The main treatment options for hyperthyroidism are antithyroid drugs, radioactive iodine (RAI) and surgery. Each treatment type offers advantages and disadvantages so there has been little agreement on preferred treatment type. In 2019, this changed when the National Institute for Health and Care Excellence guidance on the assessment and management of thyroid disease stated clinicians should ‘Offer RAI as first-line definitive treatment with Graves’ disease unless antithyroid drugs are likely to achieve remission.’

What motivated you to conduct this research? 

 I was diagnosed with Graves' disease and it seemed very dramatic at the time with a racing heart, night sweats and sudden loss of weight. Luckily I was referred to an excellent team who helped bring the condition quickly under control and explained that the best long-term course of action was definitive treatment with radioactive iodine. Because I work in a research group with access to UK Biobank data - a rich resource of information including around half a million people, aged between 40 and 69 years old and living in the UK - I was curious to find out more, especially as treatment by medication already seemed very effective.

Why was the study needed?

NICE changed their guidance in 2019, and issued a call for further research at that time. Statistical investigations are challenging in medical fields, because there can be a lot of variability in the people who are recruited, especially in observational studies. This often means that a single study or report or dataset will be insufficient for definitive conclusions, so more researchers looking at different datasets can help to reach a well-founded consensus view.  

What did it set out to do?

The research had a simple goal - to assess whether those people with hyperthyroidism and who had been recruited to the UK Biobank study, which has been running in the UK since 2006, showed any evidence of increased risks (from health conditions or in terms of mortality) when compared by treatment type, or when compared with a control group of people without hyperthyroidism. We also looked at biomarkers in peripheral blood, to see if any showed long-term signs of dysregulation by the different treatment types. 

How was the analysis carried out?

Our research group, led by Professor Geifman, already had approved access to UK Biobank data for biomarker research. This allowed us to make a good start, but as with any large health dataset, it isn't always easy to construct a good test population! We had to select controls from the UK Biobank with which to compare people with hyperthyroidism, and that meant making sure that they were matched for as many other variables as possible, like age or smoking status, so that our analysis wouldn't be biased. The data also required a lot of cleaning, as data aren't always collected in the exact format needed. Once that part was done we were able to conduct the statistical analysis, and then compare and contrast our findings with existing literature in the field, importantly also taking into account the clinical experience and knowledge on the team.

Who was involved in the analysis?

 The analysis was done by our bioinformatics team at the University of Surrey, comprising me, Kris Elomaa and Professor Nophar Geifman. We were also lucky enough to work with Professor Simon Pearce and Dr Earn Gan, clinicians who specialise in endocrinology including thyroid disorders. It was very much a team effort!

What were your findings?

Our findings were twofold. First, we found no evidence of risks of any additional long-term health conditions from radioactive iodine treatment, or of significant changes to blood chemistry. That was obviously reassuring and consistent with the NICE guidance. But we also found that none of the treatments - whether definitive or by medication - seemed to completely eliminate potential complications from hyperthyroidism, like atrial fibrillation or osteoporosis. That means even after successful treatment, watching out for those complications is important for anyone who has suffered from hyperthyroidism, and as a result I now make extra sure to take my calcium and Vitamin D supplements as recommended by my GP! 

Were there any limitations?

The main limitations were those facing any analysis done with big data - there can be so many confounding factors that aren't obvious, like people being more likely to volunteer for studies like the UK Biobank if they are already interested in health issues. That might mean the study population has a bias in it compared to the true overall population. That can't be avoided, and is why researchers need to build on each others' work to take account of as many studies as possible, in case one turns out to be an outlier.

What further research or change to care do you think is needed in light of your findings?

 Overall, the research was consistent with evidence from elsewhere, and reassuring about the use of radioactive iodine, so thankfully we didn't find anything to contradict existing care regimens.

What role did the BTF play in helping you set up your research?

The BTF was crucial in the work. At the outset, all I knew was that I had Graves' disease and wanted to know more, and that the UK Biobank might be a way to investigate the condition. The BTF put me in touch with Prof Pearce and Dr Gan, both of whom were fantastic colleagues to work with and made the whole project possible.

And, finally, has your research helped you to reach a decision on your treatment?

Initially, I elected to control it with medication. While carrying out the research, my Graves' disease has gone into remission, and treatment by radioactive iodine is best done during active hyperthyroidism. Having seen the results, I now feel a lot more comfortable about the safety of radioactive iodine, and the next time I have an episode, I will definitely be taking that option.

Read the full study