Dialysis is a life-saving treatment that turns potentially fatal kidney diseases into manageable illnesses.
But new research finds that dialysis may also increase the risk of dementia.
According to the National Kidney Foundation, more than a half-million Americans rely on kidney dialysis to survive.
However, a new study published today in the Clinical Journal of the American Society of Nephrology (CJASN) finds that this treatment may also increase the risk of dementia and Alzheimer’s disease in older adults, particularly women and minorities.
Mara McAdams DeMarco, PhD, lead study author and an assistant professor in the Bloomberg School of Public Health at Johns Hopkins University in Maryland, told Healthline, “What we do know is that there is a greater burden of diagnosed dementia among older adults initiating dialysis than we would expect among community-dwelling older adults of the same age.”
What the study revealed
Researchers studied more than 350,000 Medicare patients on dialysis treatment, aged 66 and older, from 2001 to 2013.
About 47 percent of study participants were female and 20 percent were African-American.
Researchers say they found that the lifetime risk of being diagnosed with dementia after beginning dialysis was 19 percent for end-stage kidney disease (ESKD) patients aged 66 to 70. It rose to 28 percent for those between 76 and 80 years of age.
“This study was done because we have a long-standing interest in geriatric nephrology,” said DeMarco.
She added the goal was to better understand the incidence, risk factors, and consequences of a dementia diagnosis in older patients on dialysis.
Dr. Harold Szerlip, division director of nephrology at Baylor University Medical Center in Texas, agrees.
“While the reasons are unclear, there is considerable evidence that cognitive decline, especially loss of executive function, begins at early stages of [chronic kidney disease] and progresses more rapidly with initiation of dialysis,” Szerlip told Healthline.
Women affected more than men
According to the findings, the 10-year risk of developing dementia after beginning dialysis was 21 percent in men versus 25 percent in women.
The risk of being diagnosed specifically with Alzheimer’s disease was also higher in women.
However, Szerlip emphasized that “While there is a slight increase in CKD in women, end-stage kidney disease still tends to be more frequent in men, although we really don’t know why.”
The study authors report that a diagnosis of dementia doubled the mortality rate of dialysis patients.
“Regardless of age, sex, race, and other disease conditions, a diagnosis of dementia was associated with a two-fold risk of mortality among older adults initiating hemodialysis,” the authors wrote.
“But our findings don’t indicate that dialysis treatment itself is what’s increasing the risk of dementia and Alzheimer’s disease,” cautioned DeMarco.
Minorities have a higher risk
Hispanic and African-American dialysis patients were found to have about twice the risk of being diagnosed with dementia and Alzheimer’s disease compared to whites.
According to Szerlip, “Blacks and Hispanics also develop CKD at a higher rate than whites, possibly because they experience more obesity, more diabetes, and less access to healthcare.”
“Our study was not able to tease apart why blacks, Hispanics, or women on dialysis were more likely to be diagnosed with dementia,” added DeMarco.
Dialysis causes low blood pressure
Low blood pressure may be one reason why kidney dialysis patients experience a greater risk of dementia and Alzheimer’s disease.
Dialysis can cause low blood pressure. A 2016 study in PLOS Medicine found this significantly increases the risk of vascular dementia, which is caused by impaired blood supply to the brain.
This was the most common type of dementia that was diagnosed in the study participants.
Szerlip said, “The more rapid cognitive decline after starting dialysis could be related to episodes of low blood pressure caused by dialysis. This makes the fact that vascular dementia is more common in CKD more understandable.”
But he’s not as sure about the increased incidence of Alzheimer’s disease.
“Whether there is actually more Alzheimer’s is unclear,” Szerlip said. “This study used Medicare data, which may be inaccurate as far as a diagnosis of Alzheimer’s.”
He said this is because many Medicare doctors will list any dementia as Alzheimer’s without proving that there are actual symptoms of the disease, such as protein plaques in the brain.
Preventing chronic kidney disease
The consequences of CKD can be severe.
Besides an increased risk of developing dementia or Alzheimer’s disease, dialysis can seriously impact your quality of life.
According to the National Kidney Foundation, some side effects of dialysis include:
- low blood pressure, which can cause dizziness, nausea, and fatigue
- muscle cramping
- dry, itchy skin
Szerlip states that the best way to avoid kidney disease is by preventing diabetes, which is the biggest risk factor.
“Addressing the obesity epidemic will reduce the incidence of diabetes, which is the leading cause of kidney disease that may lead to dialysis,” he said.