Objectives: This study investigated the bidirectional relationship between the intensity of low back pain (LBP) and sleep disturbance. Further, the study aimed to determine whether any relationship is dependent on pain duration, symptoms of depression and anxiety, and the method of sleep assessment (subjective vs. objective).
Materials and Methods: Eighty patients with LBP completed a sleep diary. A subgroup of 50 patients additionally wore an electronic device (Armband) to measure sleep for 7 consecutive days. Pain intensity was assessed twice daily using a sleep diary. Depression and anxiety symptoms were assessed at baseline using the Depression Anxiety Stress Scale questionnaire. Generalized estimating equations (GEE) with an exchangeable correlation structure were used to examine the relationship between day-time pain intensity and sleep.
Results: The GEE analysis showed that a night of poor sleep quality, difficulty falling sleep (assessed by the sleep diary), waking after sleep onset, and low sleep efficiency (assessed by the sleep diary and Armband) were followed by a day with higher pain intensity. Further, a day with higher pain intensity was associated with a decrease in the subsequent night’s sleep quality, an increase in sleep latency (assessed by the sleep diary), waking after sleep onset (assessed by both measures), and low sleep efficiency (assessed by the Armband).
Discussion: The findings demonstrate that there is a bidirectional relationship between sleep and pain intensity in patients with LBP. The relationship is independent of pain duration and baseline symptoms of depression and anxiety and somewhat dependent on the method of sleep measurement (sleep diary or Armband). Future research is needed to determine whether targeting sleep improvement in patients with LBP contributes to pain reduction.
*Department of Physiotherapy, King Fahd Hospital of the University, The University of Dammam, Khobar, Saudi Arabia
†The George Institute for Global Health, Faculty of Medicine
∥The Woolcock Institute of Medical Research, The University of Sydney
§Department of Health Professions, Faculty of Human Sciences, Macquarie University, Sydney, Australia
‡Neuroscience Research Australia and the School of Medical Sciences, the University of New South Wales, Randwick, Australia
Supported by a grant from the University of Sydney, Sydney Medical School, Sydney, Australia. C.G.M. fellowship is funded by the Australian Research Council, Canberra, Australian Capital Territory, Australia. The authors declare no conflict of interest.
Reprints: Saad M. Alsaadi, MSc, Department of Physical Therapy, King Fahd Hospital of the University. The University of Dammam. PO Box 40035, Khobar 31952, Saudi Arabia (e-mail: firstname.lastname@example.org).
Received February 6, 2013
Received in revised form February 5, 2014
Accepted October 27, 2013