The Association of Severe Pain Experienced in the PICU and Health-Related Quality of Life Post-Discharge

BACKGROUND: A decline in health-related quality of life (HRQL) is common after pediatric intensive care unit (PICU) admission. There are few known modifiable risk factors during PICU admission for a clinically significant decline in HRQL. Chronic pain is known to be associated with low HRQL. We hypothesized that the duration of severe pain during PICU admission is associated with low HRQL postdischarge.

METHODS: This was a retrospective cohort study of 546 patients <18 years of age admitted to a tertiary PICU in a free-standing children’s hospital with follow-up data on HRQL post-discharge. Pain scores were abstracted from the electronic medical record and were documented every two hours during PICU admission. The primary exposure was days of severe pain, “severe” defined as days with >25% of pain scores at a level of 7 or above. The primary outcome was HRQL score at the time of follow-up at 4-6 weeks following hospital discharge. We compared patient demographic, baseline function and health, illness, and treatment characteristics for patients with zero days of severe pain in the PICU to patientswith one or more days of severe pain in the PICU with chi-square tests and Fisher exact tests (for comparisons involving < 30 in a category) for categorical variables and Student’s t-test for continuous variables. We used multivariable linear regression models to evaluate a possible association between days of severe pain and HRQL post-discharge adjusting for age, baseline HRQL score, baseline cognitive function as defined by the PCPC, illness severity as defined by days with PELOD score indicating dysfunction in two or more organ systems, and PICU LOS. We did a stratified analysis of HRQL score for patients who responded with the PedsQL^TM as opposed to the FS-II R by primary diagnosis category (surgical vs medical).

RESULTS: Relative to children without at least one day of severe pain, those who did experience pain were older ( 7.4 years vs 5.8 years), less likely to have cognitive dysfunction (10.8% versus 24.1%), more likely to be admitted for a surgical diagnosis (63.1% versus 46.4%), had a longer hospital length of stay (8.6 days vs. 6.0 days), more days of agitation (1.8 days vs. 0.9 days), and received more opiates in the PICU (2.7 mg/kg of morphine vs. 1.4 mg/kg of morphine). HRQL scores post-discharge declined in a linear pattern for each increasing day of severe pain. For children with the same baseline HRQL, each day of severe pain experienced in the PICU was associated with a lower post-discharge HRQL score by 3.9 points (95% CI -6.53 to -1.27). In multivariable linear regression, each day of pain was associated with a lower post-discharge HRQL score by 3.4 points (95% CI -6.04 to -0.73), after adjustment for baseline HRQL score, age, baseline cognitive function, days with multi-organ dysfunction, and PICU LOS. This association was stronger among surgical patients than among medical patients.

CONCLUSIONS: Children admitted to the PICU who experience relatively more severe pain have lower HRQL post-discharge, particularly among children who had undergone surgery.