Intervention Review

Protein substitute for children and adults with phenylketonuria

  1. Sarah HL Yi2,
  2. Rani H Singh1,*

Editorial Group: Cochrane Cystic Fibrosis and Genetic Disorders Group

Published Online: 8 OCT 2008

Assessed as up-to-date: 10 MAR 2011

DOI: 10.1002/14651858.CD004731.pub3


How to Cite

Yi SHL, Singh RH. Protein substitute for children and adults with phenylketonuria. Cochrane Database of Systematic Reviews 2008, Issue 4. Art. No.: CD004731. DOI: 10.1002/14651858.CD004731.pub3.

Author Information

  1. 1

    Emory University School of Medicine, Department of Human Genetics, Decatur, Georgia, USA

  2. 2

    Decatur, Georgia, USA

*Rani H Singh, Department of Human Genetics, Emory University School of Medicine, 2165 North Decatur Road, Decatur, Georgia, 30033, USA. rsingh@genetics.emory.edu.

Publication History

  1. Publication Status: New search for studies and content updated (no change to conclusions)
  2. Published Online: 8 OCT 2008

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Abstract

  1. Top of page
  2. Abstract
  3. Plain language summary
  4. 摘要

Background

Phenylketonuria is an inherited metabolic disorder characterised by an absence or deficiency of the enzyme phenylalanine hydroxylase. The aim of treatment is to lower blood phenylalanine concentrations to the recommended therapeutic range to prevent developmental delay and support normal growth. Current treatment consists of a low-phenylalanine diet in combination with a protein substitute which is free from or low in phenylalanine. Guidance regarding the use, dosage, and distribution of dosage of the protein substitute over a 24-hour period is unclear, and there is variation in recommendations among treatment centres.

Objectives

To assess the benefits and adverse effects of protein substitute, its dosage, and distribution of dose in children and adults with phenylketonuria who are adhering to a low-phenylalanine diet.

Search methods

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials Register which consists of references identified from comprehensive electronic database searches and hand searches of relevant journals and abstract books of conference proceedings. We also contacted manufacturers of the phenylalanine-free and low-phenylalanine protein substitutes for any data from published and unpublished randomised controlled trials.

Date of the most recent search of the Group's Trials Register: 22 July 2010.

Selection criteria

All randomised or quasi-randomised controlled trials comparing: any dose of protein substitute with no protein substitute; an alternative dosage; or the same dose, but given as frequent small doses throughout the day compared with the same total daily dose given as larger boluses less frequently.

Data collection and analysis

Both authors independently extracted data and assessed trial quality.

Main results

Three trials (69 participants) are included in this review. One trial investigated the use of protein substitute in 16 participants, while a further two trials investigated the dosage of protein substitute in a total of 53 participants. Due to issues with data presentation in each trial, described in full in the review, formal statistical analyses of the data were impossible. Investigators are being contacted for further information.

Authors' conclusions

No conclusions could be drawn about the short- or long-term use of protein substitute in phenylketonuria due to the lack of adequate or analysable trial data. Additional data and randomised controlled trials are needed to investigate the use of protein substitute in phenylketonuria. Until further evidence is available, current practice in the use of protein substitute should continue to be monitored with care.

 

Plain language summary

  1. Top of page
  2. Abstract
  3. Plain language summary
  4. 摘要

The impact of protein substitute on the nutrition status, growth, and neuropsychological performance of children and adults with phenylketonuria

People with phenylketonuria (PKU) who follow a low-phenylalanine diet are required to take protein substitute to ensure adequate consumption of protein, energy, and other nutrients. The need for protein substitute has been established through clinical experience and observational data. Randomised, controlled trials are needed to confirm this need as well as its proper dosage and frequency of use. We performed a systematic review of randomised control trials investigating the impact of the use, dosage, and distribution of protein substitute on physical and neuropsychological outcomes in the treatment of PKU. Trials of children and adults diagnosed with PKU in the newborn period who were treated early and continuously were included. We planned to pool the results of the trials to estimate treatment effect. Three trials met the inclusion criteria for the review. One trial evaluated the impact of protein substitute versus no protein substitute on neuropsychological status, plasma amino acid concentrations, and nutrient intake. The remaining two trials investigated the impact of differing dosages of protein substitute on plasma amino acid concentrations and nutrient intake. No trials investigating daily protein substitute distribution were eligible for inclusion in the review. Results are presented in text form only since adequate information for data pooling was not provided. The investigators are being contacted for further information. Currently data are insufficient to reach any conclusions regarding the use, dosage, and distribution of protein substitute in the treatment of PKU. Further randomized or controlled clinical trials are needed to provide evidence for the effectiveness, dosage, and distribution of protein substitute in the treatment of PKU.

 

摘要

  1. Top of page
  2. Abstract
  3. Plain language summary
  4. 摘要

背景

苯酮尿症病童及成人患者的蛋白質替代品

典型苯酮尿症是因代謝苯丙胺酸的PAH(Phenylalanine hydroxylase)酵素不足或缺乏所導致的遺傳疾病。治療目標為降低血中苯丙胺酸的數值,使之維持在理想數值內,避免發展遲緩並維持正常生長發育。目前治療方式為採行低苯丙胺酸飲食,並配合使用蛋白質替代品(為不含或含低苯丙胺酸的胺基酸混合物)。但蛋白質替代品的使用準則、劑量及24小時期間的劑型分佈尚不明確,再者各醫療中心的建議使用量也有不同的差異。

目標

研究對象為採行低苯丙胺酸飲食的苯酮尿症病童及成人患者,以評估他們在使用蛋白質替代品上的成效、副作用,及其使用劑量的份量及分佈。

搜尋策略

我們搜尋Cochrane囊狀纖維化及遺傳疾病群組試驗登記資料庫;包括了各廣泛的電子資料庫搜索系統,並實際查詢相關的期刊文獻以及會議議程的摘要手冊。我們也連絡了製造不含苯丙胺酸及低苯丙胺酸蛋白質替代品的廠商,藉以選取已出版或未出版的隨機對照試驗。最新進入先天代謝異常疾病試驗登記資料庫的搜索日期為2008年4月。

選擇標準

選取所有以隨機對照試驗(randomised controlled trials)或近隨機對照試驗(quasirandomised controlled trials)所做的研究:包括使用任何劑量的蛋白質替代品及沒有使用蛋白質替代品;固定及可自由選擇的使用劑量;或在相同劑量下,但是以一天多次小分劑量的方式及同等的每日劑量採較少次數較大分劑量之間的比較。

資料收集與分析

兩位作者都各自獨立的選取資料,及評估其試驗的品質。

主要結論

本篇評論包括三篇研究(共69名受試者),其中一篇包括16位蛋白質替代品的受試者,此外兩篇則針對53位蛋白質替代品使用者的使用劑量進行研究。由於研究數據陳述在各篇研究中,已於評論中詳細說明,因此無法進行數據上的統計分析。 研究者正著手搜尋更多的資訊。

作者結論

由於缺乏合適的研究資料,而無法對短期或長期使用苯酮尿症蛋白質替代品做出結論來。為研究苯酮尿症患者對蛋白質替代品的使用,仍需進行隨機對照的試驗。在未來研究結果可以得到佐證之前,目前在蛋白質替代品的實際使用上,仍應持續小心的予以觀察及監測。

翻譯人

本摘要由臺灣大學附設醫院蕭雅慧翻譯。

此翻譯計畫由臺灣國家衛生研究院(National Health Research Institutes, Taiwan)統籌。

總結

接受飲食控制的苯酮尿症患者,需補充蛋白質替代品,方以確保能獲得足夠身體所需的蛋白質、能量及其他營養物質。雖然已經由臨床經驗和觀察,了解蛋白質替代品在使用上的需要,但仍需藉隨機對照的實驗研究,以確定其適當的使用劑量及使用頻率。因此我們針對隨機對照的實驗研究,進行系統性的分析調查,以了解蛋白質替代品在治療苯酮尿症患者的使用情形、劑量、分佈情形,和對生理及神經心理等各方面的影響。 研究對象為於新生兒期接受診斷後,即開始並持續接受飲食治療的苯酮尿症兒童及成人,並將彙整相關研究結果後,評估其治療成效。 結果有三篇文獻符合納入標準;其中一篇為比較使用及未使用蛋白質替代品,對患者神經心理狀況、血中苯丙胺酸數值,及營養攝入情形等各方面的影響。其餘兩篇則在於探討不同的使用劑量,對血中胺基酸濃度和營養攝入的影響。在每日使用劑量上,目前沒有符合納入標準的研究。若是未有合適的資料結果,則將僅以文字進行描述。 目前調查者正著手於取得更多進一步的相關資訊。對於苯酮尿症患者在使用蛋白質替代品的劑量和使用情形上,目前所得資料還不足以達成結論,仍需將來更多的相關臨床試驗,以提供更多治療上的建議。