Abstract P456: The Association Between Clonal Hematopoiesis Of Indeterminate Potential And Inflammatory Biomarkers Among Chronic Kidney Disease Patients
Authors: Shi Mengyao , Sun Xiao , Bick Alexander , He Jiang , Anderson Amanda H , Hixson James E , Natarajan Pradeep , Kelly Tanika N 
Published: March 2020

Introduction:
Clonal hematopoiesis of indeterminate potential (CHIP) is an age-related disorder associated with increased risk of atherosclerotic cardiovascular disease (ASCVD). Mechanistic studies of CHIP implicate inflammatory pathways underlying this relationship. Although inflammation is a well-established component of chronic kidney disease (CKD), linked to both CKD progression and ASCVD in CKD patients, CHIP has not been investigated in a CKD setting.

Objective:
To estimate the prevalence of CHIP in patients with CKD and to examine the cross-sectional associations between CHIP and biomarkers that were previously related to CKD progression and ASCVD among CKD patients.

Methods:
The current study was conducted among 598 Chronic Renal Insufficiency Cohort (CRIC) study participants with whole-exome sequencing data and baseline measures of fibrinogen, interleukin (IL)-6, serum albumin, and tumor necrosis factor-α. CHIP was detected from sequencing data using MuTect2. CHIP was defined as the presence of a somatic hematologic malignancy-associated mutation with a variant allele frequency (VAF) of at least 2%. CHIP was also categorized ordinally by clone size as no CHIP, small CHIP clone (VAF<10%), and large CHIP clone (VAF ≥10%). Ordinal logistic regression was used to test associations of CHIP with each biomarker in age- and multivariable-adjusted models. Multivariable models adjusted for age, sex, ancestry, body mass index, estimated glomerular filtration rate, systolic blood pressure, low-density lipoprotein cholesterol, fasting plasma glucose, and blood pressure, lipid, and glucose lowering medications.

Results:
CHIP was detected in a total of 28 individuals from the WES study (4.7%). Among those 70 years of age and older, we detected a CHIP prevalence of nearly 16%. As expected, participants with CHIP were older than those without CHIP (mean age: 67 and 58 years, respectively; P<0.0001). Other demographic and clinical variables were similar between groups
.
Age-adjusted models showed strong associations between CHIP and both fibrinogen and IL-6 with odds ratios of 2.49 (95% CI: 1.09, 5.71) and 2.45 (95% CI: 1.05, 5.72), respectively. After multivariable adjustment, only fibrinogen remained associated with CHIP with an odds ratio of 4.70 (95% CI: 1.69, 13.0). Consistent with these findings, there was a strong dose-dependent association between CHIP clone size and fibrinogen in multivariable adjusted analyses (P for linear trend=0.009). Compared to those without CHIP, odds ratios for higher fibrinogen tertile were 3.0 (95% CI: 0.84, 11.3) and 4.7 (95% CI: 1.29, 16.7) among those with small and large CHIP clone sizes, respectively.

Conclusions:
CHIP prevalence was higher among CKD patients in the current study compared to previous estimates from the general population. Furthermore, a strong, dose-dependent association between CHIP and fibrinogen was identified.