Time Trends, Regional Variation and Associations of Low‐Allergy Formula Prescribing in England.

Background: Cow's milk allergy (CMA) overdiagnosis appears to be increasing and is associated with excessive low‐allergy formula prescription. We evaluated recent trends and regional variation in low‐allergy formula prescribing for CMA in England, and assessed potential risk factors for higher prescribing rates. Methods: Data on national and regional prescribing of low‐allergy formulas were extracted from England's electronic prescription database using R. Region‐level factors were evaluated for potential associations with regional low‐allergy formula prescription rates using multivariate linear regression. Analysis of national prescribing trends covered 2007–2023, analysis of regional variation and region‐level factors examined 2017–2019, prior to a re‐organisation of the regional healthcare structure in England. Results: Low‐allergy formula prescribing increased from 6.1 to 23.3 L per birth nationally, between 2007 and 2023. Regional prescribing rate varied from 0.8 to 47.6 L per birth in 2017–2019. We found significant associations between regional low‐allergy formula prescribing rate and regional prescribing rates for milk feed thickeners Gaviscon Infant and Carobel Instant (β = 0.10, p < 0.01), and for other anti‐reflux medications used in young children (β = 0.89 p < 0.01). Inconsistent associations were seen with prescribing junior adrenaline auto‐injectors and oral antibiotics. A model including these four variables accounted for 37% of regional variation in low‐allergy formula prescribing rate. Region‐level socio‐economic deprivation, CMA guideline recommendations and paediatric allergy service provision were not associated with low‐allergy formula prescribing. Conclusions: Low‐allergy formula prescribing in England is increasing, varies significantly by region and is consistently associated with prescribing rates for milk feed thickeners and other anti‐reflux medication for young children. Community prescribing behaviours may be important determinants of CMA overdiagnosis. [ABSTRACT FROM AUTHOR]