Nocturnal pain, is the pain different compared with pain during the day? An exploratory cross-sectional study in patients with hip and knee osteoarthritis.

Nocturnal pain is an important part of the pain experience in osteoarthritis (OA) and highlighted as key concern by patients with hip and knee OA. Reports have shown a wide range in prevalence of nocturnal hip and knee pain in OA patients (14%­85%). We found that participants with nocturnal pain (76/101 = 75%) were more often affected by both intermittent and constant pain, reported higher pain scores for pain at its worst and pain had more impact on their sleep compared with those without nocturnal pain. Participants with nocturnal pain scored higher visual analogue scale (VAS) scores for their nocturnal pain compared with their pain at the moment. On the other hand, they scored the pain expressed in words higher for their day pain than for their nocturnal pain. More research is needed to explore factors that associate with nocturnal pain and to explore how healthcare professionals can support people with nocturnal pain.