BOSTON - Hospitalized against her will for depression 43 years ago, Judi Chamberlin of Arlington has devoted the decades since to championing patients' rights. She authored a seminal book touting patient control in mental health treatment, helped mobilize a movement, and won a following.

Now the 64-year-old activist is dying of chronic obstructive pulmonary disease, an incurable lung disorder. Chamberlin's final wishes are to die the way she has lived, on her own terms. Late last year she halted hospitalizations and instead opted for home hospice care, which manages pain and emotional needs, but offers no curative treatments.

She had no idea she would end up fighting for herself the same battle she has long fought on behalf of others.

Her insurance company recently informed her that she has "used up" her hospice coverage. That benefit is limited to $5,000 in her insurance policy. She can, they said, file an appeal for an extension.

Hooked up to a portable oxygen tank, and often gasping for air, Chamberlin says this battle doesn't make sense; hospice care is not only her preference, it will cost her insurance company less.

"It just seems so counterintuitive when you think about what [the insurance company] paid for me in 2008," she said.

"They paid thousands of dollars for me to be in the hospital all of the time."

A spokesman for Chamberlin's insurer, UnitedHealthcare, said company case managers have offered to help her with the paperwork for an appeal.

"I wish there was a clearer process," said Dale Kurschner, UnitedHealthcare spokesman. "Benefits do get used up. Our care managers spend a lot of time, day in and day out, figuring out how members can get the care they need."

In Massachusetts and across the country, the price tag for end-of-life care is under scrutiny as the population ages, and leaders search for ways to rein in soaring healthcare costs.

Billions of dollars are spent each year in the United States on intensive treatments for aging patients in the last six months of their lives, according to the 2008 Dartmouth Atlas of Health Care. A 2007 Duke University study concluded that hospice use reduced Medicare expenditures by an average of $2,309 per hospice user during the last year of life.

"There is that light bulb moment, that a lot of people don't want to die expensively in a way that could bankrupt their families. They would prefer to be at home and be comfortable," said Rigney Cunningham, executive director of the Hospice & Palliative Care Federation of Massachusetts.

Cunningham is a member of a new state panel that is developing proposed regulations to improve end-of-life care in the least expensive way possible.

Chamberlin's hospice has assured her they won't abandon her, but she worries that her daughter and her partner may be saddled with thousands of dollars in unreimbursed hospice bills when she's gone.

Her fears run deep.

"My mother had a gruesome hospital death" from breast cancer, Chamberlin said, describing her mother's struggle to breathe, miserable and surrounded by machines as specialists hovered over her, suctioning fluid from her lungs in her last hours of life.

The experience, she said, persuaded her father to choose home hospice care six years ago as he rapidly declined from congestive heart failure.

"He wanted to die in his bed," she said. "He was relaxed and at peace."

In choosing to follow her father's footsteps, Chamberlin said she never envisioned that her hospice path would include such a battle.

Neither did her primary care provider.

"I have never had an insurance company call me and say a patient has exhausted her hospice," said Nancy Boucher, the administrator at Chamberlin's physician's office, Arlington Family Practice, helping her with her appeal.

"I was devastated when they called me about her case," Boucher said.

"You mean this woman can't have hospice because she didn't die fast enough?"

Increasingly, insurance companies and employers are offering more generous hospice coverage than what is provided in Chamberlin's plan, said Judi Lund Person, a vice president at the National Hospice and Palliative Care Organization.

More typical is coverage for six months of care, with options for extensions.

The majority of patients die within six months, state and national data show, usually because they don't choose hospice until days before their death.

Last Friday, Chamberlin mailed her completed appeal form to UnitedHealthcare.

She explained her diagnosis, detailed her repeated hospitalizations in 2008, and told of her decision, along with her doctors, to choose hospice care instead.

"Although I apparently haven't died fast enough," she wrote in the "reason for request" section, "I do have a terminal illness and will need some method of care."

And she concluded, "Since I become eligible for Medicare in October 2009, the plan's obligations would end then (providing I am still alive.)"