The problem is actually two problems: delivering more efficient care to these patients and helping them not to get sick in the first place.

Both tasks require the cooperation of patients and caregivers, as well as the providers of health care and the agencies that pay for it — and, at least as important, a public willing to take proven steps to reduce the risk of chronic disease.

The statistics, as reported in December in a strategy report from the Department of Health and Human Services, say it all. More than 25 percent of Americans have two or more chronic conditions — which, by definition, require continuing medical care, and often limit their ability to perform activities of daily living. (The conditions include heart disease, diabetes, obstructive lung disease, high blood pressure, kidney disease, osteoporosis, arthritis, asthma, H.I.V., mental illness and dementia, among others.)

As people age, their chances of having two or more chronic conditions rises, andMedicare expenditures rise with them. Two-thirds of Americans over 65 and three-fourths of those over 80 have multiple chronic diseases, and 69 percent of Medicare dollars are spent on people with five or more of them.

And the number of patients is expected to rise sharply in the coming decade as more and more baby boomers enter their late 60s and early 70s. By 2020, the number of people with multiple chronic conditions is expected to increase to 81 million, up from 57 million in 2000.

The new report, “Multiple Chronic Conditions: A Strategic Framework,” was created to provide “a road map for the nation to foster changes in the health care system that can reduce poor health outcomes, improve patients’ quality of life and reduce costs,” said Dr. Anand K. Parekh, an assistant secretary of health who was in charge of the report.

“With an aging population, the persistence of risk factors for disease and the marvels of modern medicine, more people are living with multiple chronic conditions,” Dr. Parekh said in an interview. “New care models are needed to provide coordinated care.”

The Problems

It’s not just the number of conditions people have, nor the number of people who have them. Because of the way medicine is typically practiced these days, people with multiple chronic diseases commonly receive disjointed, often conflicting care. That can lead to preventable hospitalizations and a host of avoidable complications, adverse reactions to treatment, and duplication of expensive, sometimes hazardous tests.

Clinical practice guidelines have been developed to help doctors treat patients with many individual chronic conditions, but not for treating common combinations of them. As a result, what is recommended for one disease may counteract what should be done for another.

Dr. A may prescribe something for a heart problem that reacts badly with what Dr. B prescribed for the same patient’s asthma or what Dr. C prescribed for arthritis or osteoporosis.

When no one doctor coordinates and oversees a patient’s total care, or when patients neglect to report all the other prescribed and over-the-counter remedies they take, medical cocktails can become Molotov cocktails.

Often, patients have no idea that a particular treatment is the cause of distressing new symptoms, which can result in an emergency room visit, hospitalization and a raft of costly tests. Even without such emergencies, patients with multiple conditions are often subjected to the same tests by different doctors, contributing further to needless medical expense.

Medications can often be avoided with self-care activities like reducing salt, eating lots of vegetables and fruits and getting regular exercise.

But the doctors’ offices seldom have anyone on staff to help patients develop such routines and stick with them. And medical insurance rarely covers the services of nutritionists and exercise physiologists.

And Some Solutions

Dr. Mary E. Tinetti, a geriatrician at the Yale School of Medicine, says patients with multiple conditions should always be asked what their goals are: to live as long as possible, to be as functional as possible or to be as free of symptoms as possible?

“There’s always a trade-off; you can’t have it all,” Dr. Tinetti said in an interview. “You have to decide what’s most important to you and let the doctors and nurses know your goal. You have to ask, ‘Given all my diseases, what’s the best way to reach my goal?’ ”

When more than one disease is involved, she said, “what may be good for a given disease may not be good for the patient.” The doctor’s job is to choose “a combination of treatments that is most likely to help and not hurt.”

And since “every treatment a patient gets may make something else worse,” Dr. Tinetti said, when a new remedy is prescribed, the patient or caregiver should ask, “What’s this going to do to my other health problems?”

Dr. Parekh stressed the importance of having a single doctor — usually a primary care physician — to serve as “the quarterback of care for individuals with multiple chronic conditions,” the overseer who can coordinate all the patient’s conditions, medications, tests and specialists.

Electronic health records, which store all a patient’s information in one place, are critical to enhancing communication between providers and avoiding adverse drug interactions, said Christine Vogeli, a health policy expert at Massachusetts General Hospital. And after any hospitalization, she said, patients should have “a face-to-face visit” with their primary care doctor, who can reconcile any contradictory treatments and reduce the risk of rehospitalization.

In one medical model being fostered under the new federal health care law, so-called accountable care organizations of family physicians and specialists (and sometimes hospitals) join forces to improve care and reduce costs, with financial rewards for those who meet performance goals.

In another model, several primary care physicians may practice together, assisted by nurse practitioners who periodically check on patients to be sure they follow prescribed remedies and to uncover problems before they become medical crises.

But patients also have a critical role, Dr. Parekh said. They need to learn as much as they can about their conditions; tell the doctor about every medication and test taken, along with behavioral health problems like mental illness and substance abuse; and avoid risk factors like poor nutrition, smoking, alcohol abuse and lack of physical activity.

“The same risk factors that cause a chronic condition can also make it worse,” he said.