The Role of Pain in Relation to Fibromyalgia and Insomnia

There’s been research that’s displayed a bidirectional relationship between insomnia and anxiety, associations between pain and insomnia, as well as associations between pain and anxiety.

While there hasn’t been research that explored the role of pain related to disability, insomnia and anxiety, a new study featured at the Associated Professional Sleep Societies (SLEEP) 2022 Annual Meeting evaluated the moderating impact of self-reported pain related to disability on the relationship between subjective sleep variables and anxiety scores in adults with fibromyalgia and insomnia.

Adults with fibromyalgia live with widespread pain due to the chronic condition. As much as 90% of patients with fibromyalgia have comorbid sleep disorders like insomnia, with up to 64% experiencing comorbid anxiety disorders.

Sleep Variables and Moderation Analyses

Alan Guandique, Neetu Nair, and Christina McCrae, from the University of Missouri, conducted a study that included 219 adults with fibromyalgia and insomnia. The majority (92.8%) were women.

Over the course of 14 days, the participating adults completed daily sleep diaries, the Pain Disability Index (PDI), and the State-Trait Anxiety Inventory Form Y-1 (STAI-Y1) as part of the baseline for a larger randomized clinical trial.

Moderation analyses included STAI-Y1 as the dependent variable, sleep variables averaged over 14 days as independent variables, the PDI served as the moderator, with age and years of education as covariates. Sleep variables included sleep onset latency, wake after sleep onset, total sleep time, and sleep efficiency.

Pain, Anxiety and Falling Asleep

Investigators found that higher levels of perceived pain related disability and greater difficulty falling asleep was associated with increased anxiety levels in adults with fibromyalgia and insomnia. They noted that the relationship between difficulty falling asleep and anxiety levels may be invesersed at lower levels of pain related disability.

“PDI moderated the relationship between sleep onset latency and STAI-Y1 (B=0.0052, SE=0.0019, p=0.01, R2=0.04),” investigators wrote. “At high PDI scores (but not average), higher sleep onset latency was associated with higher STAI-Y1 scores (B=0.0748, SE=0.0310, p=0.02). At low PDI scores, higher SOL was associated with lower STAI-Y1 scores (B=-0.0844, SE=0.0453, p=0.06; trend).”

“This points to a possible complex interplay between sleep difficulties, pain related disabilities and anxiety in the fibromyalgia and insomnia population,” investigators concluded. “Future research is warranted to examine potential causal relationships between pain, sleep, and anxiety.”