By Kenneth E. Thorpe 12 percent of Americans suffer from five or more chronic conditions, such as high blood pressure, heart disease, and diabetes. This fraction of the population accounts for 41 percent of total health care spending. If we don’t do more to prevent people from acquiring chronic disease, the resulting health care bills could blow a gaping hole in the federal budget. A new study conducted by RAND Health and supported by my organization, the Partnership to Fight Chronic Disease, shows just how costly it is to treat the severely ill. In 2014, the latest data available, 32 percent of those with five or more chronic conditions visited an emergency department at least once. ER visits cost over $1,200 on average. The sickest patients also require more prescriptions. In 2014, patients with five or more chronic conditions filled nearly six times the number of prescriptions as people with one or two chronic diseases. Chronic disease prevents people from living independently. More than half of those with five or more chronic conditions report having physical limitations that affect their daily lives. As a result, patients have to cut back on work or ask someone to help them. More than 34 million Americans provide unpaid care to adults who are older than 50. This leads to a loss in worker productivity that could cost society $794 billion by 2030. If we hope to save lives and avoid such staggering costs, we must undertake key reforms to help patients manage and prevent chronic diseases. First, policymakers need to work together to ensure that care is affordable and accessible. A third of privately-insured Americans recently reported receiving a “surprise” medical bill, one in which their health insurance plan paid less than what they expected. And many insurers have started dropping certain prescriptions from their coverage, leaving patients to either try a new drug or to pay for their current drug out-of-pocket. When patients can’t access the care they need, they get sicker — and health care costs rise. Improving medication adherence alone could save America more than $105 billion a year. Second, we ought to expand programs proven to prevent chronic diseases. For instance, the Diabetes Prevention Program, which is offered by private insurers, helps patients at risk of developing diabetes improve their diet and exercise more. The program has worked tremendously well — patients aged 60 or older who made lifestyle changes through the program reduced their risk of developing diabetes by 71 percent. Medicare will cover it for those at risk and age 65 and older starting in 2018, but if Medicare offered the program to at-risk adults aged 60-64, it could save $7 billion more. Altogether, increasing access to health care and promoting behavioral changes could save society $116 billion a year. Finally, America needs to encourage the development of new treatments and medicines. In 2016, there were 93 medicines in development for Alzheimer’s disease, more than 170 for diabetes, and more than 130 for mental illnesses. Fostering the development of medicines and treatments that target chronic disease would save millions of lives and save $418 billion a year. If current trends continue, chronic diseases will claim millions of American lives and cost us trillions of dollars. To lower that toll, we need to promote prevention efforts and improve access to recommended care for those who are already diagnosed. Kenneth E. Thorpe is a professor of health policy at Emory University and the chairman of the Partnership to Fight Chronic Disease.