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Table 8 Reliability coefficients of the Parent PKU-QOL questionnaire at baseline in the parent evaluable population (n = 253)

From: Development and psychometric validation of measures to assess the impact of phenylketonuria and its dietary treatment on patients’ and parents’ quality of life: the phenylketonuria – quality of life (PKU-QOL) questionnaires

Parent PKU-QOL scores

Cronbach’s α

ICC

Child health status

-

0.59

Headaches

-

0.47

Stomach aches

-

0.41

Tiredness

-

0.58

Irritability

-

0.65

Aggressiveness

-

0.69

Moodiness

-

0.61

Sadness

-

0.48

Anxiety

-

0.60

Lack of concentration

-

0.63

Slow thinking

-

0.60

Emotional impact of PKU

0.63

0.78

Practical impact of PKU

0.74

0.76

Social impact of PKU

0.72

0.80

Overall impact of PKU

0.84

0.84

Anxiety – blood test

0.73

0.85

Impact of anxiety – blood test

0.76

0.78

Anxiety – blood Phe levels

-

0.79

Financial impact of PKU

-

0.78

Information on PKU

-

0.63

Adherence to Phe-free protein supplements

-

0.42

Management of Phe-free protein supplements

-

0.61

Practical impact of Phe-free protein supplements

0.77

0.66

Guilt if poor adherence to Phe-free protein supplements

-

0.59

Relationships within family because of Phe-free protein supplements

-

0.59

Adherence to dietary protein restriction

-

0.29

Management of dietary protein restriction

0.85

0.78

Practical impact of dietary protein restriction

0.82

0.79

Food enjoyment

-

0.35

Guilt if dietary protein restriction not followed

-

0.70

  1. ICC: Intraclass Correlation Coefficient; Phe: phenylalanine; PKU: phenylketonuria; QOL: quality of life. Reliability coefficients ≥0.70 are set in bold type.