Table 1.
Development and validation phases of the PKU-QOL questionnaire – disposition of subjects by phase and country
| France | Germany | Italy | Netherlands | Spain | Turkey | UK | Total | |
|---|---|---|---|---|---|---|---|---|
| Exploratory interviews | ||||||||
| Nutritionists | 4 | 3 | - | - | 4 | - | 6 | 17 |
| Pediatricians | 3 | 4 | - | - | 3 | - | 3 | 13 |
| Adolescents 13–17 years with PKU | 4 | 4 | - | - | 4 | - | 4 | 16 |
| Adults with PKU | 4 | 4 | - | - | 4 | - | 4 | 16 |
| Parents of children 4–12 years with PKU | 4 | 4 | - | - | 4 | - | 4 | 16 |
| Parents of adolescents 13–17 years with PKU | 0 | 0 | - | - | 3 | - | 0 | 3 |
| Comprehension testing | ||||||||
| Children 6–11 years with PKU | 3 | 3 | 3 | 3 | 3 | - | 3 | 18 |
| Adolescents 12–17 years with PKU | 4 | 4 | 4 | 4 | 4 | - | 4 | 24 |
| Adults with PKU | 5 | 4 | 4 | 3 | 4 | - | 4 | 24 |
| Parents of children with PKU | 5 | 5 | 5 | 5 | 5 | - | 6 | 31 |
| Linguistic validation | ||||||||
| Children 6–11 years with PKU | - | - | - | - | - | 3 | - | 3 |
| Adolescent 12–17 years with PKU | - | - | - | - | - | 3 | - | 3 |
| Adults with PKU | - | - | - | - | - | 3 | - | 3 |
| Parents of children with PKU | - | - | - | - | - | 3 | - | 3 |
| Psychometric Validation study | ||||||||
| Children 9–11 year with PKU | 13 | 19 | 15 | 7 | 20 | 14 | 4 | 92 |
| Adolescents 12–17 years with PKU | 10 | 20 | 26 | 10 | 20 | 20 | 4 | 110 |
| Adults with PKU | 18 | 21 | 22 | 7 | 21 | 8 | 7 | 104 |
| Parents of children ≤8 years with PKU | 10 | 8 | 8 | 6 | 8 | 6 | 6 | 52 |
| Parents of children 9–11 years with PKU | 13 | 19 | 15 | 7 | 20 | 4 | 14 | 92 |
| Parents of adolescents with PKU | 10 | 19 | 26 | 10 | 20 | 4 | 20 | 109 |