C-reactive protein as a non-linear predictor of prolonged length of intensive care unit stay after gastrointestinal cancer surgery

Abstract

BACKGROUND The relationship between C-reactive protein (CRP) levels and prolonged intensive care unit (ICU) length of stay (LoS) has not been well defined. AIM To explore the association between CRP levels at ICU admission and prolonged ICU LoS in gastrointestinal cancer (GC) patients after major surgery. METHODS A retrospective study was performed to quantify serum CRP levels and to establish their association with prolonged ICU LoS (≥ 72 h) in GC patients admitted to the ICU. Univariate and multivariate regression analyses were conducted, and restricted cubic spline curves with four knots (5%, 35%, 65%, 95%) were used to explore non-linearity assumptions. RESULTS A total of 408 patients were enrolled. Among them, 83 (20.3%) patients had an ICU LoS longer than 72 h. CRP levels were independently associated with the risk of prolonged ICU LoS [odds ratio (OR) 1.47, 95% confidence interval (CI) 1.00–2.17]. Restricted cubic spline analysis revealed a non-linear relationship between CRP levels and OR for the prolonged ICU LoS (P = 0.035 for nonlinearity). After the cut-off of 2.6 (log transformed mg/L), the OR for prolonged ICU LoS significantly increased with CRP levels. The adjusted regression coefficient was 0.70 (95%CI 0.31–1.57, P = 0.384) for CRP levels less than 2.6, whereas it was 2.43 (95%CI 1.39–4.24, P = 0.002) for CRP levels higher than 2.6. CONCLUSION Among the GC patients, CRP levels at ICU admission were non-linearly associated with prolonged ICU LoS in survivors. An admission CRP level > 2.6 (log transformed mg/L) was associated with increased risk of prolonged ICU LoS.