Initial validation of the global assessment of severity of illness

Scales currently validated to assess severity of chronic physical conditions in children are not well suited for limited-resource settings as they lack ease of use and interpretation. This study assessed the validity of the Global Assessment of Severity of Illness (GASI), a single-item scale designed for quick and simple assessment of illness severity in children with various chronic physical conditions. Study objectives were to examine validity, reliability, and responsiveness of the GASI. Clinicians assessed the severity of asthma, food allergy, epilepsy, diabetes, and juvenile arthritis in 55 children, and parents reported on children’s health-related quality of life. Area under the curve (AUC) computed by logistic regression and Kendall’s Tau-c (τc) assessed the strength of association between the GASI and other study measures. The kappa coefficient (κ), weighted kappa (κw), and McNemar’s test assessed stability in GASI ratings over time. The standardized response mean and Guyatt’s responsiveness index examined internal and external responsiveness of the GASI, respectively. The GASI correlated strongly with established severity scales (AUC = 0.83–0.96; τc = 0.57–0.78) and did not correlate with health-related quality of life (τc