New York, June 4 (IANS): Poor sleep can amplify pain in patients with knee osteoarthritis (OA) -- a degenerative joint disease that causes pain and swelling of joints in the hand, hips or knee.

Researchers from Johns Hopkins University School of Medicine in Baltimore, Maryland, found that OA patients who have poor sleep habits displayed greater central sensitisation -- an amplification of clinical pain.

Central sensitisation is a condition of the nervous system that is associated with the development and maintenance of chronic pain.

The findings further showed that OA patients who catastrophise -- consumed by thoughts of pain -- had increased central sensitisation that was associated with greater pain.

"Our study is the largest and the most comprehensive examination of the relationship between sleep disturbance, catastrophising and central sensitisation in knee OA," said lead study author Claudia Campbell from the department of psychiatry and behavioural sciences.

For the study, the team analysed 208 participants.

Results show that the subjects with knee OA and insomnia had the greatest degree of central sensitisation compared to the controls.

The team found patients with poor sleep and high catastrophising scores reported increased levels of central sensitisation.

In turn, central sensitisation was significantly associated with increased clinical pain.

"Understanding the intricate relationship between sleep, central sensitisation and catastrophizing has important clinical implications for treating those with chronic pain conditions such as knee OA," the authors said.

The study was published in Arthritis Care and Research, a journal of the American College of Rheumatology (ACR).