Long-term kidney outcomes after COVID-19: a matched cohort study using the OpenSAFELY platform
Mahalingasivam V., Zheng B., Wing K., Parker EPK., Bhaskaran K., Carrero JJ., Jayacodi S., Jumbo E., Miah T., Gracey B., Tazare J., Santhakumaran S., Mathur R., Costello RE., Herrett E., Wen Q., Hartney T., Douglas IJ., Green A., Fisher L., Curtis HJ., Walker AJ., MacKenna B., Hulme WJ., Mehrkar A., Bacon S., Goldacre B., Williamson E., Nitsch D., Mansfield KE., Tomlinson L.
Background: COVID-19 severe enough to require hospitalisation is commonly associated with acute kidney injury. However, it remains unclear whether COVID-19 leads to long-term kidney outcomes in the broader population. Methods: We undertook a population-based, matched cohort study. With the approval of NHS England, we used primary and secondary care electronic health records from England using the OpenSAFELY-TPP platform. We compared people with and without COVID-19 using fully-adjusted, stratified, cause-specific Cox models for kidney failure, 50% reduction in kidney function, and death. Findings: Overall, all outcomes were increased after COVID-19 over the course of follow-up (HR for kidney failure 1.93 [95% CI 1.84–2.03]). Hazards of kidney failure were greatest after hospitalisation (HR 7.74 [95% CI 7.00–8.56]) and remained increased beyond 180 days of follow-up. There was no evidence of increased risk in those not hospitalised (HR 0.85 [95% CI 0.79–0.90]). Increased kidney failure was more pronounced in black ethnicity (HR 4.50 [95% CI 2.92–6.92]) compared to white ethnicity (HR 1.82 [95% CI 1.71–1.94]). Amongst those hospitalised with COVID-19, there was no attenuation of kidney failure between the first wave (HR 8.74 [95% CI 6.88–11.08]) and the Omicron wave (HR 8.36 [95% CI 6.81–10.27]). Interpretation: We observed increased long-term kidney outcomes in people hospitalised with COVID-19, as well as notable ethnic differences. Our results suggest strategies to minimise severe COVID-19 should continue to be optimised among vulnerable groups, and that kidney function should be proactively monitored after hospital discharge. Funding: National Institute for Health and Care Research.