Evidence Linking Sleep to Improved Lower Back Pain Outcomes Is Weak, More Studies Needed

Lower back pain (LBP) and lack of improvement in LBP may be linked to individual sleep quality, according to a study recently published in Sleep; however, more comprehensive studies are required to confirm these associations.

Man Holding Lower Back | image credit: innervisionpro - stock.adobe.com

LBP is one of the main global drivers of years lived with disability and can contribute to substantial health care costs. As the authors of the present study note, LBP affects over 70% of adults, the prevalence of LBP is trending upwards, and pain in the lower back and neck contributed to over $134 billion in average costs as recently as 2016.

Sleep issues are heavily documented in individuals experiencing LBP. The authors point to a systematic review that revealed almost 75% of individuals enduring chronic back pain experience poor quality of sleep compared with nearly 25% of individuals who did not have pain. Prior reports have also linked less sleep and interrupted sleep, among other sleep factors, to musculoskeletal pain, increased inflammation, and pain thresholds. Additionally, other reviews have drawn connections between improved pain outcomes and interventions designed to improve sleep quality.

While some studies point to these associations, the literature on this subject is inconsistent and conflicting. To expand on this knowledge and seek out more concrete conclusions, researchers conducted a systematic literature review of randomized controlled trials and prospective cohort studies to investigate the degree of association between outcomes in adults with LBP and their sleep quality.

The review included 14 studies from 16 records published between 2014 and 2022. These studies spanned multiple countries throughout Europe, as well as the US, Japan, Brazil, Iran, and Australia. Participants in these records had a median age of 46 years. Measured factors concerned sleep quality, sleep quantity, sleepiness during the day, and insomnia. Outcomes of interest were pain intensity, experienced disability, and patient recovery.

In 3 studies that evaluated the baseline sleep quality of 1711 participants with pain intensity outcomes, 2 found positive correlations between sleep quality and pain intensity whereas the remaining study found no such associations. The authors of the current study believed this research produced very weak evidence.

Four studies assessed the relationship between baseline sleep quality and disability in 849 participants. One of these studies did not find any associations, another study was only able to have its raw data extracted (meaning how many individuals with poor and good sleep were in the unimproved or improved group), and the 2 remaining studies revealed a positive association between sleep and disability at 3- and 6-month follow-up. Again, the researchers found these results to be weak evidence suggesting sleep is a prognostic factor in disability.

Five studies included data from 13,294 individuals regarding sleep and LBP recovery. Three of these studies observed a positive correlation between participant recovery and sleep. Two studies did not find any associations at 6-month nor 156-month follow-up. In a similar trend, this group was studied was cited as low-quality.

The authors encountered many limitations, including high risks of study-bias due to poor reporting, low response rates, and inadequate sleep measures. Additionally, they had to calculate the odds and rate ratios in many of their observed studies. While they did find evidence suggesting an association between better sleep quality and improved LBP outcomes, the studies available to them were not seen as providing high-quality, discernable conclusions on this relationship. As they conclude, the authors do recommend that clinicians take up interest in sleep-targeted interventions as an avenue for managing pain in their patients since positive associations were found relating to sleep quality and pain, recovery, and disability. However, they express the need for future studies to identify potential cofounders, better define sleep parameters, and implement improved reporting methods to come to firmer conclusions on this topic.

Reference

Silva S, Hayden JA, Mendes G, Verhagen A, Pinto RZ, Silva A. Sleep as a prognostic factor in low back pain: a systematic review of prospective cohort studies and secondary analyses of randomized controlled trials. Sleep. Published online February 1, 2024. doi:10.1093/sleep/zsae023