establish a stronger relationship with their primary care doctors.

That said, Perrone acknowledged Medi-Cal’s chronic challenge of finding enough doctors to treat all 14 million participants.

Surveys show only 40 percent of doctors in the state treat 80 percent of Medi-Cal patients, largely because California has one of the lowest provider reimbursement rates in the country.

Hounded by physician groups, Gov. Jerry Brown earlier this month agreed to address the issue by adding $546 million in extra funding for Medi-Cal doctors, dentists and others from the 2016 tobacco tax to the budget year that begins July 1. He and the Legislature also agreed to provide $711.2 million to cover the growth in the program.

Perrone and others hope the cash infusion will widen the pool of doctors to care for these patients — and reduce ER visits. The budget boost is among several financial incentives offered by some health plans around the state. Those include bonuses for doctors who succeed in getting their patients to show up for appointments instead of heading to the ER — and even a chance for new Medi-Cal patients to win $50 gift cards if they get their first exam done within a few months of joining a plan.

Other programs — including physician consultations by email or video, especially for rural residents who don’t live near major medical centers — appear to be effective, Perrone said.

Through a variety of programs, the Central California Alliance for Health, which runs the Medi-Cal programs in Santa Cruz, Monterey and Merced counties, has reduced its patients’ ER visits from 15,003 in early 2015 to 12,472 in the first quarter of this year, said the alliance’s chief medical officer, Dr. Dale Bishop.

The Partnership Health Plan of California, which runs the Medi-Cal programs in 14 North Bay and rural Northern California counties, has seen a 37 percent decrease in emergency room visits from January 2014 through September 2016 by instituting similar incentives, said CEO Elizabeth Gibboney.

Bennett, the Mountain View resident and Medi-Cal enrollee, credits the efforts of Santa Clara County Supervisor Joe Simitian in helping her finally nail down a doctor’s appointment.

Outraged over the nearly two-year delay, she filed a complaint with the Santa Clara County Civil Grand Jury in late 2015 to investigate whether Medi-Cal patients using the Santa Clara Family Health Plan were able to get medical care from physicians listed by the plan.

Last month, after the grand jury released its report and recommendations, plan officials said they were addressing these and other patient concerns.

“What happens to people who aren’t educated — who don’t know how to push for service — when it becomes dire for them?’’ asked Bennett, a former legal secretary. “I think they either go without care — or they go to the nearest emergency room.’’