Incidence and Associated Factors for Chronic Pain After ICU Discharge: A Prospective Study

BACKGROUND: Survivors of critical illness are at high risk for developing chronic pain. However, evidence regarding new-onset chronic pain in this specific population remains limited in China. AIMS: This study aimed to investigate the incidence of chronic pain among Chinese intensive care unit (ICU) survivors at 3 months after discharge and to identify associated factors. STUDY DESIGN: This was a prospective study. The participants were adult ICU survivors from a mixed ICU of a tertiary hospital in Zhejiang, China. The Brief Pain Inventory (BPI) was used to assess pain at 3 months after ICU discharge. Multivariable binary logistic regression was performed to identify factors independently associated with chronic pain. RESULTS: Among 328 ICU survivors, 109 (33.2%) reported new-onset chronic pain, including 64 of 109 (58.7%) with mild pain (BPI average pain score 1-3), 42 of 109 (38.5%) with moderate pain (BPI average pain score 4-6) and 3 of 109 (2.8%) with severe pain (BPI average pain score 7-10). The shoulder was the most frequently reported pain site (46 of 109, 42.2%), and normal work was the daily domain most affected by pain. Multivariable analysis showed that pre-existing chronic pain (OR = 4.77, 95% CI: 2.02-11.30, p < 0.001), days with mechanical ventilation (OR = 1.27, 95% CI: 1.17-1.37, p < 0.001), and days with hyperinflammation (OR = 1.34, 95% CI: 1.18-1.53, p < 0.001) were independently associated with the development of new-onset chronic pain. Among 286 patients without pre-existing chronic pain, 79 (27.6%) developed new-onset chronic pain; mechanical ventilation duration and hyperinflammation remained independently associated with this outcome. CONCLUSIONS: Approximately one-third of ICU survivors experience chronic pain, with 41.3% reporting moderate-to-severe pain that interfered with daily functioning. These findings highlight the importance of systematic pain assessment and targeted follow-up after ICU discharge. RELEVANCE TO CLINICAL PRACTICE: Post-ICU follow-up should include systematic assessment of chronic pain and pain-related functional impairment alongside other PICS domains, including psychological distress, cognitive dysfunction and physical impairments, to ensure holistic, patient-centred recovery after critical illness.