CHICAGO — Even if the percentage of Americans who are obese stays the same, diabetes cases will nearly double in the United States in the next 25 years, and the cost of treating the disease will almost triple, according to a study by researchers based at the University of Chicago.
The study, published Friday in the journal Diabetes Care, found the number of people with diagnosed and undiagnosed diabetes will climb from almost 24 million this year to about 44 million in 2034.
Over the same period, annual diabetes-related treatment costs are expected to increase from $113 billion to $336 billion in 2007 dollars.
Alarmingly, Medicare spending on diabetes is expected to jump from $45 billion to $171 billion and could exceed current projections for all Medicare costs, the researchers said. Much of the increase in cases and costs will be driven by aging baby boomers, the 77 million Americans born between 1946 and 1957.
"It's a combination of the increasing numbers of people who have diabetes along with the cost of treating diabetes that gives us these frightening numbers," said study co-author Dr. Elbert Huang, professor of medicine at the University of Chicago.
"The study reinforces the importance of public health efforts to prevent diabetes — by transforming the way we eat and increasing the amount of exercise we do — and emphasizes the importance of finding new ways of treating diabetes efficiently."
Huang also said the study's findings could be considered conservative because the researchers' estimates are based on stable obesity rates.
The number of people becoming obese has risen steadily for many years, though the authors predict that obesity levels among people who don't have diabetes will top out in the next decade, then decline slightly, from 30 percent today to about 27 percent by 2033.
Costs related to diabetes are rising in part because the disease is striking people at younger ages, which can mean more time to develop expensive complications. Diabetes is the leading cause of blindness, amputations and end-stage kidney disease.
"The study was entirely consistent ... with previous reports that the growth in diabetes is substantial and ever-increasing, and the costs of diabetes also are substantial and ever-increasing," said Dr. David Kendall, chief scientific and medical officer for the American Diabetes Association.
Earlier this month, a separate team of researchers at Loyola University Health System reported that more diabetics are becoming morbidly obese. It found that one in five people with Type 2 diabetes are morbidly obese, or 100 pounds or more overweight.
About 90 percent of diabetics have Type 2, which occurs when the body becomes resistant to the effects of insulin or doesn't make enough insulin. Type 1 diabetes is a chronic condition in which the pancreas produces little or no insulin.
Dr. Holly Kramer, lead study author and professor of preventive medicine at Loyola University Medical Center, said the two studies go hand in hand because obesity is the main environmental risk factor for diabetes.
Focusing solely on overall obesity rates minimizes the magnitude of a massive public health problem, Kramer and her colleagues wrote in their report, published online in the Journal of Diabetes and its Complications. "When you are 100 pounds or more overweight, losing a substantial amount of weight and keeping it off is incredibly difficult," Kramer said.
"The cost of care is going to rise substantially because these people are going to have co-morbid conditions in addition to their diabetes — likely more than one — such as heart disease, end-stage kidney disease, arthritis, sleep apnea and fatty liver disease."
Kramer and colleagues reported that about 62 percent of U.S. adults with Type 2 diabetes are obese and about 21 percent are morbidly obese. Among black adults with diabetes, one in three is morbidly obese.
Huang and his colleagues analyzed data from the Centers for Disease Control and Prevention's National Health and Nutrition Examination Survey and the National Health Interview Survey regarding people aged 24 to 85. Kramer and her research team worked with data from surveys completed from 1976 to 2006.
The study developed a new model for forecasting future direct spending on diabetes and was conducted to help predict the impact of various policy scenarios as Congress debates health reform, particularly possible changes to Medicare.