The dietetic practice of prescribing amino acid-based formulas in paediatrics patients without cow's milk allergy: A single centre retrospective study

Background & aims

Although there is a comprehensive pathway for prescribing amino acid-based (elemental) formulas (AAF) in paediatric patients with cow's milk allergy (CMA), there is a paucity of evidence-based practice for prescribing AAFs in patients without CMA. Gastrointestinal symptoms are some complications that can occur in enteral tube-fed patients, to mitigate these symptoms an AAF may be prescribed. AAFs contain macronutrients that have been enzymatically hydrolysed, requiring minimal digestion and promoting optimal absorption. The primary aim of this retrospective study was to ascertain the dietetic practice of prescribing AAFs to enteral tube-fed paediatric patients without CMA. Secondary outcomes measured weight change at 1 month and 6 months after AAF was prescribed and the incidence of hypophosphatemia at 6 months.

Methods

This is a single-centre, retrospective review of paediatric patients prescribed an AAF at a tertiary paediatric hospital between July 2023 and July 2024. Ethical approval was granted by ANONYMISED Audit, Quality Improvement and Service Evaluation Committee: registration number GOSH2024/3834. Inclusion criteria were patients aged between 0 and 16 years old who had been prescribed an AAF as part of their enteral nutrition, providing at least 80% of their estimated energy requirements for any condition other than allergic disease. Exclusion criteria were patients with confirmed immunoglobulin (Ig)E or non-IgE mediated CMA or multiple food allergies, eosinophilic gastrointestinal disease, and Food protein-induced enterocolitis syndrome. Data were collected on demographics, anthropometrics, feed regimens, gastrointestinal symptoms, proton pump inhibitor use and serum phosphate concentration.

Results

203 children were prescribed an AAF during the data collection period, of these, 154 of 203 (76%) patients had no allergies. Patients with gastrointestinal symptoms were the most common reason for commencing an AAF, 76 of 154 (49%) patients. The median age of patients prescribed AAF was 5.5 (IQR 1.3–9.8) years old. Patients displaying upper or lower gastrointestinal symptoms were the most common reason dietitians prescribed an AAF, 76 of 154 (49%) patients. 44 of 154 (28%) patients prescribed an AAF had a neurological impairment as a primary diagnosis. Dietitians prescribed AAFs as a first-line formula to transition patients off parenteral nutrition in 26 of 154 (17%) patients. 23 of 154 (15%) patients were prescribed an AAF after developing mucositis post high-dose chemotherapy. AAF was also prescribed in patients post cardiac and gastrointestinal surgery, protein-losing enteropathy, and gastrointestinal dystonia. The mean weight-for-age Z-score significantly improved in patients prescribed AAF from -3.7 (1.6SD) at baseline to -2.5 (1.5SD) at 6 months (P-value 0.001). After 6 months of receiving an AAF, there was no increased probability of hypophosphatemia in patients prescribed proton pump inhibitors. (P-value 0.84).

Conclusions

This single-centre retrospective study found that paediatric dietitians reserved the prescription of AAFs for patients with complex neurological and gastrointestinal conditions. The most common reason for dietitians to prescribe AAFs was to mitigate upper and lower gastrointestinal symptoms in patients already established on enteral formulas. This review found that medically complex patients receiving AAFs for 6 months achieved expected weight gain while under the supervision of a dietitian. Our study was unable to substantiate an increased probability of hypophosphatemia in patients prescribed proton pump inhibitors and an AAF. All paediatric patients with complex medical conditions who need long-term enteral nutritional support require close nutritional monitoring.