Occurrence and Risk Factors of Chronic Pain After Critical Illness.

Objectives: Occurrence, risk factors, and impact on daily life of chronic pain after critical illness have not been systematically studied. Design: Cohort study. Setting: A tertiary ICU in The Netherlands. Patients: We surveyed patients who had been discharged from our ICU between 2013 and 2016. Three cohorts were defined as follows: 1) ICU survivors; 2) one-year survivors reporting newly-acquired chronic pain; and (3) one-year survivors with pain who lived within 50 km from the study hospital. In cohort 1, we estimated the prevalence of new chronic pain 1 year after ICU discharge and constructed a prediction model for its occurrence incorporating three outcomes: death during follow-up, surviving without new pain, and surviving with newly-acquired pain. In cohort 2, we determined clinical features of pain and its impact on daily life. In cohort 3, we assessed the presence of neuropathic characteristics of pain. Interventions: None. Measurements and Main Results: The three cohorts contained 1,842, 160, and 42 patients, respectively. Estimated occurrence of new chronic pain was 17.7% (95% CI, 15.8-19.8%; n = 242) in 1-year survivors (n = 1,368). Median pain intensity on the numeric rating scale was 4 (interquartile range, 2-6) in the week before survey response, with impact being most evident on activities of daily living, social activities, and mobility. Neuropathic pain features were present in 50% (95% CI, 37-68%) of affected subjects. Among nine predictor variables included in a multinomial model, only female gender and days in ICU with hyperinflammation were associated with pain. Conclusions: Newly-acquired chronic pain is a frequent consequence of critical illness, and its impact on daily life of affected patients is substantial.