Project #169:
Long-term kidney outcomes after SARS-CoV-2 infection (Project continuation of approved project no 78)

Around a third of people admitted to hospital with COVID-19 develop kidney damage (known as acute kidney injury or AKI). While AKI is often recoverable, it can sometimes lead to worsening of long-term kidney function and in some cases, permanent kidney failure requiring long-term dialysis or a kidney transplant. The complications caused by long-term kidney damage exert considerable stress on the NHS and it is important that we know what to expect to be able to ensure that services are planned with sufficient capacity to cope. For example, growing numbers of people requiring dialysis will require investment in the workforce and infrastructure. Our research plans to investigate what happens to long-term kidney function after COVID-19 using electronically coded GP records combined with hospital records from England.

Our study will include adults without kidney failure to begin with (i.e. those not on dialysis or a kidney transplant). We will compare people with and without COVID-19 for differences in the rates of the following kidney outcomes:

1. New kidney failure,
2. 50% or more reduction in kidney function from before,
3. Further AKI.

We will be able to determine whether outcomes vary based on the severity of COVID-19, based on time (e.g. during peaks, after widespread use of effective anti-COVID-19 drugs), and based on levels of vaccination. We will account for factors such as age, sex, ethnicity, socioeconomic deprivation, smoking, BMI, and pre-existing medical problems such as diabetes.

As kidney failure is relatively rare at the general population level, very large studies are needed to be able to investigate whether or not a group is at increased risk compared to other groups. Because of the size of the population in OpenSAFELY, we will be uniquely placed to be able to detect differences in this outcome due to COVID-19.