Introduction
Dear Editor:
Individuals with chronic low back pain (cLBP) show increased pain sensitivity and reduced physical functioning compared with healthy, pain-free adults.1 Patients with cLBP also report greater sleep disturbance,2 and sleep disturbance longitudinally predicts worse pain and impaired functioning.3 Opioids may be prescribed to help manage pain, and indeed, opioids have been shown to provide short-term pain relief, although these effects are modest and there is little to no impact on functional disability.4 Whereas some research suggests that opioids disrupt sleep patterns and contribute to poor sleep,5 other research indicates that opioids improve sleep, although observed effects are small.6
Less is known about how sleep disturbance and opioid use interact to impact pain and functioning. One study explored the interaction between sleep and opioid use on pain severity and pain interference among patients with chronic pain but did not find evidence of interactive effects.7 Importantly, that study excluded patients on long-term opioids, thereby excluding a subpopulation of patients. Additionally, patients in their study received medication management by a pharmacist, which is not standard in routine practice. Thus, more research is needed to understand the interactive effect of sleep disturbance and opioid use, specifically among patients with cLBP. In the present study, we examined associations among sleep disturbance, opioid use, physical functioning, and pain outcomes among patients with cLBP. We then explored whether opioids moderated the associations of sleep disturbance with physical functioning or pain outcomes.
Methods
Participants were recruited through the Partners Healthcare Clinical Trials website, email, bulletin boards, the Internet, and electronic medical record databases from Brigham and Women’s Hospital and Massachusetts General Hospital from 2013 to 2020. Eligibility criteria included self-reported cLBP of ≥3 months’ duration, average pain rating ≥4/10, and no comorbid medical/pain conditions (eg, bipolar disorder, cancer). Participants provided informed consent, and the Partners Healthcare Institutional Review Board approved all study procedures.
The Patient-Reported Outcomes Measurement Information System (PROMIS) short forms8 were used to measure pain severity, pain interference, physical functioning, and sleep disturbance. Participants also completed PROMIS measures of depression, anxiety, and fatigue. Scores were rescaled with the PROMIS score conversion table and converted to standardized T-scores (mean = 50, SD = 10).8 Participants also reported whether they used opioid medications for their back pain (no/yes) and provided demographic information.
Results
Participants (n = 213) were 42.8 years (SD = 13.3; range: 18–65 years) of age, and 58% were female. Participants were White (75%), African American / Black (12%), Asian (4%), American Indian / Alaska Native (0.5%), Native Hawaiian or Pacific Islander (0.5%), more than one race (4%), and 4% preferred not to answer. The majority of participants were non-Hispanic (90%). Of all participants, 87% provided their body mass index and had an average body mass index of 26.7 (SD = 5.4). Over the prior week, 57% of participants had used alcohol, 29% reported not using alcohol, and 14% did not report their alcohol use. Most participants were not current smokers (81%), 6% were current smokers, and 13% did not report their smoker status.
Pearson correlations and t tests were conducted to examine associations among sleep disturbance, physical functioning, pain-related outcomes, opioid status (user vs nonuser), and psychological symptoms (Table 1). Sleep disturbance was correlated with worse pain severity, greater pain interference, and impaired physical functioning. Patients taking opioids reported greater sleep disturbance, worse pain severity, and greater pain interference. Opioid use was not related to physical functioning.
Table 1.
Participant characteristics and associations of sleep, pain, physical function, opioid use, and psychological symptoms.
| Mean ± SD or n (%) | Sleep disturbance | Pain severity | Pain interference | Physical function | |
|---|---|---|---|---|---|
| Sleep disturbance | 52.2 ± 8.2 | – | 0.39** | 0.44** | –0.39** |
| Pain severity | 5.6 ± 1.7 | – | – | 0.57** | –0.48** |
| Pain interference | 59.7 ± 6.3 | – | – | – | –0.65** |
| Physical function | 38.1 ± 4.5 | – | – | – | – |
| Opioid use | |||||
| No | 162 (76) | 51.4 ± 8.2a | 5.5 ± 1.7a | 58.6 ± 5.9a | 38.3 ± 4.1a |
| Yes | 51 (24) | 54.9 ± 7.7b | 6.0 ± 1.7b | 63.0 ± 6.2b | 37.4 ± 5.7a |
| Anxiety | 50.6 ± 8.7 | 0.24** | 0.18* | 0.25** | –0.12 |
| Depression | 47.5 ± 8.3 | 0.30** | 0.24** | 0.37** | –0.18* |
| Fatigue | 52.3 ± 9.4 | 0.46** | 0.25** | 0.51** | –0.28** |
n = 213.
Means are reported as PROMIS T-scores (range: 0–100), except for pain severity (range: 0–10).
Pearson correlations for continuous variables,
P < .01,
P < .001.
t tests for categorical variables. For each categorical variable, means with different subscripts (a and b) indicate that the groups were significantly different from each other (P < .05).
To explore the interactive effects of sleep disturbance and opioids on functioning and pain, separate bootstrapped moderation analyses were conducted with the PROCESS macro for SPSS. Because cLBP is highly comorbid with psychological symptoms, depression, anxiety, and fatigue were included as covariates. A post hoc power analysis indicated that a sample of 213 participants could detect a small- to medium-sized effect (f2 = 0.04) of an interaction, assuming power = 0.80 and α = 0.05.
Opioids significantly moderated the association of sleep disturbance with physical functioning (b = –0.22, 95% CI–0.39 to –0.05, P = .011) and pain interference (b = 0.23, 95% CI 0.02 to 0.44, P = .031) (Figure 1). Among patients taking opioids, greater sleep disturbance was associated with worse physical functioning (b = –0.36, 95% CI –0.51 to –0.20, P < .001) and greater pain interference (b = 0.35, 95% CI 0.16 to 0.54, P < .001). Opioid status did not significantly moderate the association of sleep disturbance with pain severity (P = .10).
Figure 1.
The interactive effects of sleep disturbance and opioid use on (A) physical function (higher scores = better function), (B) pain-related interference (higher scores = greater pain interference), and (C) pain severity (higher scores = worse pain), while controlling for psychological symptoms (ie, depression, anxiety, fatigue).
Discussion
Patients taking opioids to help manage their back pain reported significantly worse sleep disturbance, providing further evidence that opioids could have a negative impact on sleep.5 Opioid status significantly moderated the association between sleep disturbance and function-related outcomes, suggesting that among patients with cLBP, the relationships of sleep disturbance with functional disability and pain interference, but not severity of pain, might be exacerbated by opioid use. These findings differ from one prior study, perhaps because of a difference in sample characteristics.7 Our findings suggest that the combined deleterious effects of opioids and sleep quality might be more relevant for understanding functional outcomes than for understanding the severity of pain experienced. Cognitive behavioral therapy for insomnia has been shown to effectively improve sleep among patients with chronic pain9 and might also improve pain outcomes. Notably, cognitive behavioral therapy for insomnia leads to larger improvements in pain-related functioning than in pain severity.10
Several limitations of our work should be considered. We did not collect comprehensive assessments of opioid use, sleep disturbance, or participants’ medical history. Future research should capture the nuances of opioid use (eg, chronicity of use, high dose vs low dose) and sleep disturbance (eg, insomnia, sleep apnea) to potentially identify which symptoms could be most beneficial to target in interventions. The data were cross-sectional, and future studies should use prospective, longitudinal study designs. Additionally, the majority of participants were non-Hispanic White, and participants were excluded if they had comorbid medical/pain conditions, which could affect the generalizability of our findings.
Overall, our findings highlight the importance of assessing the effects of sleep disturbance on functional outcomes in the context of opioid medications. These findings have important clinical implications, suggesting that interventions targeting sleep quality could be especially beneficial for pain management and functional ability among patients with cLBP taking opioid medications.
Contributor Information
Jenna M Wilson, Department of Anesthesiology, Perioperative, and Pain Medicine, Brigham and Women’s Hospital, Boston, MA 02115, United States.
JiHee Yoon, Department of Anesthesiology, Perioperative, and Pain Medicine, Brigham and Women’s Hospital, Boston, MA 02115, United States.
Kristin L Schreiber, Department of Anesthesiology, Perioperative, and Pain Medicine, Brigham and Women’s Hospital, Boston, MA 02115, United States.
Robert R Edwards, Department of Anesthesiology, Perioperative, and Pain Medicine, Brigham and Women’s Hospital, Boston, MA 02115, United States.
Christine B Sieberg, Biobehavioral, Pain Innovations Lab, Department of Psychiatry and Behavioral Sciences, Boston Children's Hospital, Boston, MA 02115, United States; Pain and Affective Neuroscience Center, Department of Anesthesiology, Critical Care, and Pain Medicine, Boston Children's Hospital, Boston, MA 02115, United States; Department of Psychiatry, Harvard Medical School, Boston, MA 02215, United States.
Samantha M Meints, Department of Anesthesiology, Perioperative, and Pain Medicine, Brigham and Women’s Hospital, Boston, MA 02115, United States.
Funding
This study was funded by the National Institutes of Health (K23AR077088 [S.M.M.], K23GM123372 [C.B.S.], K23GM123372-04S1 [C.B.S.], K24NS126570 [R.R.E.]).
Conflicts of interest: We have no known conflict of interest to disclose.
References
- 1. Meints SM, Mawla I, Napadow V, et al. The relationship between catastrophizing and altered pain sensitivity in patients with chronic low back pain. Pain. 2019;160(4):833-843. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 2. Kelly GA, Blake C, Power CK, et al. The association between chronic low back pain and sleep: a systematic review. Clin J Pain. 2011;27(2):169-181. [DOI] [PubMed] [Google Scholar]
- 3. Finan PH, Goodin BR, Smith MT.. The association of sleep and pain: an update and a path forward. J Pain. 2013;14(12):1539-1552. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 4. Balanaser M, Carley M, Baron R, et al. Opioids compared with placebo or other treatments for chronic low back pain: an update of the Cochrane Review. Spine. 2023;164(2):230-251. [Google Scholar]
- 5. Tripathi R, Rao R, Dhawan A, et al. Opioids and sleep—a review of literature. Sleep Med. 2020;67:269-275. [DOI] [PubMed] [Google Scholar]
- 6. Puterflam JM, Comis JJ, Lan Q, et al. The short-term effects of opioid and non-opioid pharmacotherapies on sleep in people with chronic low back pain: a systematic review and meta-analysis of randomized controlled trials. Sleep Med Rev. 2022;65:101672. [DOI] [PubMed] [Google Scholar]
- 7. Koffel E, Kats AM, Kroenke K, et al. Sleep disturbance predicts less improvement in pain outcomes: secondary analysis of the SPACE randomized clinical trial. Pain Med. 2020;21(6):1162-1167. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 8. Cella D, Riley W, Stone A, et al. ; PROMIS Cooperative Group. The Patient-Reported Outcomes Measurement Information System (PROMIS) developed and tested its first wave of adult self-reported health outcome item banks: 2005–2008. J Clin Epidemiol. 2010;63(11):1179-1194. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 9. Koffel E, McCurry SM, Smith MT, et al. Improving pain and sleep in middle-aged and older adults: the promise of behavioral sleep interventions. Pain. 2019;160(3):529-534. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 10. Finan PH, Buenaver LF, Coryell VT, et al. Cognitive-behavioral therapy for comorbid insomnia and chronic pain. Sleep Med Clin. 2014;9(2):261-274. [DOI] [PMC free article] [PubMed] [Google Scholar]