Letters to the Editor
To the Editor: With interest we read the article by Di Pace et al, which describes esophageal motility patterns in healthy children and children with gastroesophageal reflux (GER) as assessed by multichannel intraluminal impedance (MII) (1). We, however, believe that the term “healthy children” is used inappropriately because all of the included patients underwent a 24-hour pH-MII study for the evaluation of GER symptoms and consequently are not healthy. The authors have grouped children into a healthy control group and a GER group, yet the exact criteria for this selection remain undefined. Identification of patients with GER was presumably based on adult normative data; however, these data are not transferable to children.
Patients with nonacidic reflux were excluded from the study, whereas pediatric studies have shown that nonacidic GER episodes are important in terms of the number of GER episodes and symptom association (2–4). Furthermore, compared with previous literature, the presented data suggest heavy selection because there is a substantially lower number of GER events (2–4).
In addition, data should be interpreted with caution, given the statistical tests used and the reporting thereof; for instance, in Table 1, it is not surprising that all of the parameters are statistically different because patient grouping was based on these criteria.
We believe that the conclusion drawn, stating that the data presented can serve as a reference value for healthy children, is not supported by the data.
1. Di Pace MR, Caruso AM, Catalano P, et al. Evaluation of esophageal motility using multichannel intraluminal impedance in healthy children and children with gastroesophageal reflux. J Pediatr Gastroenterol Nutr
2. Lopez-Alonso M, Moya MJ, Cabo JA, et al
. Twenty-four-hour esophageal impedance-pH monitoring in healthy preterm neonates: rate and characteristics of acid, weakly acidic, and weakly alkaline gastroesophageal reflux. Pediatrics 2006; 118:e299–e308.
3. Pilic D, Frohlich T, Noh F, et al. Detection of gastroesophageal reflux in children using combined multichannel intraluminal impedance and pH measurement: data from the German Pediatric Impedance Group. J Pediatr
4. Van Wijk MP, Benninga MA, Omari TI. Role of the multichannel intraluminal impedance technique in infants and children. J Pediatr Gastroenterol Nutr 2009; 48:2–12.