Plasma kidney injury molecule levels linked to kidney failure, lesions
Study results of patients with kidney diseases showed plasma kidney injury molecule-1 was associated with underlying tubulointerstitial and mesangial lesions and progression to kidney failure.
“Collectively, the findings suggest that plasma kidney injury molecule-1 (plasma KIM-1) may serve as a non-invasive tool to assess histopathologic lesions and has prognostic value across a variety of kidney diseases,” Insa M. Schmidt, MD, MPH, assistant professor at Boston University School of Medicine, and colleagues wrote. They added, “Our findings suggest that plasma KIM-1 may be able to provide a non-invasive estimate of more severe acute tubular injury independent of kidney function, which warrants further investigation.”
To determine the association of plasma KIM-1 with kidney disease risk, Schmidt and colleagues conducted two prospective cohort studies. These included 524 patients who were undergoing clinically indicated native kidney biopsy enrolled in the Boston Kidney Biopsy Cohort (BKBC) study and 3,800 patients with common forms of chronic kidney disease enrolled into the Chronic Renal Insufficiency Cohort (CRIC) study. Researchers evaluated patients’ baseline plasma samples, histopathologic lesions and progression to kidney failure.
In the BKBC study, the mean age of patients was 53 years. Patients had an average eGFR of 56 mL/min/1.73 m². The median follow-up was 5 years. The most common primary diagnoses included proliferative glomerulonephritis (29.1%), non-proliferative glomerulopathy (18.3%), advanced glomerulosclerosis (11.3%) and diabetic nephropathy (11.1%). Plasma KIM-1 correlated negatively with eGFR and positively with proteinuria, according to researchers. Plasma KIM-1 levels were significantly higher in patients with more severe lesions and among those with diabetic nephropathy, tubulointerstitial disease, non-proliferative glomerulopathy and proliferative glomerulonephritis.
After follow-up, 124 patients had kidney failure and 85 died. The researchers found a doubling of plasma KIM-1 was associated with a 1.19-fold increased risk of kidney failure.
In the CRIC study, the mean age of patients was 58 years. Patients had an average eGFR of 45 mL/min/1.73 m². According to researchers, those with higher levels of plasma KIM-1 were more likely to be “non-white,” had a greater prevalence of diabetes, cardiovascular disease, higher systolic BP and lower hemoglobin. The median follow-up was 11.5 years.
Plasma KIM-1 had a negative correlation with eGFR and a positive correlation with the urine albumin-creatinine ratio, according to researchers. After follow-up, 1,153 patients had kidney failure and 1,356 died. A doubling of plasma KIM-1 correlated with a 1.10-fold increased risk for kidney failure.
Variability between the two studies limited researchers’ conclusions.
“We found that higher levels of plasma KIM-1 are associated with more severe tubulointerstitial and mesangial lesions and progression to kidney failure in two cohort studies of individuals with kidney diseases,” Schmidt and colleagues wrote. “The strong associations with histopathologic lesions and progression to kidney failure suggest that plasma KIM-1 may potentially serve as a kidney-specific marker to enhance the estimation of the risk of progression to kidney failure across a diverse spectrum of kidney diseases.”
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