Researchers at Semmelweis University in Hungary have discovered that pain and fatigue in patients with rheumatoid arthritis can continue even after the inflammation that typically causes these symptoms is under control. Their findings, published in Nature Reviews Rheumatology and The Lancet Rheumatology, suggest that conditions such as depression, poor sleep, obesity, smoking, and chronic pain may play a role in keeping symptoms active, even when the disease itself is in remission. Rheumatoid arthritis is a long-term autoimmune condition in which the body's immune system mistakenly attacks its own joints, causing pain, swelling, and stiffness. In Hungary, it affects thousands of people, and while most patients respond well to treatment, between 6 and 28 percent are classified as "difficult-to-treat" because they do not achieve lasting remission despite medical care. The researchers explored how conditions like depression, smoking, obesity, and sleep problems are linked to difficult-to-treat rheumatoid arthritis. They found that pain and depression can lower physical activity, lead to weight gain, and worsen both sleep and mood. These changes can, in turn, increase pain and make daily tasks more challenging, creating a self-reinforcing "vicious cycle" that is hard to break. The team also developed a new approach to treating difficult-to-treat rheumatoid arthritis. The current "treat-to-target" method involves doctors regularly monitoring signs of disease activity and adjusting treatment if inflammation is not sufficiently reduced. The researchers suggest this approach could also act as an "early warning system" — if inflammation improves but symptoms like pain or fatigue remain, it may indicate that these symptoms are not solely caused by inflammation. In such cases, doctors might look for other causes, such as chronic pain, depression, or sleep disorders, rather than automatically increasing medication. Dr. György Nagy, head of the Department of Rheumatology and Immunology at Semmelweis University, said that when disease indicators improve but the patient still experiences pain and fatigue, doctors should consider alternative factors. This approach has led to better outcomes for difficult-to-treat patients and may improve the doctor-patient relationship by focusing treatment more closely on the actual causes of the patient's symptoms. The team's model has received significant international attention, with their research on "difficult-to-treat" disease and related treatment strategies cited more than a thousand times by other researchers. The concept is now used globally for rheumatoid arthritis and other conditions. Looking ahead, the researchers plan to explore how artificial intelligence can help develop more effective treatments. Dr. Lilla Gunkl-Tóth, a PhD student at Semmelweis University and lead author of the studies, explained that AI-based pattern recognition could help identify patient subgroups and create more personalized treatment strategies.