Clinical significance of single and persistent elevation of serum high-sensitivity C-reactive protein levels for prediction of kidney outcomes in patients with impaired fasting glucose or diabetes mellitus.

BACKGROUND The association between high-sensitivity C-reactive protein (hs-CRP) and chronic kidney disease remains controversial and long-term longitudinal studies are limited. We aim to investigate the impact of single and persistent elevation of hs-CRP on kidney outcomes. METHODS Our study was based on a subgroup of patients with hyperglycemia from the Kailuan cohort. Patients were divided into three groups according to two consecutive hs-CRP levels: (1) no elevation (twice hs-CRP < 3 mg/L); (2) single elevation (once hs-CRP ≥ 3 mg/L); (3) persistent elevation (twice hs-CRP ≥ 3 mg/L). Kidney outcomes include kidney function decline (glomerular filtration rate [GFR] decline ≥ 30% within two years or doubling of serum c reatinine or development of end stage kidney disease [ESKD]), development and progression of proteinuria. RESULTS Regarding the outcomes of kidney function decline, development and progression of proteinuria, we included 18,665, 11,754 and 1710 patients into analyses, respectively. After 5 years of follow-up, the number of incident cases of kidney function decline, development and progression of proteinuria were 1891, 1337 and 171, respectively. Compared to patients with no elevation of hs-CRP levels, those with persistent but not single elevation of hs-CRP were at higher risk of kidney function decline (hazard ratio [HR] 1.42, 95% confidence interval [CI] 1.23-1.64) and development of proteinuria (1.49, 1.26-1.76), but not progression of proteinuria. The results were consistent with propensity score analysis. CONCLUSION Persistent but not single elevation of hs-CRP was independently associated with increased risk of kidney function decline, and development of proteinuria but not progression in patients with impaired fasting glucose or diabetes.