Because many people with reduced kidney function do not experience pain or other symptoms, “what’s really important is that people realize that the risk is there and that physicians caring for post-Covid patients really pay attention to kidney function and disease,” he said.
The two sets of patients in the study differed, in that members of one group had all been infected with Covid and members of the other group may have had a variety of other health conditions. Experts cautioned that there were limitations to the comparisons.
The researchers tried to minimize the differences with detailed analyses that adjusted for a long list of demographic characteristics, pre-existing health conditions, medication usage and whether people were in nursing homes.
Another limitation is that patients in the V.A. study were largely male and white, with a median age of 68, so it is unclear how generalizable the results are.
One strength of the research, experts said, is that it involves over 1.7 million patients with detailed electronic medical records, making it the largest study so far on Covid-related kidney problems.
While the results most likely would not apply to all Covid patients, they show that for those in the study, “there’s a pretty notable impact on kidney health in survivors of Covid-19 over the long term, particularly those who were very sick during their acute illness,” said Dr. C. John Sperati, a nephrologist and associate professor of medicine at Johns Hopkins, who was not involved in the study.
Other researchers have found similar patterns, “so this is not the only study suggesting that these events are transpiring after Covid-19 infection,” he added.