Association between C-reactive protein and all-cause mortality among critically ill patients with acute kidney injury

To explore the relationship between C-reactive protein (CRP) and mortality in critically ill patients with acute kidney injury (AKI).

A total of 580 patients diagnosed with AKI within 48 hours of ICU admission between September 2017 and August 2019 were enrolled. Patients were followed for all-cause mortality in-hospital and then up to 2 years after discharge. We performed two multivariate regression analysis to assess the association between CRP and mortality, and conducted stratified analysis to assess whether the effect of the CRP differed across subgroups.

According to initial CRP quartiles, patients were divided into 4 groups (quartile 1, CRP ≤ 2.87 mg/L; quartile 2, CRP: 2.87 - 25.95 mg/L; quartile 3, CRP: 25.95 - 111.51 mg/L; quartile 4, CRP > 111.51 mg/L). Patients with high CRP levels have higher APACHE-II score, longer length of stay in the ICU, and higher mortality. In multivariate regression analysis, high CRP was associated with the increased risk of in-hospital mortality after adjusting for age, gender, surgical grade, heart rate, serum potassium, serum chloride, coronary heart disease, and atherosclerotic cerebral infarction (quartile 4 vs. quartile 1, OR: 3.810, 95% CI: 2.081 - 6.973). For 2-year mortality, the increased trend was still significant with the OR (95% CI) of the quartile 4 group of 5.117 (2.678 - 9.780) after adjusting for confounders. Subgroup analyses detected in each group showed that the in-hospital and 2-year risk of mortality increased with higher CRP levels.

Higher CRP level was associated with the increased risk of mortality in critically ill patients with AKI.