Accessible Unlicensed Requires Authentication Published by De Gruyter April 12, 2021

Sleep disturbance in patients attending specialized chronic pain clinics in Denmark: a longitudinal study examining the relationship between sleep and pain outcomes

Henrik Bjarke Vaegter ORCID logo, Mette Terp Høybye, Frederik Hjorth Bergen and Christine E. Parsons



Sleep disturbances are highly prevalent in patients with chronic pain. However, the majority of studies to date examining sleep disturbances in patients with chronic pain have been population-based cross-sectional studies. The aims of this study were to 1) examine the frequency of sleep disturbances in patients referred to two interdisciplinary chronic pain clinics in Denmark, 2) explore associations between sleep disturbances and pain intensity, disability and quality of life at baseline and follow-up, and 3) explore whether changes in sleep quality mediated the relationships between pain outcomes at baseline and pain outcomes at follow-up.


We carried out a longitudinal observational study, examining patients enrolled in two chronic pain clinics assessed at baseline (n=2,531) and post-treatment follow-up (n=657). Patients reported on their sleep disturbances using the sleep quality subscale of the Karolinska Sleep Questionnaire (KSQ), their pain intensity using 0–10 numerical rating scales, their pain-related disability using the Pain Disability Index (PDI), and quality of life using the EuroQol-VAS scale. The average time between baseline and follow-up was 207 days (SD=154).


At baseline, the majority of patients reported frequent sleep disturbances. We found a significant association at baseline between self-reported sleep disturbances and pain intensity, pain-related disability, and quality of life, where greater sleep disturbance was associated with poorer outcomes. At follow-up, patients reported significant improvements across all pain and sleep outcomes. In two mediation models, we showed that changes in sleep disturbances from baseline to follow-up were significantly associated with (i) pain intensity at follow-up, and (ii) pain disability at follow-up. However, baseline pain intensity and disability scores were not associated with changes in sleep disturbances and, we did not find evidence for significant mediation of either pain outcome by changes in sleep disturbances.


Self-reported sleep disturbances were associated with pain outcomes at baseline and follow-up, with greater sleep disturbances associated with poorer pain outcomes. Changes in sleep quality did not mediate the relationships between baseline and follow-up scores for pain intensity and disability. These findings contribute to a growing body of evidence confirming an association between sleep and chronic pain experience, particularly suggestive of a sleep to pain link. Our data following patients after interdisciplinary treatment suggests that improved sleep is a marker for a better outcome after treatment.

Corresponding author: Henrik Bjarke Vaegter, PhD, Pain Research Group, Pain Center, University Hospital Odense, Odense, Denmark; and Department of Clinical Research, Faculty of Health Sciences, University of Southern Denmark, Heden 7-9, Indgang 200, DK – 5000, Odense C , Odense, Denmark, Phone: +45 65413869, Fax: +45 65415064, E-mail:

  1. Research funding: CP received funding from TrygFonden (grant number 117642).

  2. Author contributions: All authors have accepted responsibility for the entire content of this manuscript and approved its submission.

  3. Competing interests: There are no actual or potential conflicts of interest for any of the authors.

  4. Informed consent: Written informed consent (electronic) was obtained from all patients included in this study.

  5. Ethical approval: The Danish Data Protection Agency approved the data collection (ref. no. 18/35221), and the conduct of this study complied with the Declaration of Helsinki. No ethics approval was needed (Act on Research Ethics Review of Health Research Projects, October 2013, Section 14.2).


1. Purushothaman, B, Singh, A, Lingutla, K, Bhatia, C, Pollock, R, Krishna, M. Prevalence of insomnia in patients with chronic back pain. J Orthop Surg 2013;21:68–70. Search in Google Scholar

2. Majid, B, Arif, MA, Saeed, R, Ahmed, A, Fatima, M. Frequency and severity of insomnia in chronic low back pain. Rawal Med J 2017;42:528–30. Search in Google Scholar

3. Bahouq, H, Allali, F, Rkain, H, Hmamouchi, I, Hajjaj-Hassouni, N. Prevalence and severity of insomnia in chronic low back pain patients. Rheumatol Int 2013;33:1277–81. Search in Google Scholar

4. Alföldi, P, Wiklund, T, Gerdle, B. Comorbid insomnia in patients with chronic pain: a study based on the Swedish quality registry for pain rehabilitation (SQRP). Disabil Rehabil 2014;36:1661–9. Search in Google Scholar

5. Choy, EHS. The role of sleep in pain and fibromyalgia. Nat Rev Rheumatol 2015;11:513. Search in Google Scholar

6. Ohayon, MM. Prevalence and correlates of nonrestorative sleep complaints. Arch Intern Med 2005;165:35–41. Search in Google Scholar

7. Koffel, E, Kroenke, K, Bair, MJ, Leverty, D, Polusny, MA, Krebs, EE. The bidirectional relationship between sleep complaints and pain: analysis of data from a randomized trial. Health Psychol 2016;35:41–9. Search in Google Scholar

8. Finan, PH, Goodin, BR, Smith, MT. The association of sleep and pain: an update and a path forward. J Pain 2013;14:1539–52. Search in Google Scholar

9. Finan, PH, Smith, MT. The comorbidity of insomnia, chronic pain, and depression: dopamine as a putative mechanism. Sleep Med Rev 2013;17:173–83. Search in Google Scholar

10. Tang, NKY, Lereya, ST, Boulton, H, Miller, MA, Wolke, D, Cappuccio, FP. Nonpharmacological treatments of insomnia for long-term painful conditions: a systematic review and meta-analysis of patient-reported outcomes in randomized controlled trials. Sleep 2015;38:1751–64. Search in Google Scholar

11. Roehrs, TA. Does effective management of sleep disorders improve pain symptoms? Drugs 2009;69:5–11. Search in Google Scholar

12. Jungquist, CR, O’Brien, C, Matteson-Rusby, S, Smith, MT, Pigeon, WR, Xia, Y, et al.. The efficacy of cognitive-behavioral therapy for insomnia in patients with chronic pain. Sleep Med 2010;11:302–9. Search in Google Scholar

13. Sivertsen, B, Lallukka, T, Petrie, KJ, Steingrimsdottir, OA, Stubhaug, A, Nielsen, CS. Sleep and pain sensitivity in adults. Pain 2015;156:1433–9. Search in Google Scholar

14. Andersen, ML, Araujo, P, Frange, C, Tufik, S. Sleep disturbance and pain: a tale of two common problems. Chest 2018;154:1249–59. Search in Google Scholar

15. Eadie, J, van de Water, AT, Lonsdale, C, Tully, MA, van Mechelen, W, Boreham, CA, et al.. Physiotherapy for sleep disturbance in people with chronic low back pain: results of a feasibility randomized controlled trial. Arch Phys Med Rehabil 2013;94:2083–92. Search in Google Scholar

16. Winer, ES, Cervone, D, Bryant, J, McKinney, C, Liu, RT, Nadorff, MR. Distinguishing mediational models and analyses in clinical psychology: atemporal associations do not imply causation. J Clin Psychol 2016;72:947–55. Search in Google Scholar

17. NVK. Act on research ethics review of health research projects; 2018. Available from: Search in Google Scholar

18. Vægter, HB, Christoffersen, LO, Enggaard, TP, Holdgaard, DEM, Lefevre, TN, Eltved, R, et al.. Socio-demographics, pain characteristics, quality of life and treatment values before and after specialized interdisciplinary pain treatment: results from the Danish clinical pain registry (PainData). J Pain Res 2021;14:1215. Search in Google Scholar

19. Vaegter, HB, Graven-Nielsen, T. Pain modulatory phenotypes differentiate subgroups with different clinical and experimental pain sensitivity. Pain 2016;157:1480–8. Search in Google Scholar

20. Vaegter, HB, Handberg, G, Kent, P. Brief psychological screening questions can be useful for ruling out psychological conditions in patients with chronic pain. Clin J Pain 2018;34:113–21. Search in Google Scholar

21. Titze, C, Hasenbring, MI, Kristensen, L, Bendix, L, Vaegter, HB. Patterns of approach to activity in 851 patients with severe chronic pain: translation and preliminary validation of the 9-item avoidance-endurance fast-screen (AEFS) into Danish. Clin J Pain 2021;37:226–36. Search in Google Scholar

22. Kecklund, G, Akerstedt, T. The psychometric properties of the Karolinska sleep questionnaire. J Sleep Res 1992;1:113. Search in Google Scholar

23. Nordin, M, Akerstedt, T, Nordin, S. Psychometric evaluation and normative data for the Karolinska sleep questionnaire. Sleep Biol Rhythm 2013;11:216–26. Search in Google Scholar

24. Clark, AJ, Dich, N, Lange, T, Jennum, P, Hansen, AM, Lund, R, et al.. Impaired sleep and allostatic load: cross-sectional results from the Danish Copenhagen Aging and Midlife Biobank. Sleep Med 2014;15:1571–8. Search in Google Scholar

25. Haefeli, M, Elfering, A. Pain assessment. Eur Spine J 2006;15(1 Suppl):S17–24. Search in Google Scholar

26. Pollard, CA. Preliminary validity study of the pain disability index. Percept Mot Skills 1984;59:974. Search in Google Scholar

27. McKillop, AB, Carroll, LJ, Dick, BD, Battié, MC. Measuring participation in patients with chronic back pain—the 5-item pain disability index. Spine J 2018;18:307–13. Search in Google Scholar

28. Kroenke, K, Spitzer, RL, Williams, JBW. The PHQ-9: validity of a brief depression severity measure. J Gen Intern Med 2001;16:606–13. Search in Google Scholar

29. Löwe, B, Kroenke, K, Herzog, W, Gräfe, K. Measuring depression outcome with a brief self-report instrument: sensitivity to change of the Patient Health Questionnaire (PHQ-9). J Affect Disord 2004;81:61–6. Search in Google Scholar

30. Spitzer, RL, Kroenke, K, Williams, JB, Löwe, B. A brief measure for assessing generalized anxiety disorder: the GAD-7. Arch Intern Med 2006;166:1092–7. Search in Google Scholar

31. Newman, MG, Zuellig, AR, Kachin, KE, Constantino, MJ, Przeworski, A, Erickson, T, et al.. Preliminary reliability and validity of the generalized anxiety disorder questionnaire-IV: a revised self-report diagnostic measure of generalized anxiety disorder. Behav Ther 2002;33:215–33. Search in Google Scholar

32. EuroQol – a new facility for the measurement of health-related quality of life. Health Pol 1990;16:199–208. Search in Google Scholar

33. Pagé, MG, Boyd, K, Ware, MA. Examination of the course of low back pain intensity based on baseline predictors and health care utilization among patients treated in multidisciplinary pain clinics: a Quebec Pain Registry Study. Pain Med 2019;20:564–73. Search in Google Scholar

34. Kamper, SJ, Apeldoorn, AT, Chiarotto, A, Smeets, RJEM, Ostelo, RWJG, Guzman, J, et al.. Multidisciplinary biopsychosocial rehabilitation for chronic low back pain: cochrane systematic review and meta-analysis. BMJ 2015;350:h444. Search in Google Scholar

35. Priebe, JA, Utpadel-Fischler, D, Toelle, TR. Less pain, better sleep? The effect of a multidisciplinary back pain app on sleep quality in individuals suffering from back pain – a secondary analysis of app user data. J Pain Res 2020;13:1121–8. Search in Google Scholar

36. Schrimpf, M, Liegl, G, Boeckle, M, Leitner, A, Geisler, P, Pieh, C. The effect of sleep deprivation on pain perception in healthy subjects: a meta-analysis. Sleep Med 2015;16:1313–20. Search in Google Scholar

37. van Straten, A, van der Zweerde, T, Kleiboer, A, Cuijpers, P, Morin, CM, Lancee, J. Cognitive and behavioral therapies in the treatment of insomnia: a meta-analysis. Sleep Med Rev 2018;38:3–16. Search in Google Scholar

Supplementary Material

The online version of this article offers supplementary material (

Received: 2020-10-06
Accepted: 2021-03-21
Published Online: 2021-04-12
Published in Print: 2021-07-27

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