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Comprehensive analysis of current PKU management practices and associated patient and parent-reported outcomes in Canada Yuskiv, Nataliya


Phenylketonuria (PKU) is a genetic metabolic disorder requiring life-long treatment to prevent severe neurocognitive disability. Despite early treatment, suboptimal neurobehavioral outcomes are common in individuals with PKU. The Canadian Inherited Metabolic Diseases Research Network (CIMDRN) presented an opportunity to investigate current approaches to care and associated outcomes in children with PKU and their parents. Four studies were conducted herein. The surveys of Canadian metabolic dietitians and physicians, described in Chapter 2, helped to understand current PKU management practices from the perspectives of healthcare providers. Data reflecting practices in metabolic treatment centres and associated outcomes were derived from the CIMDRN clinical longitudinal PKU database (Chapter 3). Finally, parent-reported child’s health and parental quality of life were analyzed in connection to the quality of metabolic control (Chapter 4). Providers’ surveys identified overall compliance with current PKU guidelines. Variation was found in case ascertainment, diagnostic workup (neonatal BH4 loading test), monitoring and follow up tests (neuropsychological assessments), treatment practices (sapropterin and large neutral amino acids, LNAA) and organization of care in metabolic centres. The mean phenylalanine (Phe) levels were within the recommended range of 120-360 µmol/L but increased (to 331±151 µmol/L) beyond 7 years of age for children with classic PKU. Among children with classic PKU, 32% were considered in good metabolic control by the 4th week of life. This increased to 55% by age 4-5 and declined to 28% at 8-9 years. Tiredness, lack of concentration, irritability and moodiness were reported as moderate symptoms in children. Parents reported considerable guilt due to non-adherence to the diet/supplements, their child’s anxiety, and practical impact of dietary protein restriction. Overall, healthcare providers follow the published guidelines in providing care for their patients. However, this work has identified variation in many areas of PKU nutritional and clinical management practices in Canadian metabolic centres, including diagnostic and follow up nutritional and clinical management practices. This variation has the potential to impact patients’ long-term health outcomes. The most variation was in areas of practice that were not strongly supported by empirical evidence. This knowledge will serve to further optimize health and quality of life outcomes in Canadian children with PKU.

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