Abstract
BACKGROUND: Acute kidney injury (AKI), a rapid decrease in kidney function, is associated with increased risk of adverse outcomes including development and progression of CKD. Kidney fibrosis is one of the pathological processes central to this AKI-to-CKD transition. Here we investigate the association of biomarkers of collagen type III turnover with adverse outcome following AKI. METHODS: We measured three biomarkers reflecting collagen type III (PRO-C3) formation and degradation (C3M and C3C) in plasma samples collected 1 year after an episode of AKI in 800 patients (392 patients with AKI and 408 non-AKI controls) from the prospective AKI Risk in Derby (ARID) study. Patients were followed until 3 years after the episode of AKI and the following outcomes were assessed: kidney disease progression, mortality, heart failure, cardiovascular events, and hospital readmission. RESULTS: PRO-C3 levels were elevated in the AKI group compared with the controls (P < .001), whereas C3M and C3C levels were not different between groups. In multivariate models including common risk factors, PRO-C3 was prognostic for kidney disease progression and mortality in the AKI group and for heart failure in the control group. C3M and C3C were not prognostic for any of the investigated outcomes. CONCLUSIONS: Circulating PRO-C3, a biomarker of fibroblast activity, was prognostic for kidney disease progression and mortality when measured 1 year after an episode of AKI. Biomarkers of fibroblast activity may help patient stratification after an episode of AKI by identifying patients at higher risk of kidney disease progression.