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We thank Professor Wright for her comments, and we welcome the opportunity to provide some clarification and further analysis.
We reported Z-scores rather than percentiles, although some comments on approximate percentiles can be made. Assuming that Z scores of -1.96 and -3 represent approximately the 2.5th and 0.2nd centiles respectively, 36/101 children were below the 2.5th centile, and 17/101 were below the 0.2nd centile for weight. Additionally, our mixed effects model (accounting for multiple measurements) modelling the group trend over time estimated the mean weight Z score at 11 years to be -1.63 (approximately 5th centile).
Despite the overall short stature of the group, 24/101 children had a BMI Z score of less than -1.96. So, by this approach, their weight was low even after taking into account stature. We agree that we cannot infer causality from this observational study, but we believe a proportion of the stunted growth is explained by low weight. We are exploring other measures of malnutrition, such as skin-fold thickness.
Whilst our patient numbers are small, they do give some weight to the argument that PEG feeding halts the progression of malnutrition. We investigated the rate of decline of weight after PEG insertion. In a mixed effects model with a random intercept for individual patients, the rate of wei...
Whilst our patient numbers are small, they do give some weight to the argument that PEG feeding halts the progression of malnutrition. We investigated the rate of decline of weight after PEG insertion. In a mixed effects model with a random intercept for individual patients, the rate of weight Z score decline was 0.01 units per year, in contrast with 0.1 per year in the un-operated population, although low numbers prevent a meaningful statistical comparison. Given the ultra-rare nature of the disease, a randomised trial is effectively impossible and probably anyway unethical.
The multifactorial aetiology of wasting is unique in A-T. The disease compromises varying components of chronic inflammation, poor feeding ability, and increased calorie consumption due to dystonic and athetoid movements. The prognosis in A-T is truly appalling, and therefore we aim for the best possible quality of life. As well as showing that PEG feeding halts the progression of malnutrition (albeit in small numbers of children as compared to controls) and making feeding safer in the presence of possible aspiration, one consistent theme (not reported in our paper but consistently reported by parents in our clinic and previously published by other groups(1)) is significant caregiver satisfaction and reduction in very lengthy meals times. This has a very significant impact in improving the quality of life of carers and patients.
It is well recognised in other chronic paediatric diseases, such as cystic fibrosis and chronic kidney disease that nutrition is a predictor of overall quality of life. Currently, we have very little to offer patients with A-T in terms of intervention to prevent the development of malignancy or neurological progression, but we believe by extrapolating from other similar patient groups, we can reduce the risk of death from pulmonary failure. Key to this is prevention of wasting.
All long term invasive medical technologies interfere with the human condition of childhood, and we wholeheartedly agree that a PEG is life-changing and should always be carefully considered on an individual basis. However, given the poor weight gain in many A-T children, we believe it is important to discuss whether a PEG would be useful early, and consider placement prior to the respiratory deterioration of the child.
Emma Stewart1, Andrew P Prayle2, Alison Tooke1, Sara Pasalodos3, Mohnish Suri3, Andy Bush4,5,6, Jayesh M Bhatt1
1 Nottingham Children's Hospital, National Paediatric Ataxia Telangiectasia Clinic, QMC, Nottingham, UK
2 University of Nottingham, School of Clinical Science, Queens Medical Centre, Child Health, Nottingham, UK
3 Nottingham Clinical Genetics Service, National Paediatric Ataxia Telangiectasia Clinic, Clinical Genetics Service, City Hospital Campus, Nottingham, UK
4 Imperial College, London, UK
5 National Heart and Lung Institute, London, UK
6 Royal Brompton & Harefield NHS Foundation Trust, London, UK
1. Lefton-Greif MA, Crawford TO, McGrath-Morrow S, Carson KA, Lederman HM. Safety and caregiver satisfaction with gastrostomy in patients with Ataxia Telangiectasia. Orphanet J Rare Dis. 2011;6:23.
I work in a clinic that specialises in helping children withdraw form or avoid tube feeding