Prevalence of HSP in England and Northern Ireland

One of the presentations after the 2024 UK HSP Support Group AGM covered the epidemiology and prevalence of HSP in England and Northern Ireland, focussing on mental health outcomes. This was presented by Harini Jeyakumar, who completed the study for her dissertation for her Masters in Public Health.

She used a dataset containing anonymous GP data from England and Norther Ireland covering the period 2000 to 2021. She used the dataset to identify people who have a diagnosis of HSP, but the dataset does not include any genetic data.

To compare the health effects of people with HSP she created a control group of people who did not have HSP, but who were otherwise matched for age, gender and location. The dataset is growing as data is added, and at December 2023 covers 24% of the population.

The overall dataset used contains 31.3 million people, and from this there are 1455 cases of HSP. This gives an overall prevalence of 4.65 people per 100,000 having HSP. There were slightly more males (58%) than females (42%) in the group, with most being middle-aged or older.

Although there were 27% without ethnicity data, most (65%) were white, with the next biggest group being Asian (6%). Geographically, people were spread fairly evenly across England, with slightly more in the South East and North West of England. Less than 1% of the people were from Northern Ireland. In terms of deprivation, the distribution was fairly even, although there were slightly more people in the higher levels of deprivation.

Harini had looked at the change in prevalence over time, in 2000 the prevalence of HSP was 2.83 per 100,000, which rose steadily over time to 6.27 per 100,000 in 2021. At the beginning of her presentation Harini had put the results of other studies up for comparison, ranging from Norway at 7.4 per 100,000 to Ireland at 1.3 per 100,000.

The mental health outcomes were also interesting. The dataset allowed pre-existing health conditions to be examined. For depression, 19% had a pre-existing diagnosis, compared with 12% of the control group. For anxiety, 12% had a pre-existing diagnosis, compared with 9% of the control group. This means that people with HSP are 74% more likely to have depression and 31% more likely to have anxiety, compared with people who do not have HSP. 

Crunching the numbers through shows that people with HSP are 57% more likely to develop depression and 41% more likely to develop anxiety. People in the more deprived areas are also more likely to develop these, as are females. Those with Asian ethnicity are less likely to develop these than people who are white, although this was a small dataset. There were a lot of interesting questions and discussion after this.

You can watch this here: https://www.youtube.com/watch?v=ARMtXWg0EOE

Regular readers will note that I have previously looked at published studies on the prevalence of HSP, back in 2011! https://hspjourney.blogspot.com/2011/08/hsp-prevalence.html. I had looked at European studies and obtained a prevalence of 2.91 per 100,000. Noting the change over time, these studies are from the period 1982 to 2009, with most in the 1990's. The prevalence Harini notes for 2000 is very similar to this at 2.81 per 100,000.

It is interesting to consider why the prevalence rate changes over time. Certainly the number of types of HSP has increased over time, and the number that are available in genetic test panels has also increased. Also, the cost of genetic testing has come down, and the availability is higher. However, there is still a diagnosis gap, with many getting a clinical diagnosis instead of a genetic one. I speculate that the awareness of HSP is increasing over time, but I also appreciate that I have a very biased view on this!

Taking the 4.65 value, with a UK population of 68.3 million, there should be some 3200 people with HSP in the UK. Allowing for the 30-40% diagnosis gap that might put the number more into the 4000's. I used this logic in 2020 in an earlier estimate: https://hspjourney.blogspot.com/2020/01/update-to-prevalence-with-hsp-in-uk.html

I was surprised that there were so few people with HSP in Northern Ireland. The population of Northern Ireland is about 3% of the population of England and Northern Ireland, and there were less than 1% of the people with HSP in Northern Ireland.

There is certainly some food for thought in this data when I wear my Support Group hat - principally:

• We ought to have a rising membership to match the rising prevalence.
• Are we known in the more deprived parts of the UK to pick up the higher mental health risks.
• Does our gender split match these findings, or are we missing a group of people.
• Do we have enough ethnicity data to explore if we are also missing out on groups of people.