Acute kidney injury linked to later dementia
SAN DIEGO –
Dr. Jessica B. Kendrick
That’s according to a new study offering more evidence of a link between kidney disease and neurological problems.
“Clinicians should know that AKI is associated with poor long-term outcomes,” said lead author Jessica B. Kendrick MD, associate professor of medicine at the University of Colorado, Aurora. “We need to identify ways to prevent these long-term consequences.”
The findings were presented at Kidney Week 2018, sponsored by the American Society of Nephrology.
According to Dr. Kendrick, the acute neurological effects of AKI are well known. But no previous studies have examined the potential long-term cerebrovascular complications of AKI.
For the new study, Dr. Kendrick and her colleagues retrospectively analyzed 2,082 hospitalized patients in Utah from 1999 to 2009: 1,041 who completely recovered from AKI by discharge, and 1,041 who did not have AKI.
The average age was 61 years, and the average baseline creatinine was 0.9 ± 0.2 mg/dL. Over a median follow-up of 6 years, 97 patients developed dementia.
Those with AKI were more likely to develop dementia compared with the control group: 7% vs. 2% (hazard ratio, 3.4; 95% confidence interval, 2.14-5.40).
Other studies have linked kidney disease to cognitive impairment.
“There are a lot of theories as to why this is,” nephrologist Daniel Weiner, MD, of Tufts University, Boston, said in an interview. “It is most likely that the presence of kidney disease identifies individuals with a high burden of vascular disease, and that vascular disease, particularly of the small blood vessels, is an important contributor to cognitive impairment and dementia.”
That appears to be most notable in people who have protein in their urine, Dr. Weiner added. “The presence of protein in the urine identifies a severe enough process to affect the blood vessels in the kidney, and there is no reason to think that blood vessels elsewhere in the body, including in the brain, are not similarly affected.”
As for the current study, Dr. Weiner said it could support the vascular disease theory.
“People with vulnerable kidneys to acute injury also have vulnerable brains to acute injury,” he said. “People who get AKI usually have susceptibility to perfusion-related kidney injury. In other words, the small blood vessels that supply the kidney are unable to compensate to maintain sufficient blood flow during a time of low blood pressure or other systemic illness.”
That vulnerability “suggests to me that small blood vessels elsewhere in the body are less likely to be able to respond to challenges like low blood pressure,” Dr. Weiner explained. “If this occurs in the brain, it leads to microvascular disease and greater abnormal white-matter burden. This change in the brain anatomy is highly correlated with cognitive impairment.”
How can physicians put these finding to use? “These patients may require more monitoring,” Dr. Kendrick said. “For example, patients with AKI and complete recovery may not have any follow-up with a nephrologist, and perhaps they should.”
Moving forward, she said, “we are examining the association of AKI with cognitive dysfunction in different patient populations.” Researchers also are planning studies to better understand the mechanisms that are at work, she said.
The National Heart, Lung, and Blood Institute funded the study. The study authors had no disclosures.
SOURCE: Kendrick JB et al. Kidney Week 2018. Abstract TH-OR116.
