C-reactive protein and insulin-like growth factor-1 in differential diagnosis of ascites.

Background And Aim: Insulin-like growth factor-1 (IGF-1) and C-reactive protein (CRP) are produced mainly by the liver; the output of these markers in response to inflammatory processes may be affected in patients with hepatic dysfunction. This may explain the differences in IGF-1 and CRP values in patients with non-portal and portal hypertension ascites. We aimed to evaluate serum and ascitic fluid IGF-1 and CRP as diagnostic markers in the differential diagnosis of benign and malignant ascites.

Methods: In this prospective study, 398 consecutive patients with ascites were included. Serum and ascitic fluid levels of IGF-1 and CRP were measured using an enzyme-linked immunosorbent assay.

Results: Patients were divided into group 1, due to benign ascites (n = 324), and group 2, due to malignant ascites (n = 74). Serum and ascitic IGF-1 were significantly increased in malignant ascites than benign ascites group [305 ± 65.7 ng/mL vs 95 ± 53.8 ng/mL; P < 0.001 and 288 ± 54.7 ng/mL vs 83.2 ± 36.7 ng/mL; P < 0.001], respectively. Serum and ascitic CRP were significantly higher in malignant ascites than benign ascites patients [12.8 ± 6.3 mg/mL vs 6.1 ± 4.9 mg/mL; P < 0.001 and 5.1 ± 2.2 mg/mL vs 1.6 ± 1.3 mg/mL; P < 0.001], respectively. At a cutoff value of 309.4 ng/mL and 7.8 mg/mL, serum IGF-1 and CRP had (95.1%, 81%) sensitivity and (88.6%, 75.5%) specificity for detecting malignant ascites [area under the curve: 0.932, 0.845], respectively. At a cutoff value of 291.6 ng/mL and 2.6 mg/mL, ascitic IGF-1 and CRP had (94.6%, 84%) sensitivity and (83.2%, 80.3%) specificity for detecting malignant ascites (area under the curve: 0.911, 0.893) correspondingly.

Conclusion: Elevated serum and ascitic fluid IGF-1 and CRP levels were associated with malignant ascites.