(RxWiki News) For many older people, joints can get stiff and painful from osteoarthritis. This disease often settles in the knee. While it can be hard to sleep with an aching knee, poor sleep may be contributing to the pain.
A new study found that pain was amplified in patients with knee osteoarthritis who slept poorly. Also, patients who “catastrophize,” or are consumed by thoughts of pain, may experience greater discomfort.
"Numerous studies have established that disrupted and shortened sleep decreases the pain threshold," said Robert S. Rosenberg, DO, FCCP, a board-certified sleep medicine physician and author of "Sleep Soundly Every Night, Feel Fantastic Every Day," in an interview with dailyRx News. "In fact, several studies have demonstrated that loss of slow wave (deep sleep) in particular may result in an increased sensitivity to pain. Patients with fibromyalgia and rheumatoid arthritis tend to manifest increased amounts of lighter sleep."
Dr. Rosenberg added, "Therefore, when one is suffering from an arthritic condition and insomnia, the sleep issue needs to be addressed. Most people attribute the insomnia to their pain. However, as pointed out in these studies, in many it may be the other way around. Having a negative attitude (catastrophizing) can contribute to pain-related sleep disturbances, and as a result, increase sensitivity in the central nervous system to pain."
About 27 million Americans deal with the pain of osteoarthritis, which can affect any joint in the body, according to the Arthritis Foundation. With this condition, cartilage breaks down, leading to pain, swelling and problems moving the joint. As people age, they are more likely to get osteoarthritis. It’s most common in those who are 65 and older.
Claudia Campbell, PhD, of Johns Hopkins University School of Medicine in Baltimore, MD, led this study.
“Our data suggest that those with low sleep efficiency and higher catastrophizing have the greatest central sensitization,” Dr. Campbell said in a press release. “Understanding the intricate relationship between sleep, central sensitization, and catastrophizing has important clinical implications for treating those with chronic pain conditions such as knee osteoarthritis.”
Central sensitization is a condition of the nervous system and is tied to the development and maintenance of chronic pain. The condition involves a heightened sensitivity to pain and the sensation of touch.
Dr. Campbell and her colleagues followed 208 patients. Almost three-quarters were female. They were separated into four groups — osteoarthritis patients with insomnia, osteoarthritis patients with normal sleep habits, healthy patients with insomnia, and healthy patients without pain and with normal sleep.
Dr. Campbell and team evaluated patients based on sleep assessments, psychological and pain evaluations and sensory testing.
Based on their findings, Dr. Campbell and colleagues concluded that patients with knee osteoarthritis and insomnia had the highest level of central sensitization — compared to those in the healthy groups. Patients who did not sleep well and had high catastrophizing scores reported heightened central sensitization. Patients with more central sensitization said they had more pain.
"If you have knee osteoarthritis and are struggling with sleep disturbance, it is important to consider getting a sleep assessment to diagnose issues like sleep apnea (which has its own treatment) and insomnia," Dr. Campbell told dailyRx News. "We have found that for knee osteoarthritis patients with insomnia, a brief behavioral intervention improves sleep and reduces pain. A referral for cognitive behavioral therapy for insomnia may be most beneficial for people that have chronic sleep problems."
This study was published June 4 in the journal Arthritis Care & Research.
Grants from the National Institutes of Health funded this research. Dr. Campbell and team disclosed no conflicts of interest.