Latest evidence on the risk of Covid-19 for kidney patients
Following the statement we published on Tuesday 14 December about kidney patients needing to be extra vigilant we now have the results from a study that was published* on Thursday 16 December. This showed that amongst people who had been double vaccinated, those with chronic kidney disease, on dialysis or who had had a kidney transplant were at much higher risk of being hospitalised with Covid-19, or of dying from it than those in the general population. Delta was the dominant variant for the majority of this study.
Even so, vaccination and especially with boosters, third doses and fourth dose boosters where advised, provide better protection from infection, hospitalisation and death than not being vaccinated. With uncertainties around Omicron, it is recommended that kidney patients avoid exposure to Covid-19 wherever possible, through wearing masks, working from home if possible, limited socialising (outdoors or in well-ventilated areas) and avoiding crowds.
This is tough news to pass on to kidney patients, who have had a very difficult couple of years, since Covid-19 restrictions began. However, it’s important to give you as much information as possible to help you make decisions, particularly over the festive period. If you are anxious or need more help, please contact your GP or specialist kidney team.
This latest data is now being used to highlight the vulnerability of kidney patients and to lobby for priority access to fourth Covid-19 vaccinations and newer monoclonal antibody and oral anti-viral treatments.
About the study
The OpenSAFELY study included over 15 million people in England who had already received two doses of Covid-19 vaccine. It counted the number of people who had a positive Covid-19 test despite being vaccinated, from two weeks after the second vaccination until 01 November 2021. It also counted those who were admitted to hospital or an intensive care unit for Covid-19, and those who died with Covid-19 during that time.
The data used different groups, for example, age, ethnicity and sex, and also separated people with different medical conditions which were known to put them at increased risk from Covid-19.
Because the time from being fully vaccinated to the end of the study varied for each person, the data was standardised to give rates of occurrences “per thousand person-years”. This allowed the rates for each group studied to be compared on a more level playing field.
Results of the study
The study showed that two Covid-19 vaccinations were not sufficient to prevent people catching Covid-19. There were around 98 infected people per ‘1,000 people-years’ (1,000 people followed up for a year after vaccination). It did confirm that overall, the risk of dying was very low – around 0.66 deaths per 1,000 people-years. This was unsurprisingly lower for younger people (0.03) and rose to around 3.35 for those 80 years old and above.
Covid-19 Infection rates
Kidney patients were given their own analysis in the study.
- Those with chronic kidney disease (CKD) Stages 3a-4 were less likely than those without CKD to get infected with Covid-19. The study wasn’t designed to explain this, but it might be that those with CKD were taking more care not to be exposed to Covid-19.
- CKD and Stage 5 dialysis patients were more likely to be infected with Covid-19 (once age had been taken into account) and this may reflect increased susceptibility due to a naturally reduced immunity, or increased exposure for dialysis patients going for treatment.
- Transplant patients were also more likely to catch Covid-19 and this may reflect their reduced resistance to Covid-19 because of immunosuppression, despite also being more likely to reduce their exposure or shield where possible.
Hospitalisation and Critical Care
Kidney patients were also more likely to be admitted to hospital or receive critical care (in an intensive care unit). For example, there were about 31 hospital admissions per 1,000 person-years for CKD Stage 5 patients compared to around two for non-CKD patients (although a small amount of this increase was explained by differences in age between the two groups). Dialysis and transplant patients also had similarly high rates of hospital admission. It may be that some of these admissions were precautionary, to ensure that kidney patients got the best possible care, but it is not possible to know if that was the case from the data.
Deaths from Covid-19
Sadly, there were increased rates of Covid-related deaths amongst kidney patients (rates of 10-14 per 1,000 person years) compared to people without kidney disease (0.43). Again, some of this increase is due to differences in age between the groups but, even so, those with CKD Stages 4-5, dialysis patients and transplant recipients had substantially higher rates.
|Whole study population (~15 million)||98.02||2.72||0.19||0.66|
|Dialysis||No previous transplant||107.13||26.22||3.59||8.33|
|Kidney Transplant||No previous dialysis||128.40||33.07||8.23||10.00|
|Kidney Transplant||Previous dialysis||142.92||40.91||11.53||11.45|
|Other organ transplant||126.86||31.67||7.42||10.45|
Note 1: these rates (expressed per 1,000 person-years) are approximate (see Table 1, Table 2 and Supplementary Table S1 for full data with confidence intervals).
Note 2: Because the data in the different columns come from different sources, it is not possible to compare data directly between columns (for example, work out accurate ‘deaths per hospital admissions’ or ‘case fatality’ rates).
* This paper is currently a preprint. A preprint is an academic paper that has been shared publicly but has not yet been published in a journal (which means it has not been subjected to ‘peer review’ — the process where independent scientists assess the quality of the work).