Effectiveness of Kinder Lebensqualität Fragebogen (KINDL) and Children's Somatic Symptom Inventory-24 (CSSI-24) for measuring postacute sequelae of COVID-19 in children: a diagnostic validation study.

Abstract

Background: The postacute sequelae of coronavirus disease 2019 (PASC), also known as pediatric long coronavirus disease (COVID), can significantly affect the quality of life (QoL) of affected children. Currently, there are no standardized screening tools to identify high-risk children. The Kinder Lebensqualität fragebogen (KINDL) is a psychometric method for measuring QoL in children.

Purpose: This study used the KINDL questionnaire and Children's Somatic Symptom Inventory-24 (CSSI-24) to evaluate symptom burden and establish a screening threshold for pediatric PASC.

Methods: We performed a cross-sectional study of children diagnosed with PASC defined as the presence of at least one persistent symptom lasting more than 4 weeks after a confirmed COVID-19 infection. Symptoms were assessed using a structured checklist developed by our team. The correlation between the KINDL and CSSI-24 scores was analyzed, and receiver operating characteristic (ROC) curve analysis was used to determine the optimal KINDL cutoff for identifying high-risk cases. QoL scores were also compared with those of historical cohorts to evaluate the impact of the PASC.

Results: We included 84 participants: 46 children (mean age, 8.74±1.77 years; 41.3% girls) and 38 adolescents (mean age, 14.50±1.56 years; 44.7% girls). KINDL and CSSI-24 scores showed a significant negative correlation (r=-0.44, P<0.001), suggesting that increased somatic symptoms were associated with a reduced QoL. The ROC analysis identified a KINDL cutoff score of 74.75 (area under the curve, 0.82) for detecting high-risk children. Compared to historical cohorts, children with PASC had QoL scores comparable to child-reported norms from 2010 but lower than parent-reported norms from the same year.

Conclusion: KINDL and CSSI-24 are practical tools for screening for pediatric PASC in outpatient settings. A KINDL cutoff of 74.75 may help clinicians identify children with PASC who require early intervention. Further studies in larger and more diverse populations are required to validate these findings.