Associates of Insomnia in People with Chronic Spinal Pain: A Systematic Review and Meta-Analysis

Abstract

Insomnia is a major problem in the chronic spinal pain (CSP) population and has a negative impact on health and well-being. While insomnia is commonly reported, underlying mechanisms explaining the relation between sleep and pain are still not fully understood. Additionally, no reviews regarding the prevention of insomnia and/or associated factors in people with CSP are currently available. To gain a better understanding of the occurrence of insomnia and associated factors in this population, we conducted a systematic review of the literature exploring associates for insomnia in people with CSP in PubMed, Web of Science and Embase. Three independent reviewers extracted the data and performed the quality assessment. A meta-analysis was conducted for every potential associate presented in at least two studies. A total of 13 studies were found eligible, which together identified 25 different potential associates of insomnia in 24,817 people with CSP. Twelve studies had a cross-sectional design. Moderate-quality evidence showed a significantly higher rate for insomnia when one of the following factors was present: high pain intensity, anxiety and depression. Low-quality evidence showed increased odds for insomnia when one of the following factors was present: female sex, performing no professional activities and physical/musculoskeletal comorbidities. Higher healthcare use was also significantly related to the presence of insomnia. One study showed a strong association between high levels of pain catastrophizing and insomnia in people with chronic neck pain. Last, reduced odds for insomnia were found in physically active people with chronic low back pain compared to inactive people with chronic low back pain. This review provides an overview of the available literature regarding potential associates of insomnia in people with CSP. Several significant associates of insomnia were identified. These findings can be helpful to gain a better understanding of the characteristics and potential origin of insomnia in people witch CSP, to identify people with CSP who are (less) likely to have insomnia and to determine directions of future research in this area.

Keywords: associates; back pain; lifestyle factors; neck pain; psychosocial factors; sleep–wake disorders; socio-demographic factors; systematic review.

Conflict of interest statement

The authors declare no conflict of interest.

Figures

Figure 1

Flow diagram illustrating the study selection process.

Figure 2

Forest plots showing odds ratios of several potential associated factors with insomnia in people with chronic spinal pain. A meta-analysis is conducted for the factors sex (n = 12,722), age (n = 1626), body mass index (n = 10,886), physical activity (n = 10,796), professional activity (n = 4405), comorbidities (n = 1626), pain intensity (n = 443), depression (n = 443) and anxiety (n = 443). Every blue box represents the observed odds ratio of the corresponding study. The size of every blue box is proportional to the weight of the study in the meta-analysis. The confidence intervals are represented by the horizontal lines through the blue boxes. The pooled odds ratio is represented by a black diamond, with the lateral tips of the diamond representing the associated confidence interval. Abbreviations: CNP, chronic neck pain; CLBP, chronic low back pain. a Aili et al. defined younger participants as people < 45 years [46]. b Kim et al. defined younger participants as people < 65 years [39]. c Blay et al. dichotomized physical activity in Yes/No but did not provide any detail about the level of physical activity used as a cut-off [36]. d Mork et al. defined physically active people as people performing more than one (accumulated) hour of exercise per week [41]. e Aili et al. defined performing no professional activity as “Unemployed for the last year/not working” [46]. f Blay at al. dichotomized professional activity as active/non-active but did not provide any further details [36]. g Kim et al. defined a high pain score as NRS ≥ 7 [39]. h Wang et al. defined a high pain score as VAS ≥ 7 [45]. i Kim et al. defined depression as a score of at least 8 on the HADS-D [39]. j Participants in the study of Wang et al. were screened by a board-certified psychiatrist for the presence of a current major depressive episode [45]. k Kim et al. defined depression as a score of at least 8 on the HADS-A [39]. l Participants in the study of Wang et al. were screened by a board-certified psychiatrist for the presence of any anxiety disorders [45].

Figure 2

Forest plots showing odds ratios of several potential associated factors with insomnia in people with chronic spinal pain. A meta-analysis is conducted for the factors sex (n = 12,722), age (n = 1626), body mass index (n = 10,886), physical activity (n = 10,796), professional activity (n = 4405), comorbidities (n = 1626), pain intensity (n = 443), depression (n = 443) and anxiety (n = 443). Every blue box represents the observed odds ratio of the corresponding study. The size of every blue box is proportional to the weight of the study in the meta-analysis. The confidence intervals are represented by the horizontal lines through the blue boxes. The pooled odds ratio is represented by a black diamond, with the lateral tips of the diamond representing the associated confidence interval. Abbreviations: CNP, chronic neck pain; CLBP, chronic low back pain. a Aili et al. defined younger participants as people < 45 years [46]. b Kim et al. defined younger participants as people < 65 years [39]. c Blay et al. dichotomized physical activity in Yes/No but did not provide any detail about the level of physical activity used as a cut-off [36]. d Mork et al. defined physically active people as people performing more than one (accumulated) hour of exercise per week [41]. e Aili et al. defined performing no professional activity as “Unemployed for the last year/not working” [46]. f Blay at al. dichotomized professional activity as active/non-active but did not provide any further details [36]. g Kim et al. defined a high pain score as NRS ≥ 7 [39]. h Wang et al. defined a high pain score as VAS ≥ 7 [45]. i Kim et al. defined depression as a score of at least 8 on the HADS-D [39]. j Participants in the study of Wang et al. were screened by a board-certified psychiatrist for the presence of a current major depressive episode [45]. k Kim et al. defined depression as a score of at least 8 on the HADS-A [39]. l Participants in the study of Wang et al. were screened by a board-certified psychiatrist for the presence of any anxiety disorders [45].