Evaluating the Reliability of Caregiver Report for the Functional Status Scale: A Pilot Study

Introduction: Fewer children are dying from critical illness; however, more are surviving with new deficits. The Functional Status Scale (FSS) was created to quickly and accurately quantify dysfunction level across domains of mental, sensory, communication, motor, feeding, and respiratory. This measure was validated for medical professionals, but caregiver input is lacking. Caregivers provide different perspectives especially regarding baseline status and the ability to monitor changes over time. This pilot study sought to be a first step to compare FSS scores between professionals and caregivers. Methods: Secondary analysis of data from an ongoing quality improvement program within a 36-bed pediatric intensive care unit (PICU) at a tertiary care children’s hospital. Children under 18 admitted to the PICU with new neurologic conditions were eligible. FSS was completed by the child’s primary caregiver and a study team member at three timepoints: baseline, PICU discharge, and follow-up. Interrater reliability between professional and caregiver FSS scores was evaluated using intraclass correlation coefficients (ICCs) for the total sample and stratified by chronic condition status at PICU admission and timepoint using a two-way mixed effects model. Results: Acceptable level of reliability between professional and caregiver FSS scores was found when all timepoints were analyzed together in a single model (ICC=0.46). ICC was acceptable for chronically ill children (0.56), but poor for children without chronic illness (0.30). The nurse coordinator had the highest level of reliability with caregivers (ICC=0.51), followed by the physician (0.42), and the clinical research coordinator (0.32). Stratifying by timepoint resulted in excellent reliability for baseline, PICU discharge, and follow-up data (ICC = 0.87, 0.85, 0.98, respectively). Conclusion: Large within-patient variability created by temporal effects made analyzing all data without regard to timing inappropriate and resulted in lower reliability. Prior experience played a factor in scoring ability which could be overcome with training. When timepoints were examined individually, FSS was moderately reliable for caregivers to complete. More research needs to be done by consulting with caregivers to determine if their understanding of the measure aligns with professionals. The public health and wellbeing of critically ill children can be improved by including caregivers in recovery efforts.