Prevalence and Impact of Fatigue in Children with Primary Immunodeficiency Disorders: a Quantitative Single-Center Study.

Although fatigue is a common symptom in adult patients with primary immunodeficiencies (PID), data in pediatric patients are limited. The goal of this study is to estimate the prevalence and impact of fatigue in children with PID as reported by patients, parents, and health-care providers. A retrospective single-center observational study was performed. Prevalence of fatigue was measured by reviewing medical charts of 54 children in our department who are on immunoglobulin replacement therapy. Both prevalence and impact were also measured by the PedsQL-Multidimensional Fatigue Scale (MFS) in 27 patients and 32 of their parents. This is an age-appropriate questionnaire for self-report of fatigue symptoms in patients aged 5-18 years and for parent proxy reports for patients aged 2-18 years. General, cognitive, and sleep-rest fatigue was measured, and a total fatigue score was calculated. Means, standard deviation and Z scores were calculated using age-specific reference values. Intraclass correlation coefficients (ICC) were calculated for comparison of scores provided by parents vs children's self-reported scores. Both chart review data and PedsQL-MFS showed fatigue rates of 65%. Pediatric PID patients of all ages had significantly lower scores on all subscales and total score of the PedsQL-MFS compared to healthy children, indicating greater perceived symptoms of fatigue. General fatigue was the most affected subscale in PID patients, suggesting that fatigue in these patients is mainly physical. Seventy-four percent of PID patients had a Z score lower than - 1 on the general fatigue subscale indicating severe fatigue. Child-parent concordance varied between 0.24 and 0.93. Our results show the feasibility of the PedsQL-MFS survey to evaluate the prevalence and severity of fatigue in children with PID and underscore the importance of this issue in our patient care.