Value of neutrophil-lymphocyte ratio in evaluating response to percutaneous catheter drainage in patients with acute pancreatitis

BACKGROUND: Early prediction of response to percutaneous catheter drainage (PCD) of necrotic collections in acute pancreatitis (AP) using simple and objective tests is critical as it may determine patient prognosis. The role of white blood cell (WBC) count and neutrophil-lymphocyte ratio (NLR) has not been assessed as a tool of early prediction of PCD success and is the focus of this study. AIM: To assess the value of WBC and NLR in predicting response to PCD in AP. METHODS: This retrospective study comprised consecutive patients with AP who underwent PCD between June 2018 and December 2019. Severity and fluid collections were classified according to the revised Atlanta classification and organ failure was defined according to the modified Marshall Score. WBC and NLR were monitored 24 h prior PCD (WBC-0/NLR-0) and 24 h (WBC-1/NLR-1), 48 h (WBC-2/NLR-2) and 72 h (WBC-3/NLR-3) after PCD. NLR was calculated by dividing the number of neutrophils by the number of lymphocytes. The association of success of PCD (defined as survival without the need for surgery) with WBC and NLR was assessed. The trend of WBC and NLR was also assessed post PCD. RESULTS: One hundred fifty-five patients [median age 40 ± 13.6 (SD), 64.5% males, 53.5% severe AP] were included in the final analysis. PCD was done for acute necrotic collection in 99 (63.8%) patients and walled-off necrosis in 56 (36.1%) patients. Median pain to PCD interval was 24 ± 69.89 d. PCD was successful in 109 patients (group 1) and 46 patients (group 2) who failed to respond. There was no significant difference in the baseline characteristics between the two groups except the severity of AP and frequency of organ failure. Both WBC and NLR showed an overall decreasing trend. There was a significant difference between WBC-0 and WBC-1 (P = 0.0001). WBC-1 and NLR-1 were significantly different between the two groups (P = 0.048 and 0.003, respectively). The area under the curve of WBC-1 and NLR-1 for predicting the success of PCD was 0.602 and 0.682, respectively. At a cut-off value of 9.87 for NLR-1, the sensitivity and specificity for predicting the success of PCD were calculated to be 75% and 65.4% respectively. CONCLUSION: WBC and NLR can be used as simple tests for predicting response to PCD in patients with acute necrotizing pancreatitis.