The number of active advanced practice registered nurses in Hawaii who provide primary care nearly doubled since 2005 as the state continues to face a shortage of doctors.

APRNs, who can care for patients without physician supervision, grew to 958 in 2015 from 535 in 2005, according to the latest survey conducted by the Hawaii State Center for Nursing.

There are about 19,000 nurses in the state, including registered nurses, who administer medication and treatment to patients, and licensed practical nurses, who provide basic medical and nursing care. APRNs have the highest level of licensure and may prescribe medicines.

“While they are still a small workforce, they are growing exponentially,” said Laura Reichhardt, director of the Center for Nursing. “Absolutely the increased numbers of APRNs in the state are contributing to the primary care workforce. They’re working in ambulatory care, in physicians’ offices and community health centers.”

Hawaii is short about 500 doctors, with the greatest need for primary care physicians particularly on the neighbor islands, according to the University of Hawaii John A. Burns School of Medicine.

Jessica Nishikawa, a family nurse practitioner at Straub Clinic &Hospital who teaches advance practice nursing at Hawaii Pacific University, said APRNs are the future of primary care.

“They can practice autonomously, diagnose and treat problems and (advocate) health prevention and promotion,” she said. “In primary care there really isn’t a difference between what a physician and nurse practitioner can do in the state of Hawaii.”

About 75 percent of nurse practitioners are in primary care after they graduate, compared to less than one-third of physicians who go into the field, she said.

“When you look at the number of residents coming out of medical school going into primary care, there’s not very many,” Nishikawa said. “It’s a little bit misleading in that some of the numbers of primary care residents actually has improved, but a lot of them are foreign resident graduates so they’re probably going to go back and practice medicine in their country.”

Most APRNs hold doctorate degrees in nursing practice, which means they have four-year nursing degrees plus another three years of advanced training.

“The national movement is for getting all of these nurse practitioners doctorally prepared into entry of practice,” she said. “There’s a lot of nurse practitioner programs now. It’s only a matter of time before … there will be an influx of nurse practitioners compared to physicians in primary care.”

Nationally, the number of primary care nurse practitioners is projected to increase by 30 percent to 72,100 by 2020 from 55,400 in 2010, according to the Health Resources and Services Administration.

“Nationally there’s a huge need for APRNs,” said Sandra LeVasseur, associate director of research for the Center for Nursing. “Programs have changed dramatically the last few years in an effort to increase the number of graduates. They’re more specialized in regards to need and demand and totally different from RNs who basically work across all health-care settings.”

By 2020, there will be an estimated shortage of 20,400 primary care physicians across the country. The shortage could be reduced to 6,400 primary care providers if nurse practitioners and physician assistants are utilized more in the health care system, HRSA said.

“It’s a big solution,” Nishikawa said. “Every clinical study that’s ever been done has shown that with nurse practitioners compared to MDs, the clinical outcomes are the same for the patient if not better. The care that we provide is very good … high-quality care.”