Evaluation of Measures of Pain Outcomes Among Survivors of Critical Illness

The single pain and discomfort question contained within the EuroQOL 5-dimension, 5-level (EQ-5D-5L) assessment was found to correlate with the pain interference and severity components of the Brief Pain Inventory (BPI) among survivors of acute respiratory failure, according to the results of a study published in BMJ Open Respiratory Research. Use of this single question may therefore serve as an easy and efficient tool for assessing pain in patients who survive critical illness.

According to the study authors, “Up to 66% of those who survive critical illness will develop chronic pain resulting in wide-ranging functional impact, affecting quality of life, activities of daily living and return to work.”

A team of investigators from Scotland therefore conducted this multicenter, prospective cohort study by recruiting 280 patients at 9 hospitals between 2016 and 2020. Patients who survived acute respiratory failure and either participated in the Intensive care Syndrome: Promoting Independence and Return to Employment (InS:PIRE) intervention (n=172) or received usual care (n=108) were evaluated with the EQ-5D-5L and BPI assessments. Correlations between pain outcomes in the 2 instruments were evaluated. The InS:PIRE cohort completed the questionnaires at baseline, 3 months, and 12 months; the usual care cohort completed the questionnaires at 12 months only.

Median ages of patients in the InS:PIRE and control cohorts were 58.4 (interquartile range [IQR], 50.6-66.2) and 63.8 (IQR, 49.7-71.4) years (P =.02), 57.0% and 56.5% were men, and 42.4% and 28.7% were in the lowest quintile of the Scottish government’s standard approach to identifying deprivation (P =.03), respectively. Median lengths of stay in the intensive care unit were 10 (IQR, 6-17) and 5 (IQR, 3-10) days (P <.01), median durations of time spent on advanced respiratory support were 6 (IQR, 3-13) and 4 (IQR, 2-9) days (P =.01), and median durations of hospitalization were 30 (IQR, 16-50) and 19 (IQR, 12-36) days (P <.01), respectively.

At the 3 assessments among the InS:PIRE group and the 1 assessment among the usual care cohort, the single pain and discomfort question on the EQ-5D-5L was found to significantly correlate with BPI pain severity (correlation coefficient [CC] range, 0.73-0.8; P <.01) and pain interference (CC range, 0.71-0.83; P <.01).

Stratified by each incremental increase in EQ-5D-5L pain and discomfort score, change in BPI severity score was associated with 2 to 3 (associated change, 2.38; P <.01) and 3 to 4 (associated change, 1.75; P =.01) increments at baseline; 1 to 2 (associated change, 2; P =.01), 2 to 3 (associated change, 2.5; P =.01), and 3 to 4 (associated change, 1.88; P =.04) increments at 3 months; and 1 to 2 increments at 12 months (associated change, 2.75; P =.01) among the InS:PIRE group and with 2 to 3 (associated change, 3.00; P <.01) and 3-4 (associated change, 3.25; P =.02) increments among the usual care group.

Similar trends were observed in the subgroup analyses among only patients with pre-existing chronic pain or mental health diagnoses.

Limitations of this study include the lack of multiple assessments among participants in the control group, as well as some patients self-administering the questionnaires or answering questions over the telephone.

Study authors conclude, “The EQ-5D-5L pain and discomfort question, which was proposed for inclusion in the core outcome sets for survivors of acute respiratory failure to evaluate pain, appears to correlate well with an established, specific pain measurement tool in 2 different cohorts of critical care survivors. More research is required to fully understand the extent of pain in survivors of critical illness, alongside interventional research examining potential mechanisms and effective treatment strategies.”