It may seem counter-intuitive but a spate of recent studies shows that faith-driven pursuits of aggressive treatment for life-threatening illnesses can actually subject patients to needless suffering:

“There’s a sense that by not going for life-prolonging care, they’re letting God down.”

In a study published today in the Journal of the American Medical Assn., researchers found that terminally ill cancer patients were nearly three times more likely to go on breathing machines or receive other invasive treatments if religion was an important part of their decision-making process. Such treatments didn’t improve a person’s long-term chances, however.

“There’s a sense that by not going for life-prolonging care, they’re letting God down,” said Holly Prigerson, director of the Center for Psycho-oncology and Palliative Care Research at the Dana-Farber Cancer Institute in Boston and the study’s senior author. “But the more aggressive care you get, the worse your quality of life in that last week.”

Other recent studies have made similar connections. Religious cancer patients who had unsuccessful chemotherapy treatments were twice as likely to want heroic end-of-life measures, according to a report last year in the Journal of Clinical Oncology. A 2005 study in the Annals of Behavioral Medicine found that patients with advanced-stage lung or colon cancer were more likely to want CPR, mechanical ventilation and hospitalization if they believed in divine intervention. They were also less likely to have a living will.

And in a survey of 1,006 randomly selected Americans, published last year in the Archives of Surgery, two-thirds said religious faith would influence their decisions about medical treatment if they were severely injured. More than half said God could heal patients whom doctors thought were beyond the reach of medicine.

Doctors and professional caregivers need strategies to cope with extremely devout patients who view refusing treatment as choosing death, experts say.