Low High‐Sensitivity C‐Reactive Protein Level in Korean Patients With Chronic Kidney Disease and Its Predictive Significance for Cardiovascular Events, Mortality, and Adverse Kidney Outcomes: Results From KNOW‐CKD

BACKGROUND: Inflammation levels are lower in East Asians than in Western people. We studied the association between high‐sensitivity hs‐CRP (C‐reactive protein) and adverse outcomes in Korean patients with chronic kidney disease. METHODS AND RESULTS: We included 2018 participants from the KNOW‐CKD (Korean Cohort Study for Outcome in Patients With Chronic Kidney Disease) between April 2011 and February 2016. The primary outcome was a composite of extended major cardiovascular events (eMACE) or all‐cause mortality. The secondary end points were separate outcomes of eMACE, all‐cause death, and adverse kidney outcome. We also evaluated predictive ability of hs‐CRP for the primary outcome. The median hs‐CRP level was 0.60 mg/L. During the mean follow‐up of 3.9 years, there were 125 (6.2%) eMACEs and 80 (4.0%) deaths. In multivariable Cox analysis after adjustment of confounders, there was a graded association of hs‐CRP with the primary outcome. The hazard ratios for hs‐CRPs of 1.0 to 2.99 and ≥3.0 mg/L were 1.33 (95% CI, 0.87–2.03) and 2.08 (95% CI, 1.30–3.33) compared with the hs‐CRP of <1.0 mg/L. In secondary outcomes, this association was consistent for eMACE and all‐cause death; however, hs‐CRP was not associated with adverse kidney outcomes. Finally, prediction models failed to show improvement of predictive performance of hs‐CRP compared with conventional factors. CONCLUSIONS: In Korean patients with chronic kidney disease, the hs‐CRP level was low and significantly associated with higher risks of eMACEs and mortality. However, hs‐CRP did not associate with adverse kidney outcome, and the predictive performance of hs‐CRP was not strong. REGISTRATION: URL: http://www.clinicaltrials.gov; Unique identifier: NCT01630486.