What It Means for Patients

Crowson says these new figures can be helpful to patients in general because they allow them to compare the lifetime risks of these conditions to the lifetime risks of other well known diseases. She says that may help people decide what if any lifestyle changes they should
consider to reduce their lifetime risk. She says it also puts into context how serious these diseases are compared to other major diseases like:

Coronary heart disease – 1 in 3 women; 1 in 2 men

Stroke – 1 in 5 women; 1 in 6 men

Prostate cancer – 1 in 6 men

Breast cancer – 1 in 8 women

Alzheimer’s disease – 1 in 5 women; 1 in 10 men

Parkinson’s disease – 1 in 75 women; 1 in 50 men

“These figures do help us to understand for the first time just how common these diseases are when taken together.  If we say that,  for example, the risk a woman has of getting breast cancer in her life is 1 in 8, then you can see that the risk a woman has for getting a rheumatic disease is just somewhat lower,” says Eric Matteson, MD, a professor of medicine in the division of rheumatology at the Mayo Clinic in Minnesota who also worked on the study. “Taken together, likelihood of getting one of these diseases is not quite as high as some common cancers, but [it’s] certainly not low. Rheumatoid arthritis is the most common of these diseases, and here the likelihood of getting the disease is for women is about a third of the lifetime risk of getting breast cancer, for example.”

Emily Somers, PhD, is an epidemiologist and assistant professor of medicine and environmental health in the division of rheumatology at the University of Michigan in Ann Arbor. She agrees the new lifetime risk estimates can be very helpful for patients, as long as the numbers are properly explained to them.

“Based on experience with risk communication from other disease settings, such as breast cancer, a common misconception with lifetime risk is that patients may think it is their risk of developing disease within the next year, which clearly could cause undue anxiety,” Somers says. “It is important to recognize such issues when communicating with patients, even when terminology is seemingly obvious to health professionals.”

Imperfect Science

Although the study offers new and interesting numbers, Somers says it’s not without flaws. She points out that the data comes from a relatively homogeneous population that is mostly white.

“Therefore, the risk estimates from this study are most applicable to persons from similar demographic backgrounds,” Somers says. “In order to better estimate risk for the broader U.S. population, it would be important to have data from populations with greater racial, ethnic and socioeconomic diversity. The ideal would be to generate estimates specific for various racial and ethnic groups.”  

The authors mention that in the paper as a limitation, and say that going forward, they would like to get more specific with lifetime estimates by breaking them down by things like risk factors.