Poor Sleep Quality and Mood Disorders: Risk Factors of Increasing Chronic Pain in Patients with Insomnia

The aim of this study was to examine the prevalence of chronic pain and its risk factors in patients with insomnia.

We consecutively enrolled patients with chronic insomnia from Sleep Medicine Center in West China Hospital between May 2019 and February 2021. All patients were divided into two groups according to comorbid chronic pain or not. We used subjective questionnaires to assess sleep, daytime sleepiness, mood symptoms, and the characteristics and intensity of pain. Objective sleep quality was measured by polysomnography. The logistic regression analyses were used to identify the risk factors of chronic pain.

Among 358 patients with chronic insomnia, 48.9% had chronic pain. These patients had significantly higher scores in Hamilton Rating Scale for Anxiety (HAMA), Hamilton Rating Scale for Depression (HAMD), Visual Analog Scale (VAS) and Short-Form McGill Pain Questionnaire (SF-MPQ) (all PS < 0.001) compared to those without chronic pain. After controlling for the confounding factors, higher HAMA scores adjusted odds ratio = 1.083, 95% CI 1.033-1.135, P = 0.001), higher HAMD scores (adjusted odds ratio = 1.109, 95% CI 1.058-1.163, P < 0.001) and shorter N3 sleep duration (adjusted odds ratio = 0.969, 95% CI 0.940-0.999, P = 0.041) were significantly associated with an increased risk of chronic pain. Multiple linear regression analyses showed that higher scores in Pittsburgh Sleep Quality Index (PSQI) (β = 0.108, 95% CI 0.026-0.191, P = 0.010), HAMA (β = 0.085, 95% CI 0.043-0.127, P < 0.001) and HAMD (β = 0.141, 95% CI 0.093-0.188, P < 0.001) were positively related to pain intensity.

Nearly half of patients with insomnia are comorbid with chronic pain. Poor subjective and objective sleep quality, as well as the anxious and depressive symptoms, are risk factors of chronic pain.