Abstract
BACKGROUND: Frontline nurses at designated hospitals endured psychological distress and sleep problems during the COVID-19 pandemic. However, the long-term effects have not yet been thoroughly investigated. This study examines their sleep status and related factors two years later to inform staffing and mental health support. METHODS: A cross-sectional study was conducted at a large tertiary COVID-19-designated hospital in Wuhan, China, in 2022. Using convenience sampling, we recruited 552 clinical nurses. Participants completed the Insomnia Severity Index (ISI), Perceived Stress Scale (PSS), and Maslach Burnout Inventory-Human Services Survey (MBI-HSS). Quantile regression was used to evaluate the relationship between variables and insomnia. The findings were interpreted through the lens of the 3P model of insomnia in this cohort. RESULTS: The median ISI-7 score was 5.00 (7.00), and 6.88% of nurses had moderate-to-severe insomnia. According to the quantile regression results, female gender, the nucleic acid testing site and self-reported COVID-19-related posttraumatic stress symptoms, which were interpreted as predisposing factors, were associated with insomnia at the 10th and 10th-50th quantiles, respectively. Average weekly working hours (> 60 h and 41-60 h) attributed to precipitating factors were associated with insomnia at the 10th and 75th quantiles. Emotional exhaustion and perceived stress were associated with insomnia across all quantiles, while personal accomplishment was associated with it at the 75th quantile, aligning with the model’s perpetuating factors. CONCLUSIONS: Insomnia remains a health concern among nurses two years after the outbreak. The 3P model associates insomnia with vulnerabilities, traumatic exposure, and ongoing occupational stress. Multi-level, theory-based interventions should target these factors to support nurses’ well-being and reinforce healthcare system resilience. CLINICAL TRIAL NUMBER: Not applicable. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12912-026-04498-y.