Genetics Suggest Adult & Child Arthritis Aren’t So Different

“We should study these cases together to better understand exactly the significance of age of onset,” noted Dr. Nigrovic. “We miss opportunities to see how early-onset disease might be different from diseases that manifest later when our terms block pediatric and adult rheumatologists from talking to each other.”

Still Reasons to Treat Adult/Pediatric Patient Differently

Even if most arthritic diseases cross the age divide at the 16th birthday, Dr. Nigrovic emphasizes that reasons to treat children and adults differently do exist. In diseases that are genetically similar, treatment may vary because clinical features differ.

The care of children requires a different infrastructure from the care of adults. Pediatric doctors factor in how treatments impact growth and development, and have to pay close attention to arthritis-associated uveitis (eye inflammation) that is much more common in children. In contrast, adults have greater exposure to environmental exposures, such as smoking and alcohol, and more comorbidities, such as cancer, diabetes and heart disease.

“I’m not suggesting that we blow up the pediatric/adult siloes,” says Dr. Nigrovic. “Rather, we need to keep our thoughts very clear that when we treat kids differently from adults it isn’t necessarily because the disease is different, but because the factors surrounding this patient are. Age doesn’t necessarily make the disease different just because the context is altered.”

Increase Understanding of Age Effects on Biology

Changing the nomenclature may increase the understanding of how age of onset affects disease biology. It is nearly impossible under the current nomenclature to study those under 16 together with adults.

“This makes research on disease etiology and treatment more difficult on both sides of 16,” says Dr. Nigrovic. “It is hard to work together when rheumatologists are forced to use different names and definitions on the two sides of this arbitrary age divide. When the diseases are biologically more similar than different, we should be able to use the same words.”

Focus on Arthritis—Not Age

The review suggests that clinicians and researchers should not be focusing on adult and juvenile forms of arthritis, but rather with forms of arthritis, period. Going forward, there is a good possibility that these clusters will be able to be subdivided into discrete diseases as our understanding of the genetics and biology matures.

“The basic idea is in one sense totally obvious and in another quite subtle,” says Dr. Nigrovic. “I don’t know anywhere else in medicine where age of onset is used like this to define disease groups. It is a historical curiosity within rheumatology, but one with real implications for how we conceptualize our diseases and care for our patients. If we can break out of this way of thinking, then we and our patients will be better off.”

‘There is no disease in arthritis that has the same name on both sides of this age wall [age 16]. If you think about it, that is sort of absurd.’ —Dr. Nigrovic

Unique Conclusion

Dr. Brescia