Nearly a quarter of primary care doctors in the United States say their practices are not well-prepared to manage patients with multiple chronic illnesses, according to an international survey. The 2015 Commonwealth Fund International Health Policy Survey of Primary Care Physicians, released Monday, surveyed doctors in 10 countries, including the United States, Canada, Germany, Australia, and Sweden. Doctors in the United States and Canada felt least prepared among the countries surveyed to handle patients with multiple chronic conditions. These patients are becoming more common. Aging populations mean more people suffering from degenerative conditions such as dementia and physical frailty.