Study: New blood test may detect early onset of osteoarthritis

According to the U.S. Centers for Disease Control and Prevention, 1 in every 2 people living in the U.S. are likely to develop some form of knee osteoarthritis by the time they're 85 years old. Meanwhile, over 52.5 million Americans have been diagnosed with some additional form of arthritis.

For years scientists have been attempting to find new detection methods for osteoarthritis. New research led by the University of Warwick in the U.K. found what may be the first effective blood test for identifying the early stages of osteoarthritis. This type of testing has the potential to detect the condition several years before patients begin to feel symptoms. The findings were recently published in the journal Scientific Reports. 

New biomarker linked to OA and RA
The researchers found a biomarker that has been linked to both rheumatoid arthritis and osteoarthritis. This marker, citrullinated proteins, was found in the blood stream of people experiencing the onset of both these conditions during a blood test performed as the first part of the study. Although it had previously been discovered that CPs are present in patients with rheumatoid arthritis, the fact that those with osteoarthritis have it in their blood as well is a new discovery.

"This is a remarkable and unexpected finding. It could help bring early-stage and appropriate treatment for arthritis which gives the best chance of effective treatment," said lead researcher Naila Rabbani, reader of experimental systems biology at Warwick.

After the blood test, a single algorithm combining three biomarkers, CPs, anti-CP antibodies and the bone-derived substance hydroxyproline, was created by the scientists. They found that one test could not only detect, but distinguish between the common forms of arthritis before any serious damage is inflicted to the joints. 

Rabbani explained the role of CPs in relation to both RA and OA and how the algorithm helps the research.

"It has been long established that the autoimmunity of early-stage RA leads to antibodies to CPs, but the autoimmunity, and hence antibodies, are absent in early-stage OA. Using this knowledge and applying the algorithm of biomarkers we developed provides the basis to discriminate between these two major types of arthritis at an early stage," she said.

Rabbani and her colleagues are hoping to perform further tests to confirm the findings and begin treating patients who are likely to develop either osteoarthritis or rheumatoid arthritis before side effects of the debilitating diseases begin to take a toll on their mobility. 

Why are these findings important?
The study's findings are essential, as the blood test does even more than identify the early stages of osteoarthritis. 

"Detection of early stage-OA made the study very promising and we would have been satisfied with this only – but beyond this we also found we could detect and discriminate early-stage RA and other inflammatory joint diseases at the same," said Rabbani. "This discovery raises the potential of a blood test that can help diagnose both RA and OA several years before the onset of physical symptoms."

Osteoarthritis is a slow-developing disease that occurs when the protective cartilage layer inside joints wears away after a lifetime of stress. Although it usually begins to show symptoms in people 60 years or older, if doctors are able to detect the condition early, they could prevent the deterioration of joints before people reach old age and the disease strikes.

Rheumatoid arthritis usually impacts younger patients, starting at 20 years old, and is more common in women. The condition is so debilitating that nearly half of those impacted are unable to have a full-time job within 10 years of developing the condition, according to Medical News Today. The new blood test could drastically reduce the number of patients impacted by these diseases.