Which patients with palliative malignant biliary obstruction will benefit most from biliary drainage: development, validation of a prognostic score

Background: Biliary drainage is performed in palliative malignant biliary obstruction (MBO) to improve patients’ quality of life and enable chemotherapy. This study aimed to create and validate a prognostic score after biliary drainage in patients with palliative MBO. Methods: multicenter retrospective study, patients undergoing endoscopic or percutaneous drainage for palliative MBO were included. Probability factors associated with 30-day mortality were evaluated by univariable and multivariable logistic regression in the derivation cohort, a prognostic score was built and evaluated in an independent validation cohort. Results: derivation cohort included 262 patients, 55% male, 61% of pancreatic adenocarcinoma, mean age 72. Probability factors associated with 30-day mortality identified in the derivation cohort were WHO performance status of 3-4 (OR 7.7 [2.57-25.0] ; +3 points), liver metastases (OR 2.7 [1.06-6.98] ; +1 point), other metastases (OR 3.85 [1.57-9.97] ; +2 points), leukocytes >12G/l (OR 2.4 [0.94-6.08]; +1 point), total bilirubin >10.8mg/dl (OR 4.3 [1.45-15.20] ; +2 points) and creatininemia >5.0mg/dl (OR 7.3 [2.89-19.86]; +3 points). The multivariable model showed good discrimination, with an AUROC of 0.86 (95% CI, 0.80-0.93). The prognostic score was used to define two groups of patients, with a low (0-4 points) or high-probability (>4 points) of 30-day mortality (3% and 32%, respectively). The AUROC in the validation cohort (192 patients) was 0.72, with 30-day mortality of 7% in the low- probability group and 22% in the high- probability group (p=0.02). Conclusions: This score could be used in routine clinical practice to identify patients who have better survival outcomes after biliary drainage in palliative MBO.