Sleep quality in subjects suffering from chronic pain

Background Sleeping problems are very common in patients with chronic pain. The aim of the study was to investigate the association between different dimensions of chronic pain and sleep quality in chronic pain patients. Methods In this cross-sectional interview-based questionnaire study, patients from 3 different pain treatment centers in Vienna aged 18-65 years, with pain lasting 3 months or longer were asked to participate. The association between the short-form McGill pain questionnaire (SF-MPQ) and sleep quality (sleep onset latency, interrupted sleep due to pain, sleep duration and recovering effect of sleep) was assessed. Results In this study 121 patients (male 32, female 89, mean age 49 +/- 9 years) could be analyzed. Of the patients 38.8% needed more than 30 min for falling asleep, 63.6% reported sleep fragmentation, 30.6% slept less than 5 h and 60.3% reported no recovering effect of sleep. The strongest associations between pain characteristics and sleep quality were found for pain intensity and affective pain aspects. Logistic regression analyses revealed that one point more in the total score of SF-MPQ increased the odds of needing more than 30 min for falling asleep, waking up more than 3 times due to pain, sleeping less than 5 h, and perceiving the sleep as non-recovering, by 6%. Adjusting for physical and psychological quality of life lowered the odds ratios and the association was no longer significant. Conclusion The results underline the importance of paying attention to sleep quality in patients with chronic pain. The results also indicate that psychological factors might mediate the association between pain and sleep quality.