Background: Despite recent advances of diagnosis and treatment modalities, mortality rate in severe acute pancreatitis is still high. Especially in acute necrotizing pancreatitis (ANP), infectious complications (infected pancreatic necrosis and sepsis) in the late phase are contributors to high mortality. As infected pancreatic necrosis is an indication for surgical treatment (necrosectomy), it is very important to predict infection during the clinical course. Because severity of pancreatitis and immune status of host are two key factors for development of infection, ratio of the balance may be useful as an index for predicting infection. This investigation aimed to propose a simple index for predicting infection in ANP.
Methods: First, as a parameter for severity of pancreatitis, predictable factor for infection was surveyed from data on admission of 75 patients with ANP. Because LDH was the most useful factor, change of LDH after admission and utility of LDH for predicting infection were investigated. Next, as a parameter for the immune status of host, change of lymphocyte count and utility of lymphocyte count for predicting infection were investigated. Then, an index (LDH to lymphocyte ratio) for predicting infection was calculated, and its utility was investigated. Utility for predicting mortality was also evaluated.
Results: LDH was the most useful factor for predicting infection on admission. Utility of LDH for predicting infection was superior to Ranson score and APACHE II score. LDH was significantly higher in infection group on Day 0, 3, and 7 after admission. Among the LDH values (Day 0, 3, 7, 14, and maximum during 14 days), maximum LDH value during 14 days after admission (LDH-max) was most useful for predicting infection. Lymphocyte count was significantly lower in infection group on Day 7 and 14 after admission. Among the lymphocyte counts (Day 0, 3, 7, 14, and minimum during 14 days), lymphocyte count on Day 14 (Lymph-14d) was most useful for predicting infection. LDH-max to Lymph-14d ratio (LDH-max/Lymph-14d) in infection group (4.5 ± 1.0) was significantly higher than that in non-infection group (0.7 ± 0.1). In patients whose ratio was < 1.0, 1.0-2.5, and > 2.5, incidence of infection was 0%, 53%, and 100%, respectively. Moreover, LDH-max/Lymph-14d in non-survivor group (4.9 ± 1.1) was significantly higher than that in survivor group (0.8 ± 0.1). In patients whose ratio was < 1.0, 1.0-2.5, and > 2.5, mortality rate was 4%, 32%, and 100%, respectively.
Conclusion: LDH-max/Lymph-14d is a simple and useful index for predicting infection and mortality in ANP.