Using data from The Health Improvement Network (THIN) database for the period 2000–2012, the researchers found that 23,837 children aged 0–17 years were deemed high risk by their GPs, and were prescribed 98,737 AAI devices.
These figures equate to 4.67 high-risk children (95% CI 4.66–4.69) and 19.4 devices (95% CI 19.2–19.5) per 1000 person–years.
About 50% of the 'high-risk' children were recorded by their GPs as having egg, nut, seafood, insect venom allergy, or previous anaphylaxis.
‘Given that only half of the "high-risk" children were noted as having a previous relevant allergy or anaphylaxis diagnosis, the rationale for prescribing is, in many cases, unclear,’ said Lavanya Diwakar, lead author of the study and honorary consultant in immunology at Queen Elizabeth Hospital in Birmingham.
Sharp increase in prescribing
The study, published in the British Journal of General Practice, showed that AAI prescribing increased sharply from 2000 to 2012, with a 355% increase in the number of children prescribed devices, and a 33% increase in the number of devices prescribed per child.
Almost a quarter (24%) of the high-risk children received more than four devices in a year.
The rate of hospital admission in England for anaphylaxis increased over the study period, although mortality rates decreased.
Based on the anaphylaxis hospitalisation rate of 7 per 100,000 in 2012, the authors estimate that approximately 400 AAI devices were prescribed per child admitted to hospital. The benefits and risks of such prescribing are not clear, they say.
The increase in the number of devices being prescribed places a significant financial burden on the NHS, according to the researchers. At an average cost per device of £25.80, the estimated annual expenditure on AAIs for children was approximately £7 million in 2012.
Recent guidance from the British Society for Allergy and Clinical Immunology (BSACI) suggests that only one AAI should be issued per individual, although children may be issued with two – one for home and one for school. There are no data to suggest that the provision of more than two devices can be life-saving or provide reassurance.