[Analysis of the relationship between herpes zoster-associated neuralgia and depressive- anxiety states and the mediating role of insomnia].

Objective: To investigate the correlations between pain intensity and insomnia, depression, and anxiety in patients with zoster-associated pain (ZAP), and to examine the mediating role of insomnia in the associations between pain and depression as well as pain and anxiety. Methods: Patients with ZAP who presented to the Department of Pain Medicine, the First Affiliated Hospital of Zhejiang University School of Medicine, from February 2024 to February 2025 were enrolled and divided into acute and chronic phases according to whether the ZAP duration was<30 days. General clinical data were collected. Pain intensity, insomnia, depression, and anxiety were assessed using the Numerical Rating Scale (NRS), Insomnia Severity Index (ISI), 9-item Patient Health Questionnaire (PHQ-9), and 7-item Generalized Anxiety Disorder scale (GAD-7), respectively. Logistic regression was performed to analyze the associations of pain with insomnia, depression and anxiety, and mediation analysis was employed to explore the mediating effect of insomnia on the relationships between pain and depression as well as pain and anxiety. Results: A total of 675 ZAP patients were included, of whom 336 (49.8%) were male, with a median age [M (Q₁, Q₃)] of 67.0 (59.0, 73.0) years. The NRS score for the past 24 hours at admission was (4.3±1.9) points. The prevalence of insomnia was 70.7% (477/675), depression 47.0% (317/675), and anxiety 31.7% (214/675). There were 223 patients in the acute phase and 452 in the chronic phase; no statistically significant differences were found between the two groups in NRS, ISI, PHQ-9, or GAD-7 scores (all P>0.05). Logistic regression analysis demonstrated that, in the overall ZAP cohort, higher NRS scores were significantly associated with higher risks of insomnia, depression, and anxiety, and these associations remained statistically significant after adjusting for important confounders including sex, age, educational level, medical history, and ZAP duration(all P<0.05). Mediation analysis revealed that insomnia partially mediated the relationships between pain and depression [mediation effect β=0.026 (95%CI: 0.018-0.035), proportion mediated=30.6%] and between pain and anxiety [mediation effect β=0.019 (95%CI: 0.014-0.026), proportion mediated=27.6%]. Conclusion: Pain intensity is correlated with the levels of insomnia, depression, and anxiety in ZAP patients, and insomnia exerts a partial mediating effect on the association pathways between pain and depression as well as between pain and anxiety.