Registry Research in Denmark
My name is Lars Folkestad. I am an associate professor and staff specialist at the department of endocrinology at Odense University Hospital. There I am part of the team that follows and cares for adults with OI. We are aiming towards a multi-disciplinary approach to our outpatient OI clinic visits, but most of our efforts have been haltered due to this horrendous COVID situation.
Which research projects related to OI are you currently working on?

Funding clinical research related to rare diseases can be difficult in today’s climate. We are currently trying (and failing) to finance a nationwide clinical study to elaborate on the extra skeletal aspects of OI. Luckily, we have been able to fund epidemiological studies using the Danish health registers. I am currently working with these data and hope to be able to share them with you shortly. Denmark is a rather small country and adult OI care is situated at 3 University centres. We are very set on collaborating and sharing knowledge to ensure the best care of our patients. Did you read the interviews with Emilie and Marie-Louise? I cannot stress how impressed I have been working with them.
Why is there so much registry research coming out of Denmark?
The Danish health registers are unique data sources intended for governance – where almost everything is registered about everybody all the time. Furthermore, data collection is mandatory by law and for the most part done automatically using the clinical database that we use in everyday work in all aspects of the society from schools to hospitals. In Denmark every inhabitant is given a unique personal identifier that can be used for record and register linkage. This makes it possible for long-term follow-up literally without any missing data. The coverage of the registers is above 99%. Time and time again they have been shown to be valid regarding accuracy of the data. During my PhD studies, one of my supervisors – Professor Bo Abrahamson – introduced me to the method. We then worked together on using the registers for rare bone diseases such as OI. We have been lucky to be able to update our data and have many more questions to answer.
What are the benefits and limitations of registry research as a method?
The benefits, if you ask me, are obvious. We are dealing with a rare condition and collecting clinical data on all patients in Denmark would be difficult to say the least. Using the registers, we have nationwide and population-based data on for example contacts to the health care system. This can be used as markers of diseases associated with OI, and we can even compare the OI population with the general population if this is of interest.
The limitation of the registry data is that it’s just that, register based. We have little or no clinical data. For example, I can tell you what the risk of asthma is in the OI population and drug use related to asthma, but I cannot tell you anything about pulmonary function.
Furthermore, the clinical spectrum of OI is as you know quite wide or in other words OI is not just OI. The register data will give us information about who has OI but not what genetic background or clinical severity. We are however working to overcome this limitation, but we are not there yet.
Any messages to the OIFE Magazine readers?
I hope that 2022 is the year where we get to meet up, discuss and develop new ideas for new projects face to face. I really hope that the International OI conference will take place in Sheffield this year. Zoom and other online meetings are great and a way to stay updated and keep in touch. But nothing beats sitting down talking to people, after a long day at a conference. This is where the best networks are formed, and the best ideas come to life. Fingers crossed. See you all soon!
This interview was first published in OIFE Magazine 4-2021.