Letters to the Editor
To the Editor: We appreciate the response from Dr Tormo and the opportunity to participate in scholarly discussions. We understand that the primary goal of all scientists and practitioners is to improve patient outcomes.
Dr Tormo's letter shared his clinical efforts to identify a sensitive and specific measurement to diagnose feeding intolerance (FI) in early infancy, with a timely and cost-efficient test. To clarify, our article described research efforts to identify metabolic and allostatic mechanisms associated with FI in preterm infants, which may progress into necrotizing enterocolitis (NEC). Although the concept of FI is a phenomenon that is documented in various ages and populations, the mechanisms, presentation, diagnostics, treatment plans, and secondary outcomes of FI beyond the neonatal period, as discussed by Tormo, differ from those of FI in preterm infants explored in our study. Although Dr Tormo has found success in using the fecal fat test in the population he studied, research reviews of the etiology for NEC in our population do not include fecal fat content (1–3).
We understand our results are preliminary and exploratory, and we do not suggest any measurements to use in predicting FI and NEC at this point. Our purpose was to further explore mechanisms associated with the stress response in the etiology of complications of prematurity, such as FI. To use an analogy, the downstream measure of the fecal fat test for protein intolerance is akin to monitoring fever by assessing body temperature: although body temperature diagnoses the fever, it does not speak to the underlying physiologic mechanisms producing the fever. The suite of measurements used in our study provided additional insights into the endogenous metabolic and allostatic processes that may underlie the broader diagnosis of FI in preterm infants during the neonatal period.
In conclusion, the etiology of FI that may lead to NEC remains unknown at this time and warrants further study. We appreciate Dr Tormo's suggestion to use the fecal fat test; however, we strongly disagree for the reasons listed above that this test is appropriate currently for use in preterm infants.
1. Chu A, Hageman JR, Caplan MS. Necrotizing enterocolitis predictive markers and preventive strategies. NeoReviews
2. Neu J, Walker JA. Necrotizing enterocolitis. N Engl J Med
3. Patel BK, Shah JS. Necrotizing enterocolitis in very low birth weight infants: a systemic review. ISRN Gastroenterol