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Advanced Neurology eGFR and serum neurofilament light chain
neurofilament light chain (sNfL). This protein, known as equation . The CKD-EPI equation is a widely employed
[12]
sNfL, is released into the bloodstream when nerve cells formula that incorporates the serum creatinine (Scr) level,
sustain damage, rendering it a valuable tool for detecting age, sex, and race of the patient. The equation is represented
and monitoring neurological disorders . as follows:
[4]
In a recent study, sNfL was found to be linked with Scr α Scr −1.209
kidney function , suggesting its potential utility as a marker eGFR = 141 × ,1 ×min max ,1
[5]
for assessing kidney health. As widely acknowledged, one κ κ
approach to evaluating kidney function is through the × Age ×0.993 1.018 × if female 1.159 if black (I)
estimated glomerular filtration rate (eGFR) , a measure of
[6]
the kidneys’ blood-filtering efficiency. eGFR is calculated In Equation I, κ is a constant set at 0.7 for females and
by assessing the concentration of creatinine in the blood, 0.9 for males, while α, another constant, is defined as
with a decrease in eGFR indicating a decline in kidney −0.329 for females and −0.411 for males. The equation uses
function . A recent clinical study revealed that sNfL levels “min” to represent the minimum of Scr/κ or 1, and “max”
[7]
increased with age in elderly individuals over 6 5years old, to indicate the maximum of Scr/κ or 1.
and a negative correlation was observed between sNfL 2.3. Measurement of sNfL
and eGFR . The previous studies have regarded eGFR
[8]
as a confounding factor in investigating the relationship Serum samples from participants in the NHANES
between sNfL and neurodegenerative diseases, including 2013–2014 cohort, aged 20 – 75 years, were used to perform
multiple sclerosis [9,10] . Nevertheless, there has been limited sNfL immunoassays. The immunoassay was conducted
research examining the link between eGFR and sNfL in using the Attelica platform from Siemens Healthineers,
the general population. Given this gap, our study aimed employing acridinium ester (AE) chemiluminescence
to explore the relationship between eGFR and sNfL using and paramagnetic particles. The assay process involved
data from the NHANES database. incubating the serum sample with AE-labeled antibodies
specifically designed to bind to the sNfL antigen.
2. Method Subsequently, paramagnetic particles coated with capture
antibodies were introduced, resulting in the formation
2.1. Data and population
of complexes comprising the sNFL antigen bound to
NHANES, an acronym for the National Health and AE-labeled antibodies and paramagnetic particles.
Nutrition Examination Survey, is a crucial survey led Following the removal of unbound AE-labeled antibodies,
by the Centers for Disease Control and Prevention chemiluminescence was initiated by adjusting the pH, and
(CDC). Its primary objective is to assess the health and the resulting light emission was quantified.
nutritional status of both adults and children throughout
the United States. NHANES employs a comprehensive 2.4. Assessment of covariates
and nationally representative survey methodology, using In this study, we adjusted for potential confounding
a complex sampling design to ensure that the collected factors by including age, sex, education, marital status,
data accurately reflects the entire U.S. population. The and self-reported information on smoking, drinking,
program has maintained continuity since 1999, with new heart failure (HF), myocardial infarction (MI), and stroke.
data released in 2-year cycles. For our study, we utilized Chronic kidney disease (CKD) is characterized by either
physical examination and self-reported data from the kidney damage or reduced kidney function, as indicated
2013–2014 cycle, as sNfL information was exclusively by an eGFR <60 ml/min/1.73 m or a urine albumin-
2
recorded during this period. Participants with missing creatinine ratio of 30 or higher . Metabolic syndrome
[13]
eGFR and sNfL information were excluded from the study, is diagnosed when a person has three or more of the
resulting in a final study cohort of 2071 participants (age following risk factors: High waist circumference, elevated
≥20). All NHANES protocols have received approval from triglycerides, reduced high-density lipoprotein (HDL)
the National Center for Health Statistics Research Ethics cholesterol, high blood pressure, and high fasting glucose
Review Board. All participants provided written informed levels . Hyperlipidemia is diagnosed if at least one of
[14]
consent, and the researcher had access to the database the following criteria is met : A total cholesterol level
[15]
without the need for additional application . of 200 mg/dL or higher, a triglyceride level of 150 mg/dL
[11]
or higher, an HDL cholesterol level of 40 mg/dL or lower
2.2. Calculation of eGFR
in males and 50 mg/dL or lower in females, or a low-
The estimated glomerular filtration rate, a measure density lipoprotein (LDL) cholesterol level of 130 mg/dL
of kidney function, is calculated using the CKD-EPI or higher. Alternatively, individuals using cholesterol-
Volume 2 Issue 3 (2023) 2 https://doi.org/10.36922/an.1394
