Decreased kidney function places elderly individuals at higher risk of infection-related hospitalization, according to a study.
The study, which included 5,142 community-dwelling individuals aged 65 and older who participated in the Cardiovascular Health Study (CHS), found that the risk increases with declining estimated glomerular filtration rate (eGFR).
Compared with individuals with an eGFR of 90 mL/min/1.73 m2 or higher, those with an eGFR of 60-89, 45-59, and 15-44 are at 16%, 37%, and 64% greater risk, respectively, of infection-related hospitalization, researchers reported online in the American Journal of Kidney Diseases. Each 10 mL/min/1.73 m2 decrease in eGFR was associated with an 8% increased risk.
“These findings highlight that even moderate degrees of decreased kidney function are associated with clinically significant higher risks of serious infection in older individuals,” the authors, led by Lorien S. Dalrymple, MD, MPH, of the University of California at Davis, concluded.
During a median follow-up of 11.5 years, 20% of the CHS participants had one infection-related hospitalization and 10% had two or more infection-related hospitalizations.
The association between kidney function and infection-related hospitalization may be due to increased susceptibility to infection, increased severity of infection, or both, in older patients with chronic kidney disease, according to the investigators.
They pointed out that altered immune cell function is a known clinical complication of late-stage kidney disease as indicated by markedly high rates of infection and infection-related deaths in persons with end-stage renal disease on dialysis. Few studies have looked at whether less severe renal impairment is associated with infection risk, they stated.
“Kidney disease is a continuum, and alterations in immune cellular function may develop well before end-stage renal disease, similar to other metabolic abnormalities associated with kidney disease,” the researchers noted.
A major strength of the study, the investigators observed, was the use of cystatin C rather than serum creatinine to estimate kidney function. This allowed them to examine more directly the association between kidney function and infection in older adults, as older populations may have low serum creatinine levels because of low muscle mass or malnutrition.