Table 3.

Conceptualising the impact of disease [85]

Disease context: Phenylketonuria (PKU) is a genetic disorder characterised by a deficiency of the hepatic enzyme, phenylalanine hydroxylase; left untreated, it can lead to intellectual impairment, deficit in cognitive functions, seizures, behavioural problems and psychiatric symptoms.

Study & methods: To develop a new PRO instrument based on a conceptual model of PKU through exploratory interviews with clinical experts, adults and adolescents with PKU, and parents with young children with PKU.

Result: The conceptual model of PKU impact included health status (cognitive function, symptoms, monitoring); psychological function; social function; and diet. Potential mediators of disease impact included adherence, coping, social support, and other sociodemographic characteristics. For illustration purposes, the conceptual model is available in Additional file 1.