OpenSAFELY, ISARIC, PHOSP: tracking consequences of COVID-19 infection across UK primary and secondary care.

While a large number of people who were diagnosed with COVID-19 have sadly died, there are still many people who survived having severe COVID. However, we know relatively little about people's experiences after this, in terms of how well they have recovered, and if they have additional healthcare needs when compared to similar people who did not have COVID-19.

There are early reports of people experiencing "long COVID" - where the symptoms of COVID persist for many weeks, and also an increased likelihood of more serious outcomes like stroke and heart attacks.

Understanding the experience of people recovering from COVID-19 better will help people and doctors to better understand the risks that they face, and to make informed choices about treatment during recovery. It will also help people who make decisions about providing healthcare services to determine what kind of services are needed, how many people they might have to treat and for how long after people have COVID-19 they might be required.

Ultimately this could help to improve the outcomes of patients - helping them to recover to a greater extent, and/or more quickly.

The OpenSAFELY project was set up at the beginning of the pandemic to provide urgent information on COVID-19. It contains information from the primary care (general practice) records of 40% of the English population. ISARIC contains detailed hospital records for people who were admitted to hospital with COVID-19.

PHOSP contains data on symptoms and laboratory tests for people who were hospitalised with COVID-19 but were later discharged. These three data sources will be linked together to provide a much more powerful resource, where we can reliably determine what happens to COVID-19 patients after they are discharged from hospital.

Specifically, we will measure the occurrence in COVID-19 patients of many different diagnoses, symptoms and other healthcare activities like treatments and lab tests. We will compare these to how often they occur in similar patients who did not have COVID-19, and will determine what sort of things might influence how often they occur. For example, people who are older or those with previous medical conditions might be more likely to experience adverse outcomes during their recovery.

We will describe in detail which patient outcomes are most likely to occur, which patients are most likely to get them and how long the risk lasts for. We will then measure the impact of the risks that we measure on healthcare services to help plan services in future.