Inter-observer agreement of a comprehensive health status classification system for pre-school children among patients with Wilms' tumor or advanced neuroblastoma.

We assessed inter-observer agreement on a new comprehensive health status classification system for preschool children (CHSCS-PS). Prospective assessments of children aged 2-4.9 years at the time of diagnosis of neuroblastoma (stages 3-4, excluding 4S) or Wilms' tumor (stages II-V) were collected independently from a parent and nurse by self-report during therapy. Responses were used to determine functional status on 10 health domains, as well as an overall disability score. Inter-observer agreement was evaluated by a kappa statistic for agreement about levels within individual domains, and by an intraclass correlation coefficient (ICC) for agreement of overall disability scores. Twenty-four parent/nurse pairs of assessments were collected. Agreement was almost perfect for mobility and self-care, substantial for emotion and pain, and slight for speech. There was high percent agreement for vision, hearing, dexterity, learning and remembering, and thinking and problem solving, but insufficient variability in responses to calculate a kappa statistic. The ICC for overall disability scores between observers was 0.86, indicating strong agreement. Given the need for, and paucity of, instruments for the measurement of health-related quality of life in very young children, these results strongly support further evaluation of the CHSCS-PS.