Prescribing trends in Cow’s Milk Protein Allergy: a retrospective database study

Problem

Cow’s Milk Protein Allergy (CMPA) is the second most common childhood food allergy, and is thought to be increasing, with associated rising costs to the NHS. It can be divided into IgE and non-IgE mediated: IgE mediated reactions are immediate and result in histamine-related symptoms (for example urticaria and angioedema); whereas non-IgE mediated reactions are termed delayed and constitute a myriad of more non-specific symptoms, including gastro-oesophageal reflux, abdominal pain, skin changes and constipation. Management of cow’s milk protein allergy includes prescription of a specialised formula; historically this was soya-based, but current guidelines suggest the majority of children should be prescribed an extensively hydrolysed formula, with amino-acid based as second-line. We aim to describe prescribing trends for Cow’s Milk Protein Allergy (CMPA), including the proportion of the three formula types, for the years 2007-2017, in a bid to determine whether this is an increasing public health problem.

Approach

We identified all formula prescribed for CMPA between the years 2007-2017 and used publically available yearly prescribing datasets, and population data form the Office of National Statistics, to calculate prescribing rates per 1000 of population under 2. We report how the rate of prescribing has changed, as well as the proportion of each type of formula (amino-acid, extensively hydrolysed or soya). We have also calculated the estimated cost to the NHS of these prescriptions (this cost does not take into account dispensing costs etc)

Findings

The study found that there has been a significant increase in the prescribing rate for CMPA in the past 10 years. In accordance with current guidelines, the rate of soya-based formula has declined, but there has been dramatic increases in both hydrolysed (309%) and amino acid based formula (435%). This increase comes at a substantial cost to the NHS, with the cost of formula for CMPA rising from £12.8million in 2007, to £65.2million in 2017, amounting to a 319% increase when adjusted for inflation (using the consumer price inflation (CPI) index).

Consequences

There has been a significant increase in the rate of prescribing of formula for CMPA, which now represents a growing financial burden to the NHS in prescriptions alone. Further work is needed to determine whether the increase in prescriptions is related to over diagnosis of CMPA, increased awareness of the condition by both carers and professionals, or a genuine increase in incidence.