Assessment of the Effects of Plasmapheresis on Patients with Hypertriglyceridemia-induced Acute Pancreatitis

Abstract Objectives: Plasmapheresis has been repetitively reported as an effective treatment in hypertriglyceridemiainduced acute pancreatitis (HTG-AP). However, due to heterogeneity in presenting severity, different definition of clinical end-points and lack of well-matched control group, a definitive role of plasmapheresis is yet to be determined. Methods: We reviewed a cohort of 142 unique patients of HTG-AP, in which 15 cases were treated with plasmapheresis. We compared the epidemiologic characteristics, presenting clinical severity and various clinical end-points between plasmapheresis group and non-plasmapheresis group directly and after successful propensity score match. The clinical trajectory of plasmapheresis group and post-match nonplasmapheresis group were plotted and compared. Results: Patients who underwent plasmapheresis had higher triglyceride levels on admission, and had a trend toward more severe pancreatitis. The unmatched cohort revealed that plasmapheresis group had longer hospital stay, required more intravenous insulin, and had longer duration of nil per os. However post-match comparison revealed that plasmapheresis had no effect on clinical outcomes. Despite the successful match of epidemiologic characteristics and presenting clinical severity, plasmapheresis group was responding slower than post-match nonplasmapheresis group, which suggests the existence of unmeasured confounding factors and possibility of obscured benefit given the similarities in various end-points. Conclusions: Although plasmapheresis had no apparent benefit or harm, there likely was residual confounding based on the different clinical trajectories between the plasmapheresis and non-plasmapheresis groups. Randomized controlled trial, or a larger multicentre observational study taking into consideration the clinical trajectory is needed to further evaluate the role of plasmapheresis in HTG-AP.