“Cases of the painful skin condition eczema have risen more than 40 per cent in just four years”, The Daily Telegraph reported. It said the increase could be partly due to the use of soap and detergents, as well as better awareness and diagnosis of the disease. A rise in prescriptions of eczema drugs corresponded with the rise in diagnoses during this time.
The news story is based on a study that looked at eczema diagnosis and treatment at GP surgeries in England between 2001 and 2005. It found an increase of about four new cases of eczema per 1,000 people over this time. This represents an approximate increase of 40%.
Unfortunately, this type of study cannot pinpoint the reason for the increase in cases of eczema. This could reflect a real increase in the disease, or increasing clinician awareness (improved diagnosis), or increasing patient awareness (patients more likely to visit their GP). The researchers acknowledge that there are important public health implications whatever the cause, and they call for further research.
Where did the story come from?
Dr Colin R. Simpson and colleagues from the University of Edinburgh, the University of Manchester and the University of Nottingham carried out this study. It was funded by the NHS Health and Social Care Information Centre. The study was published in the peer-reviewed Journal of the Royal Society of Medicine .
What kind of scientific study was this?
This time-series study investigated the changing rates of eczema in England between 2001 and 2005. The researchers were also interested in the health behaviour of patients with eczema, in terms of how many times they visited their GP and what treatments their GPs prescribed.
The researchers obtained their data from a database called QRESEARCH. This database holds the records of over 9m patients from 525 GP surgeries in England. For this analysis, the researchers excluded people with incomplete data (i.e. temporary residents, newly-registered patients and those who joined, left or died during the year of study).
They calculated the number of patients with a new case of eczema for each year between 2001 and 2005 (i.e. annual incidence), and the number of people with eczema ever recorded on at least one occasion (lifetime prevalence). Estimated numbers of eczema prescriptions (emollients, topical steroids and psoriasis and eczema treatments) were also recorded.
The rates of disease and prescription results were standardised by age and gender. Standardisation of rates takes into account the difference in terms of age and gender between this study population and the population of England halfway through each of the study years. Using this method, the researchers could estimate the number of people with eczema in England.
What were the results of the study?
The study found a 42% overall increase in the rate of new eczema cases each year. In absolute terms, this was an increase from about 10 cases per 1,000 in 2001 to 14 cases per 1,000 in 2005 (four new cases per 1,000 people over five years).
The study also found an increase in age-sex standardised lifetime prevalence of eczema of 48.2%. This means that the number of people diagnosed with eczema at some point in their lives increased from 77.78 people in every 1,000 in 2001 to 115.26 in every 1,000 people in 2005. This signifies an increase of about 38 people with eczema in every 1,000 people between 2001 and 2005. The increases were found in most age groups and both genders.
On average, the eczema patients consulted a GP four times a year, and prescriptions for eczema medications increased by about 57%. An estimated total of 13,700,000 were prescriptions issued in 2005.
What interpretations did the researchers draw from these results?
The researchers conclude that the incidence and lifetime prevalence of eczema is increasing. They say that corresponding increases in the number of eczema prescriptions issued to people in England have also been observed.
What does the NHS Knowledge Service make of this study?
Overall, this study shows an increase in the prevalence of eczema over time. The strengths of this study include the use of a large, nationally representative dataset that used standard data collection methods at the GP surgeries. It also relied on a clinical diagnosis of eczema rather than just using patients’ self-reported diagnoses.
The researchers discuss their findings in relation to other studies, some of which had the same finding while others had contrasting results. Importantly, they go on to discuss the possible reasons for the increase in eczema diagnosis in this database. Broadly, these fall into the following categories:
- A real increase in allergic disease.
- An increase in clinicians’ awareness of these conditions. In other words, the identification and recording of eczema has improved without an actual increase in the number of eczema cases.
- An increase in patient’s (or parents of patients) awareness of eczema. This would lead to increasing presentation of the condition to GPs and their prescribing of treatment.
Unfortunately, time trend studies such as this cannot pinpoint the reason behind the increase in cases of eczema. The researchers conclude that “whether these findings reflect a genuine increase in the incidence of eczema, improved awareness, diagnosis and recording in primary care, or, perhaps most plausibly, a combination of genuine increases and improved identification and recording, is a question with important public health implications”.
Eczema is common, and this study successfully highlights the importance of monitoring trends in disease incidence. More research will be needed to determine the cause for the increase in numbers.
Analysis by Bazian
Edited by NHS Website
Links to the headlines
BBC News, 24 March 2009
The Daily Telegraph, 24 March 2009
Links to the science
JRSM 2009; 102: 108-117