PEDIATRICS Vol. 118 No. 1 July 2006, pp. 432 (doi:10.1542/peds.2006-0641)
Behavioral and Nutritional Treatment to Improve Energy Intake and Growth in Toddlers and Preschool-Aged Children With Cystic Fibrosis
Marion Rowland, MB, PhDAnnemarie Broderick, MB, MSc
Billy Bourke, MD
University College Dublin School of Medicine and Medical Science,
Children's Research Centre,
Our Lady's Hospital for Sick Children,
Crumlin Dublin 12, Ireland
To the Editor.—
Powers et al1 examined the role of behavioral therapy to increase energy intake in young children with cystic fibrosis. A behavioral approach to increase intake in children with cystic fibrosis is both intuitive and attractive for parents, caregivers, and medical personnel. However, we have significant concerns about the present study and the conclusions drawn from the data presented.
The number of children included in the study is very small (n = 10). Although sample-size calculations were conducted, they were predicated on a very large difference in energy intake using a 1-sided significance test. Even allowing for the large predicted difference in energy intake, the use of a 2-sided significance test would have required a sample of 70 children (35 in each group).
An interim analysis was conducted after 10 patients were enrolled, and the trial was stopped. It is difficult to understand the rationale for this. The only evidence presented to justify stopping the trial was that 4 toddlers in the treatment group increased their energy intake by almost 4200 kJ (1000 kcal), whereas those in the control group reduced their intake, a remarkable outcome.
The use of a single height velocity at 12 months lacks the precision to provide a reliable index of current growth in short children such as those included in the study.2 A more informative presentation of the data would be to provide individual centile or z scores for the 9 children after 12 months, which would clearly demonstrate individual growth over a year.
To assess the effect of a treatment or an intervention, both the intervention group and the control group must be treated the same in all respects, apart from the intervention under investigation. Therefore, in this study those in the control group who received normal care should have been shown how to keep a food diary and asked to keep the diary each week. The contribution of keeping food diaries alone to the overall difference in energy intake between the 2 groups cannot be assessed.
It must be acknowledged that studies on the outcome of behavioral therapy are difficult to design and complete. The behavioral intervention in this study may have a role in the management of toddlers with cystic fibrosis. However, we would urge caution in interpreting the data presented by Powers et al until the results are replicated in studies of sufficient sample size to convincingly address the issue.
REFERENCES
- Powers SW, Jones JS, Ferguson KS, Piazza-Waggoner C, Daines C, Acton JD. Randomized clinical trial of behavioral and nutritional treatment to improve energy intake and growth in toddlers and preschoolers with cystic fibrosis.
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[Abstract/Free Full Text] - Voss LD, Bailey BJR, Cumming K, Wilkin TJ, Betts PR. The reliability of height measurement (the Wessex growth study).
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PEDIATRICS (ISSN 1098-4275). ©2006 by the American Academy of Pediatrics
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- Behavioral and Nutritional Treatment to Improve Energy Intake and Growth in Toddlers and Preschool-Aged Children With Cystic Fibrosis: In Reply
- Scott W. Powers
Pediatrics 2006 118: 432-433.[Extract] [Full Text]
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