More intriguing than helpful

A recent study reports that a pH-impedance (pH-MII) may help identify children with allergen-induced gastroesophageal reflux disease (GERD) after exposure to cow’s milk (J Pediatr 2012; 161: 476-81).  The study population included 17 children (average age 14 months) with a clinical diagnosis of cow’s milk allergy (CMA) who had responded to an elemental diet.

Given the limitations of the study, it is hard to take seriously the conclusions of the authors that in “selected cases of children with CMA in whom GERD is suspected” pH-MII “should be considered as part of diagnostic workup.”

The limitations:

  • CMA diagnosed clinically based on response to dietary therapy
  • GERD diagnosed based on Infant GER Questionnaire, though authors acknowledge that “we are aware that no symptom or cluster of symptoms have been shown to reliably predict the diagnosis of GERD”
  • Statistically-significant findings only for weakly acidic reflux which was induced on second day after switching from elemental formula to cow’s milk
  • No endoscopic correlation of mucosal disease or exclusion of eosinophilic esophagitis
  • Small number of patients

I cannot see how obtaining a pH-MII study would offer a meaningful benefit to these patients; though, it is intriguing that one potential measure of clinical deterioration like increased weakly acid episodes can be detected when these patients are challenged with cow’s milk.

Some related blog entries:

Impedance recommendations from PIG

Gastroesophageal Reflux: I know it when I see it

Guidelines for Eosinophilic Esophagitis

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