Presence of Persistent Pain Common Following ICU Discharge

Patients admitted to the intensive care unit (ICU) may experience persistent pain up to 3 months following discharge, according to a prospective, multicenter study published in Critical Care.  

The study was conducted in 26 hospitals from April 2021 to January 2022, and included 814 adult patients who were admitted to the ICU for at least 48 hours. The patients had a mean age of 57 years, the majority of patients were men (66.5%), and the median length of ICU stay was 6 days. Patients were admitted for major non-thoracic surgery (25.3%), major thoracic surgery (8.2%), non-neurological trauma (15.3%), COVID-19 (9.1%), and sepsis (8.8%). In addition, 11% of patients were receiving chronic treatment with paracetamol or nonsteroidal anti-inflammatory drugs prior to admission.

Follow-up was conducted for 3 months following discharge and the primary outcome was persistent pain rated at or above 3 out of 10, according to the numerical rating scale (NRS). Secondary outcomes included pain intensity, prevalence of potential neuropathic pain, location of pain, analgesic treatment, and risk factors associated with persistent pain.

Of the patients in the analysis, 47.7% and 34.9% of patients presented with persistent pain scores at or more than 3 and at or more than 4 at 3 months, respectively. Patients with persistent pain were more likely to be women (38% vs 29.2%; P =.01), have history of symptoms of anxiety and depression (10.3% vs 6.6%; P =.07), and have greater history of chronic treatment with antidepressants (11.8% vs 6.4%; P =.01).

At the time of discharge, 60.4% of patients reported pain scores greater than or equal to 3. A total of 3.9% of patients reported symptoms consistent with neuropathic pain, with 57.1% of this group also presenting with persistent pain at 3 months.

Patients with persistent pain were more likely to experience non-neurological trauma (22.4% vs 8.7%; P <.001) and undergo orthopedic (14.2% vs 5.4%; P <.001) or spinal (4.9% vs 0.9%; P =.001) surgery.

Risk factors associated with presence of persistent pain were female sex (odds ratio [OR], 1.5; P =.02), history of antidepressant medication use (OR, 2.2; P =.006), being in prone position (OR, 3; P =.003), and intensity of pain at discharge reported as NRS greater than or equal to 3 (OR, 2.4; P <.0001). In particular, patients admitted to the ICU for non-neurological trauma were at greater risk for persistent pain (OR, 3.5; P <.0001).

Of the patients who presented with persistent pain at 3 months, 8.7% had symptoms consistent with neuropathic pain and 11% followed-up with a pain specialist.

This study was limited by inability to perform face-to-face interviews with patients to evaluate pain symptoms. In addition, the time of day that pain assessments were performed was not standardized. Finally, the screening tool used to assess neuropathic pain symptoms was the ID-Pain score, which was not the most specific measure.

The researchers concluded, “Persistent pain could be a common health problem after critical illness care. Given the major consequences on patient quality of life, the

social implications and health-care costs, it appears to be important to design innovative interventions to minimize the consequences of pain after critical care illness.”