SAN DIEGO -- Acute kidney injury (AKI) was tied to an increased risk for hospitalized dementia, researchers reported here.
In a group of over 2,000 individuals who were hospitalized at some point for AKI, around half were discharged having complete AKI recovery. defined as a serum discharge creatinine <1.10 times the level prior to hospital admission, according to Jessica Kendrick, MD, of the University of Colorado School of Medicine in Aurora, and colleagues.
However, these individuals who experienced a full kidney recovery still carried a nearly a 3.5-fold increased risk for developing dementia within the median 5.8-year follow-up period when compared with individuals who never had AKI (HR 3.4, 95% CI 2.14-5.40), they said in a presentation at the American Society of Nephrology (ASN) Kidney Week 2018.
Kendrick told the study adds to the existing evidence that AKI is associated with several adverse long-term outcomes. Prior data have already linked AKI with an associated increased risk for several other adverse clinical outcomes, including progression to end-stage renal disease, cardiovascular events, and acute neurological complications, she explained.
Kendrick added that the current study was undertaken because there was a lack of research that looked at whether or not AKI was tied to long-term cerebrovascular complications.
This retrospective propensity score-matched study included data on 1,041 adult individuals admitted to a hospital between 1999 to 2009 for AKI, matched with patients free of AKI. This was defined using ICD-9 codes and serum creatinine values. Individuals with a prior history of dementia were excluded from the analysis.
Among the total cohort, 97 individuals developed dementia or Alzheimer's disease during follow-up, including 7% of AKI patients with full renal recovery and 2.3% of patients without a history of AKI. These patients with a history of AKI also on average had a shorter time to dementia (5.1 years vs 6 years in matched patients).
The study's observational nature was a limitation, but Kendrick said the utilization of ICD-9 and serum creatinine values for AKI diagnosis was a strength.
ASN session co-moderator, Sarah Huen, MD, PhD, of UT Southwestern Medical Center in Dallas, asked Kendrick if her group suspected what were the underlying mechanisms driving this association. Kendrick replied that she and her colleagues are currently trying to answer that with longer-term follow-up of this cohort.
"It really might come back to vascular dysfunction...we know that that happens, and perhaps it's more long-term and permanent damage that's happening in these patients -- and then we just don't see the effects until years down the road," Kendrick said.
Kendrick suggested that "clinicians should recognize that AKI is associated with long-term adverse outcomes and counsel patients on this increased risk. Many patients with AKI who have complete recovery are not followed by a nephrologist, and perhaps they should be."
Disclosures
The study was funded by the National Heart, Lung, and Blood Institute.
Primary Source
ASN Kidney Week
Kendrick J, et al "Acute Kidney Injury is Associated with an Increased Risk of Dementia" ASN Kidney Week 2018;Abstract TH-OR116.