The UK is one of the best countries in the world for carrying out observational pharmacoepidemiologic studies

The UK healthcare system has many qualities which make it ideal for carrying out observational research.

Observational research is complementary to clinical trials due to multiple well-documented reasons, such as the shortfall of clinical trials to include only healthy, young participants, excluding special patient groups such as the elderly, pregnant women, children, and people with comorbidities or taking concomitant medications. Under normal clinical practice, these medicines are often used by patients who were excluded from clinical trials. Medicines can have different effects related to both safety and effectiveness in different patient groups.

Post-authorisation observational studies monitoring safety and effectiveness are required for new products, new indications, new populations, and new formulations. These studies are both medically merited and required by regulatory authorities. The UK is one of the best places in the world for conducting observational studies, including pharmacoepidemiological studies.

1) The NHS allows longitudinal follow-up
People in the UK are usually assigned a National Health Service (NHS) general practitioner (GP) who provides medical services for them until the patient leaves the practice. When the patient leaves a practice, their medical record follows them to their next GP. As patients have one medical record for life, long-term follow-up (which some affectionately call “from the cradle to the grave”) is possible. This means that the UK population also lends itself to multiple epidemiological study designs. Linking exposure to medicines with health outcomes is relatively easy in the UK compared to many countries.

2) Detailed medical records
Data which may be useful for research is routinely collected during GP consultations and recorded in the medical record. Details on the following factors are available:

• Demographics
• Prescribed medications
• Vaccination history
• Health screening
• Diagnosed medical conditions
• Potential confounders (such as body mass index, ethnicity, and in some cases smoking status)
• Hospital contacts (attendance to A&E, hospital clinics and admissions)
• Results of investigations

All health data is stored in one single medical record per patient, as described above.

3) Availability of medical records for research purposes
Anonymised medical data for the UK population are available (subject to necessary approvals) for research purposes via initiatives such as Clinical Practice Research Datalink (CPRD), Q Research, THIN, and OpenSAFELY. Study populations from these data sources are largely representative of the wider population of the UK. Linkage to other databases, including hospital admissions and Office for National Statistics (ONS) death data, is possible.

The DSRU has been working with these data sources for many years, conducting research into the safety of many important medicinal products. We are currently undertaking observational research into the safety of all COVID-19 vaccines available in the UK. In addition, we are conducting a large number of studies on a range of drugs which are used both in hospitals and in the community. We have a team of medics, epidemiologists and scientists who understand the health system of the UK and have experience working with these detailed health records. Knowledge of the healthcare system of any country is key to high quality pharmacopepidemiological studies.

Conclusion
The reasons outlined above are why the UK has and will continue to be a leader in observational research. There is a wealth of data available and leading pharmacoepidemiology institutes, such as DSRU and others, are available to carry out the research.