Introduction: Soluble urokinase-type plasminogen activator receptor (suPAR) strongly predicts outcomes and incident chronic kidney disease (CKD) in patients with cardiovascular disease (CVD). Whether the association between suPAR and CKD is a reflection of its overall association with chronic inflammation and poor CVD outcomes is unclear. We examined whether CVD biomarkers, including high-sensitivity C-reactive protein (hs-CRP), fibrin-degradation products (FDPs), heat-shock protein 70 (HSP-70), and high-sensitivity troponin I (hs-TnI) were associated with a decline in kidney function in the Emory Cardiovascular Biobank cohort, in which suPAR levels were shown to be predictive of both incident CKD and CVD outcomes.
Methods: We measured suPAR, hs-CRP, HSP-70, FDP, and hs-TnI plasma levels in 3282 adults (mean age 63 years, 64% male, 75% estimated glomerular filtration rate [eGFR] >60 ml/min per 1.73 m2). Glomerular filtration rate was estimated using Chronic Kidney Disease-Epidemiology Collaboration (eGFR) at enrollment (n = 3282) and follow-up (n = 2672; median 3.5 years). Urine protein by dipstick at baseline was available for 1335 subjects.
Results: There was a weak correlation among biomarkers (r range: 0.17-0.28). hs-CRP, FDPs, hs-TnI, and suPAR were independently associated with baseline eGFR and proteinuria. The median yearly decline in eGFR was -0.6 ml/min per 1.73 m2. hs-CRP (β: -0.04; P = 0.46), FDPs (β: -0.13; P = 0.08), HSP-70 (β: 0.05; P = 0.84), or hs-TnI (β: -0.01; P = 0.76) were associated with eGFR decline. suPAR remained predictive of eGFR decline even after adjusting for all biomarkers.
Discussion: hs-CRP, FDP, HSP-70, and hs-TnI were not associated with eGFR decline. The specific association of suPAR with eGFR decline supported its involvement in pathways specific to the pathogenesis of kidney disease.
Keywords: CKD; CRP; FDP; HSP-70; creatinine; eGFR; proteinuria; troponin; urokinase.