To help prevent overtesting and overtreatment of older patients -- or undertreatment for those who remain robust at advanced ages -- medical guidelines increasingly call for doctors to consider life expectancy as a factor in their decision-making. But clinicians, research has shown, are notoriously poor at predicting how many years their patients have left.

Now, researchers at UC San Francisco have identified 16 assessment scales with "moderate" to "very good" abilities to determine the likelihood of death within six months to five years in various older populations. Moreover, the authors have fashioned interactive tools of the most accurate and useful assessments.

Tuesday, the researchers published a review of these assessments in The Journal of the American Medical Association and posted the interactive versions at a new website called ePrognosis.org, the first time such tools have been assembled for physicians in a single online location.

"We think a more frank discussion of prognosis in the elderly is sorely needed," said Dr. Sei Lee, a geriatrician at UCSF and a co-author of the review. "Without it, decisions are made that are more likely to hurt patients than help them."

Lee and his colleagues cautioned that while the best assessments are reasonably accurate, there is insufficient data on whether using them improves patient care in clinical settings. The researchers stopped short of urging widespread use.

At present, physicians are often shooting in the dark when they recommend tests, treatments and medications for older patients. Older bodies respond differently than younger ones to drugs and operations, many of which are never evaluated in elderly populations.

Even when interventions do work, the benefits can be years away. Doctors have no easy way to know whether their elderly patients will live long enough to experience them. The potential for complications and side effects, however, is immediate.

Plugging individual variables -- age, health conditions, cognitive status, functional ability -- into one of the new online tools produces a percentage indicating the likelihood of death within a particular time frame. Some assessments are used for hospital patients or nursing home residents, others for elderly people still living at home.

The results could help doctors and families evaluate, for example, whether an older person with a terminal disease should consider hospice care, Lee said.

Medicare regulations require that hospice patients have a prognosis of six months or less, but most patients do not turn to hospice until they are within a few weeks or days of death, when there is little time to provide full medical and psychological support.

At ePrognosis.org, physicians can consult the Porock index, used for assessing life expectancy in long-term nursing home residents. The index indicates, for example, that a man in his late 80s with congestive heart failure, failing kidneys, weight and appetite loss, declining cognitive ability and the need for extensive assistance has a 69 percent chance of dying within six months.

Doctors and family members could reasonably conclude that such a person is a candidate for hospice without fearing that they have jumped the gun.