Development of Health-related Quality of Life Instrument for Patients With Cystinosis

Semi-structured interviews with young patients with cystinosis and their parents to identify relevant aspects of disease-specific HrQoL

Semi-structured interviews are conducted to create a pilot test version of the preliminary disease-specific HrQoL tool (QUALIFY). The results of the qualitative analysis will be used to derive an initial item list and response categories of the preliminary questionnaire.

Pilot-test version including a cognitive debriefing to assess the preliminary disease-specific HrQoL tool (QUALIFY) for young people with cystinosis

A pilot-testing of the preliminary version of the QUALIFY questionnaire, including a cognitive debriefing, are performed, so that young patients and parents report on the comprehensibility, completeness, and cultural applicability of the questionnaire from their perspective.

Field-test and of the final version of the disease-specific HrQoL tool (QUALIFY) for young people with cystinosis

A field- and re-test for psychometric assessment of the final version of the QUALIFY questionnaire is performed.

Health related quality of life measured by the chronic-generic DISABKIDS Questionnaire

The 12-item short form of the DISABKIDS Questionnaire is used to assess the HrQoL of children and adolescents with chronic medical conditions from their own as well as their parents' perspectives. The questionnaire consists of three domains: Mental (4 items), social (4 items) and physical (4 items). One composite score can be calculated. Higher scores indicate better HrQoL.

Health related quality of life measured by the generic PedsQL™ Generic Core Scales

For the age group 2-4 years, the generic HrQoL of toddlers is assessed via parent report. It consists of 21 items and describes 4 dimensions (Physical Functioning (8 items) Emotional Functioning (5 items) Social Functioning, (5 items), School Functioning (3 items)). The following Scores can be computed: Total Scale Score (21 items); Physical Health Summary Score (8 items); Psychosocial Health Summary Score (15 items). The 23-item PedsQL™ Generic Core Scales measure generic HrQoL in children, adolescents, and young adults in self-report as well as proxy report. There are four multidimensional scales (Physical Functioning (8 items) Emotional Functioning (5 items) Social Functioning, (5 items), School Functioning (5 items)) and three summary scores: Total Scale Score (23 items); Physical Health Summary Score (8 items); Psychosocial Health Summary Score (15 items). In both versions, scores are transformed to a 0 to 100 scale and higher scores indicate better HrQoL.

Health related quality of life measured by the generic PedsQL™ Infant Scales

The PedsQL™ Infant Scales measure generic HrQoL in infants aged 1-12 and 13-24 months in proxy report. The version for infants ages 1-12 months consists of 36 items. There are five multidimensional scales (Physical Functioning (6 items), Physical Symptoms (10 items), Emotional Functioning (12 items) Social Functioning, (4 items), Cognitive Functioning (4 items)). The version for infants ages 13-24 months consists of 45 items. There are five multidimensional scales (Physical Functioning (9 items), Physical Symptoms (10 items), Emotional Functioning (12 items) Social Functioning, (5 items), Cognitive Functioning (9 items)). In both versions, scores are transformed to a 0 to 100 scale and higher scores indicate better HrQoL. Three summary scores can be calculated: Total Scale Score (all items); Physical Health Summary Score (using items of Physical Functioning and Physical Symptoms); Psychosocial Health Summary Score (Emotional, Social, and Cognitive Functioning items).

Impact of pediatric chronic health condition on parents and the family by the PedsQL™ Family Impact Modules

The 36-item PedsQL™ Family Impact Module describes 8 dimensions: parent self-reported physical functioning (6 items), emotional functioning (5 items), social functioning (4 items), and cognitive functioning (5 items), communication (3 items), worry (5 items), as well as parent-reported family daily activities (3 items) and family relationships (5 items). Scores are transformed to a 0 to 100 scale. Higher scores indicate better functioning. Three summary scores can be calculated: Total Scale Score (36 items); Parent HrQoL Summary Score (20 items); Family Functioning Score (8 items).