The PKU & ME study: A qualitative exploration, through co-creative sessions, of attitudes and experience of the disease among adults with phenylketonuria in Italy

Adult PKU Clinics in the UK-Users' Experiences and Perspectives

Adults with PKU require life-long management, and ideally, their care should be in a specialised adult metabolic clinic. Their outcomes and co-morbidities have received much attention, but data are lacking on their experience, satisfaction and expectations about the care they receive. This survey reports the experiences and care adults with PKU receive from specialist metabolic clinics in the UK. The online survey developed by the UK NSPKU (National Society for Phenylketonuria), was placed on the NSPKU website from February 2021 to December 2022, and was completed by adults with PKU (≥18 years) or their carers/family members. Sixty-five adult PKU patients and 9 caregivers of adult patients completed the questionnaire (63% female in total). Only 32% of respondents were following a Phe-restricted diet with protein substitute intake as prescribed; the rest were partially adherent or not on dietary restrictions. Nineteen per cent (n = 14/74) had not been reviewed in clinic for two years. Half of the respondents (50%) described their experience in adult clinics as "good". Half of the patients were unable to contact their dietitians with questions or concerns, and only 24% considered that they received adequate support. Clinic reviews usually included anthropometric (82%) and dietary assessments (64%), discussion on management of PKU in daily life (78%) and a blood test (71%). Eighty-eight per cent reported they had at least one neurocognitive, mental health or behavioural co-morbidity but less than half of the patients reported an assessment on their neurocognitive functioning or mental health issues. Adult male patients appeared to have less detailed clinic review than females. Less than half (44%) of the respondents reported that they performed a blood spot for blood Phe at least monthly, but only 32% considered they had been informed about the risk of high Phe levels in adulthood. Although time, cost and stress related to travelling were barriers to a face-to-face review, more than 40% of patients had concerns about remote appointments. The frequency and extent of monitoring of adults with PKU, attending specialist adult services, were less than those specified by the PKU European guidelines. The care of women of reproductive age is prioritised over men. Adult metabolic health services require further attention, development and resources to provide a high standard and equitable service to patients with PKU.

Expert Consensus on the Long-Term Effectiveness of Medical Nutrition Therapy and Its Impact on the Outcomes of Adults with Phenylketonuria

Many adults with phenylketonuria (PKU) rely on medical nutrition therapy (MNT; low phenylalanine (Phe) diet with protein substitutes/medical foods) to maintain blood Phe concentrations within recommended ranges and prevent PKU-associated comorbidities. Despite disease detection through newborn screening and introduction of MNT as early as birth, adherence to MNT often deteriorates from childhood onwards, complicating the assessment of its effectiveness in the long term. Via a modified Delphi process, consensus (≥70% agreement) was sought on 19 statements among an international, multidisciplinary 13-member expert panel. After three iterative voting rounds, the panel achieved consensus on 17 statements related to the limitations of the long-term effectiveness of MNT (7), the burden of long-term reliance on MNT (4), and its potential long-term detrimental health effects (6). According to the expert panel, the effectiveness of MNT is limited in the long term, is associated with a high treatment burden, and demonstrates that adults with PKU are often unable to achieve metabolic control through dietary management alone, creating an unmet need in the adult PKU population.

Transitioning of protein substitutes in patients with phenylketonuria: evaluation of current practice

Background

In children with phenylketonuria (PKU), transitioning protein substitutes at the appropriate developmental age is essential to help with their long-term acceptance and ease of administration. We assessed the parental experiences in transitioning from a second stage to third stage liquid or powdered protein substitute in patients with PKU.

Results

Sixteen interviews (23 open-ended questions) were carried out with parents/caregivers of children with PKU (8 females, 50%) with a median age of 8 years (range 5–11 years), continuously treated with diet, and on a third stage protein substitute. Parents/caregivers identified common facilitators and barriers during the third stage protein substitute transition process. The main facilitators were: child and parent motivation, parent knowledge of the transition process, a role model with PKU, low volume and easy preparation of the third stage protein substitute (liquid/powder), anticipation of increasing child independence, lower parent workload, attractive packaging, better taste and smell, school and teacher support, dietetic plans and guidance, PKU social events, child educational materials and written resources. The main barriers were child aversion to new protein substitutes, poor child behaviour, child aged > 5 years, parental fear of change, the necessity for  parental time and persistence, loss of parental control, high product volume, different taste, smell, and texture of new protein substitutes, and peer bullying.

Conclusion

A stepwise, supportive approach is necessary when transitioning from second to third stage protein substitutes in PKU. Future studies are needed to develop guidance to assist parents/caregivers, health professionals, and teachers during the transition process.

Moving through adulthood: The lived experience of Irish adults with PKU

Background

This paper represents a portion of the findings from one of the first research studies eliciting the lived experience of adults with an early diagnosis of Phenylketonuria (PKU) living in Ireland. Ireland has one of the highest prevalence rates of PKU in Europe, however, little is known about the experience of Irish adults with PKU. Furthermore, Ireland is one of the first countries in the world to introduce neonatal screening followed by the introduction of long-term dietary therapy over 50 years ago. This study presents the first comprehensive assessment of the lived experience of Irish adults with PKU on long term dietary therapy.

Methods

Narrative data was collected from eleven self-selected participants, using semi-structured interviews. The interviews were divided into five sections focused on eliciting a holistic understanding of the lived experience of adults with PKU living in Ireland. Thematic analysis was guided by Colaizzi's Framework (1978) in conjunction with NVivo qualitative data analysis software.

Findings

Findings from the original research encompassed a broad understanding of the lived experience of adults with PKU living in Ireland, including factors influencing dietary therapy and managing PHE blood levels. The themes being discussed within this article are those which appear to be least represented within current literature: living with PKU, including reproductive health, the importance of self-management and establishing routine, support networks in adulthood and concerns regarding aging with PKU.

Conclusion

It was evident from the findings that a diagnosis of PKU can influence how adults with PKU may experience aging and their own mortality. These findings offer new insight into the vulnerability attached to the experience of aging with PKU and may be beneficial to advocacy groups and for future development of policy and practice.

Exploring the Barriers and Motivators to Dietary Adherence among Caregivers of Children with Disorders of Amino Acid Metabolism (AAMDs): A Qualitative Study

Dietary intervention is generally accepted as the mainstay of treatment for patients with disorders of amino acid metabolism (AAMDs). However, dietary adherence to a low-protein diet is always reported as a common challenge among these patients. This study explored the perception of barriers and motivators to dietary adherence among caregivers of AAMD patients in Malaysia. Twenty caregivers of children with AAMDs receiving ongoing treatment at the genetic clinic participated in an online focus group discussion from November to December 2021. Findings showed a total of five interrelated main themes identified from focus group discussion (FGD) exploring parents’ experiences related to the management of their child’s daily diet. The barriers to dietary adherence were burden of dietary treatment, diet and dietary behavior, parenting challenges, limited knowledge related to dietary treatment, and challenges in healthcare system delivery. Key factors facilitating good dietary adherence include good knowledge of dietary treatment, parental coping strategies, social coping, and dietary behavior. In conclusion, despite the existence of several barriers to the implementation of dietary treatment, caregivers managed to use a wide range of coping strategies to overcome some, if not all, of the challenges. The important next step is to develop, in conjunction with multidisciplinary healthcare professionals, feasible implementation strategies that could address these barriers and at the same time improve the quality of life of caregivers.

The management of transitional care of patients affected by phenylketonuria in Italy: Review and expert opinion

Phenylketonuria (PKU) is a metabolic inherited disorder in which transition from infancy to adult care is particularly difficult and not sufficiently regulated. According to the scientific literature, only few medical centers offer healthcare assistance for adult patients with PKU that are therefore still treated in pediatric settings. This generates psychological, emotional, and organizational discomfort among patients, leading them to discontinue the follow-up. European guidelines and national consensus documents underline this unmet need and the lack of practical recommendations for a structured transitional pathway in PKU. The aim of this review and expert opinion is to propose good practices for managing the transition period of PKU patients, based on the literature and the experience of a panel of Italian experts in PKU. The consensus of the experts was obtained through the administration of three rounds of surveys and one structured interview. The result is the first proposal of a pathway for an efficient transition of PKU patients. Key steps of the proposed pathway are the "a priori" planning involving the pediatric and adult teams, the acceptance of the patient and his/her family to the process, the preliminary definition of appropriate spaces in the structure, the organization of meetings with the joint team, and the appointment of a transition coordinator. For the first time, the involvement of decision makers and patient associations is proposed.

Italian national consensus statement on management and pharmacological treatment of phenylketonuria

BACKGROUND

Phenylketonuria (PKU) is a rare inherited metabolic disorder caused by defects in the phenylalanine-hydroxylase gene (PAH), the enzyme catalyzing the conversion of phenylalanine to tyrosine. PAH impairment causes phenylalanine accumulation in the blood and brain, with a broad spectrum of pathophysiological and neurological consequences for patients. Prevalence of disease varies, with peaks in some regions and countries, including Italy. A recent expert survey described the real-life of clinical practice for PKU in Italy, revealing inhomogeneities in disease management, particularly concerning approach to pharmacotherapy with sapropterin hydrochloride, analogous of the natural PAH co-factor, allowing disease control in a subset of patients. Therefore, the purpose of this paper is to continue the work initiated with the expert survey paper, to provide national guidances aiming to harmonize and optimize patient care at a national level.

PARTICIPANTS

The Consensus Group, convened by 10 Steering Committee members, consisted of a multidisciplinary crowd of 46 experts in the management of PKU in Italy.

CONSENSUS PROCESS

The Steering Committee met in a series of virtual meeting in order to discuss on clinical focuses to be developed and analyzed in guidance statements, on the basis of expert practice based evidence, large systematic literature review previously performed in the expert survey paper, and evidence based consensus published. Statements were re-discussed and refined during consensus conferences in the widest audience of experts, and finally submitted to the whole consensus group for a modified-Delphi voting.

RESULTS

Seventy three statements, divided in two main clinical areas, PKU management and Pharmacotherapy, achieved large consensus in a multidisciplinary group of expert in different aspects of disease. Importantly, these statements involve guidances for the use of sapropterin dihydrochloride, still not sufficiently implemented in Italy, and a set of good practice to approach the use of novel enzyme replacement treatment pegvaliase.

CONCLUSIONS

This evidence-based consensus provides a minimum set of guidances for disease management to be implemented in all PKU centers. Moreover, these guidances represent the first statement for sapropterin dihydrochloride use, implementation and standardization in Italy, and a guide for approaching pegvaliase treatment at a national level on a consistent basis.

PKU and COVID19: How the pandemic changed metabolic control

BACKGROUND

COVID19 pandemic urged the need to take severe measures for reducing the epidemic spread. Lockdowns were imposed throughout countries and even Inborn errors of metabolism (IEMs) affected patients had to face it and adapt, with management strategies changes coming along. Phenylketonuria (PKU) is an inborn error of phenylalanine (Phe) metabolism causing, when not treated, blood Phe increases and consequent central nervous system (CNS) damage. Dietary intervention is the main recognized treatment and must be maintained long-life, however adherence is often suboptimal in adulthood. Aim of this study was to evaluate whether and how the pandemic had impacted PKUs metabolic control and what factors may have played a role as potential modifiers.

METHODS

Patients ≥4 yo and in follow-up at our Metabolic Clinic were enrolled in this study, divided into subgroups according to age (GROUP A < 12 yo; GROUP B ≥ 12 yo). Videoconsults were conducted on a minimum monthly basis and collected DBS were studied and compared to previous year same time-period in order to evaluate possible changes.

RESULTS

39% of patients (n = 121) increased the number of performed DBS. "Non-compliant" patients were reduced (11-3%) with a - 14% of patients with mean Phe levels >600 umol/l and a - 8% of patients with 100% DBS above same level. GROUP A maintained substantially unchanged metabolic control among two analyzed time-periods. On the contrary, GROUP B demonstrated significant reductions in mean blood Phe concentrations (p < 0.0001) during the pandemic (mean 454 umol/l, SD ± 252, vs. 556.4 umol/l, SD ± 301).

DISCUSSION

COVID19 pandemic strongly impacted people's life with lifestyle habits changing consistently. PKU patients had to adapt their dietary restrictions to the new environment they were exposed to and, if younger patients could have been less exposed (meals strictly according to diet plan independently from setting), adolescent and adults strongly reflected the obligation to stay home by showing better metabolic control. Multiple factors could have played a role in that and the availability of teleconsultancy may have contributed allowing easier connections, but our data demonstrate how the pandemic and the environment can strongly impact PKUs adherence to treatment and how removing distance barriers can ameliorate and optimize metabolic compliance.

The management of phenylketonuria in adult patients in Italy: a survey of six specialist metabolic centers

INTRODUCTION

Phenylketonuria (PKU) is a rare autosomal recessive disorder caused by a deficiency of phenylalanine hydroxylase (PAH). Its prevalence is estimated to be 1:10,000 in Europe. PKU is the commonest congenital inborn error of metabolism. The aim of our study was to investigate the characteristics of clinical practice in relation to PKU in Italy, in order to raise awareness about the current management and therapeutic approaches adopted.

METHODS

Six Italian experts conducted a systematic literature review as well as an internal survey to investigate the relevant clinical aspects. Collectively, the expert panel managed a total of 678 PKU patients treated in the early stages of the condition over a 16-year period across six centers.

RESULTS

The management of PKU varied markedly between centers, with differences in the composition of the multidisciplinary team, dietary treatments, compliance and adherence to management, tetrahydrobiopterin use, and patient follow-up. Patients were mostly managed by a pediatric reference center from the initial PKU diagnosis during newborn screening until adulthood, without transition to a specialized adult clinician. Fogginess, concentration reduction, low attention, anxiety, irritability, memory deficit, headache, and unstable mood were common features in patients with uncontrolled blood phenylalanine levels (generally above 600 µmol/L).

CONCLUSION

A homogeneous and shared approach to the management of PKU patients is important. Our survey demonstrates the current management of PKU in Italy, with the aim of promoting the implementation of therapeutic strategies and follow-up, increased patient compliance and adherence, and the achievement of the phenylalanine level targets recommended by European Union guidelines. Emerging therapies are likely to become a standard treatment for patients unable to comply with diet therapy and maintain their phenylalanine levels below the threshold values.

Supplemental data for this article is available online at https://doi.org/10.1080/03007995.2020.1847717.

Health Related Quality of Life assessment among early-treated Hungarian adult PKU patients using the PKU-QOL adult questionnaire

Background: The implementation of neonatal screening and the early initiation of lifelong therapy have helped to prevent severe complications and enabled much more favorable outcomes for early-treated phenylketonuria (ETPKU) patients. However, PKU patients tend to develop subtle cognitive and psychosocial abnormalities and the strict dietary therapy can present financial and social burden. Thus, PKU is expected to affect the quality of life (QoL) of these patients. There is insufficient evidence regarding the relationship between metabolic control and Health-Related QoL (HRQoL). We aimed to assess the effect of short- and long-term therapy on QoL among Hungarian adult PKU patients using the standardized PKU-specific PKU-QoL questionnaire.

Methods: We conducted a single-centre, cross-sectional, observational study in Hungary. We included adult PKU patients treated with diet and amino acid supplements only. Patients reported HRQoL using the standardized adult PKU-QoL questionnaire and mean blood Phe concentrations were assessed for three different time periods: the previous 10 years, the previous year and concentration at the time of completing the questionnaire. The correlation between patients’ QoL scores and their Phe levels was assessed. The classical PKU group was further divided into “good” and “suboptimal” adherence groups based on individual mean Phe levels in the examined time period. We evaluated differences in QoL among the two subgroups of classical PKU patients. QoL scores between classical and non-classical patients were also compared.

Results: Data from 88 adult patients were analysed (66 had classical PKU). No median PKU-QoL score reached major or severe impact/frequent symptoms in any domain. The highest scores (meaning larger burden) were mostly related to emotional impact of PKU and disease management. When performing correlation analysis between Phe levels and QoL scores by all patients we found weak to fair positive correlation in several domains either short or long term. Patients with classical PKU reported greater financial impact of PKU than patients with less severe PKU. Classical PKU patients with good therapy adherence tended to report better HRQoL scores than patients with suboptimal adherence.

Conclusion: We conclude that patients showed good HRQoL using the PKU-specific questionnaire. Our study demonstrates that suboptimal metabolic control is negatively associated with patients' HRQoL.