S2 Recurrent Episode of Acute Pancreatitis in Patients With Idiopathic Acute Pancreatitis and Fatty Pancreas on Endoscopic Ultrasound

Introduction: Idiopathic acute pancreatitis (IAP) is diagnosed after a negative evaluation. It remains unclear if fatty pancreas is a cause of acute pancreatitis (AP) or a risk factor for recurrent AP. We aimed to determine if fatty pancreas was associated with a recurrent episode of AP in patients with IAP. Methods: Patients with IAP were identified across three academic centers. Patients were included if they underwent an endoscopic ultrasound (EUS) at one of our centers. Presumed IAP prior to EUS was confirmed through retrospective review of clinical data. Patients who had an etiology discovered on EUS were excluded, leaving a cohort of “true” IAP. Presence of fatty pancreas on EUS was noted. Recurrent episode of AP, emergence of diabetes, chronic pancreatitis, and follow up cholecystectomy were recorded. Univariable analysis was performed using Wilcoxon Rank Sum or Fisher Exact tests. A Cox Proportional Hazard Regression Analysis was performed for a recurrent episode of AP. Results: 105 patients with “true” IAP were identified. Fatty pancreas was noted in 31 patients on EUS. Older age, male gender, white race, higher BMI, obesity, presence of fatty liver, and type 2 diabetes mellitus were associated with fatty pancreas on univariable analysis (Table 1). Five patients had no follow up data after the EUS. Median time of follow up was 687 days (IQR 464–1026 days). During the follow up period, 16 patients had a recurrent episode of AP (16/100, 16%; median time to recurrence 216 days, IQR 76–420 days), 8 were diagnosed with new diabetes (8/48, 16.7%), 5 with chronic pancreatitis (5/38, 13.2%), and 10 underwent cholecystectomy (10/56, 17.9%). On unadjusted Cox regression analysis, being evaluated as a referral (P = 0.0417), a history of necrotizing pancreatitis (P = 0.0073), number of attacks within the preceding year before EUS (P = 0.0012), and total bilirubin at the most recent episode of AP (P = 0.0217) were associated with a recurrent episode of AP (Figure 1). Neither the presence of fatty pancreas nor fatty liver were significant. Conclusion: The incidence of a recurrent episode of AP was 16% over approximately 2 years in patients with IAP. The presence of fatty pancreas was not associated with a recurrent episode. Further studies on fatty pancreas in IAP are recommended. Table 1. - Patient characteristics Baseline CharacteristicsMedian (IQR) or Fraction (%) Unadjusted Univariable AnalysisMedian (IQR) or Fraction (%) Unadjusted Cox RegressionFor Recurrent Episode AP All PatientsN=105 No fatty pancreasN=74 Fatty pancreasN=31 p-value HR (95% CI) p-value Age at EUS, per 5 years 53.8 (40.4-64.3) 47.6 (37.9-60.4) 63.7 (53.9-68.2) < 0.0011 0.92 (0.79-1.08) 0.3203 Male gender 45 (42.9%) 27 (36.5%) 18 (58.1%) 0.0532 1.56 (0.57-4.30) 0.3901 BMI, per 5 kg/m2 28.2 (24.2-33.7) 26.6 (22.9-29.5) 33.7 (30.4-38.8) < 0.0011 1.00 (0.73-1.38) 0.9769 Obesity 43 (41.0%) 17 (23.0%) 26 (83.9%) < 0.0012 1.14 (0.41-3.15) 0.7984 White Race 96 (91.4%) 65 (87.8%) 31 (100.0%) 0.0552 0.55 (0.12-2.46) 0.4361 Hispanic Ethnicity 3 (2.9%) 2 (2.7%) 1 (3.2%) 1.0002 2.46 (0.32-18.82) 0.3859 Never Smoker 63 (60.0%) 47 (63.5%) 16 (51.6%) 0.2812 0.45 (0.16-1.27) 0.1324 Diabetes Mellitus, type 2 35 (33.3%) 20 (27.0%) 15 (48.4%) 0.0432 1.23 (0.44-3.47) 0.6890 Cholecystectomy 47 (44.8%) 34 (45.9%) 13 (41.9%) 0.8302 0.81 (0.29-2.28) 0.6947 Fatty Liver 47 (44.8%) 24 (32.4%) 23 (74.2%) < 0.0012 0.69 (0.25-1.94) 0.4848 Evaluated as referral 74 (70.5%) 54 (73.0%) 20 (64.3%) 0.4822 0.35 (0.13-0.96) 0.0417 Necrotizing pancreatitis 11 (10.5%) 8 (10.8%) 3 (9.7%) 1.0002 4.36 (1.49-12.78) 0.0073 Single episode of AP 43 (41.0%) 30 (40.5%) 13 (41.9%) 1.0002 0.92 (0.33-2.58) 0.8712 Total attacks of AP 2 (1-3) 2 (1-3) 2 (1-3) 0.9331 1.16 (0.96-1.40) 0.1299 Attacks within year of EUS, per 1 attack 1 (1-2) 1 (1-2) 1 (1-2) 0.3491 1.85 (1.28-2.70) 0.0012 Fatty pancreas on EUS 31 (29.5%) NA NA NA 0.74 (0.24-2.34) 0.6618 At most recent episode of AP Lipase, per 500 U/L 920 (275-2530) 1000 (413-2500) 359 (190-3000) 0.1521 1.01 (0.97-1.06) 0.5787 Total bilirubin, per 1 mg/dL 0.4 (0.3-0.6) 0.4 (0.3-0.6) 0.5 (0.4-0.6) 0.5951 5.52 (1.28-23.71) 0.0217 Direct bilirubin, per 1 mg/dL 0.2 (0.2-0.2) 0.2 (0.2-0.2) 0.2 (0.2-0.2) 0.070 23.55 (0.3-1835.4) 0.1552 ALT, per 10 U/L 24 (17-35) 21 (16-33) 30 (24-39) 0.0091 0.96 (0.79-1.17) 0.7021 Calcium, per 1 mg/dL 9.4 (9.1-9.6) 9.4 (9.1-9.7) 9.3 (9.1-9.5) 0.2381 0.25 (0.06-1.08) 0.0626 Triglycerides, per 50 mg/dL 103 (75-173) 103 (74-158) 104 (85-177) 0.6041 1.07 (0.83-1.36) 0.6142 IgG4 level, per 10 mg/dL 23.9 (11.1-41.0) 25.2 (11.9-40.1) 22.5 (11.3-39.7) 0.8871 0.96 (0.76-1.21) 0.7190 CA 19-9, per 10 U/mL 8.5 (5-13) 8.5 (5.8-13.0) 7.5 (5-15) 0.7121 0.87 (0.49-1.53) 0.6281 IQR, interquartile range; AP, acute pancreatitis; HR, hazard ratio; 95% CI, 95% confidence interval; EUS, endoscopic ultrasound; BMI, body mass index; NA, not applicable; ALT, alanine transaminase; IgG4, immunoglobulin G type 4; CA 19-9, carbohydrate antigen 19-9 Reference ranges: Lipase 13 – 60 U/L, Total Bilirubin ≤ 1.2 mg/dL, Direct Bilirubin 0.0 – 0.3 mg/dL, ALT 7 – 55 U/L, Triglycerides < 150 mg/dL, Calcium 8.8 – 10.2 mg/dL, CA 19-9 < 35 U/mL, IgG4 2.4 – 121.0 mg/dL 1. Wilcoxon Rank Sum Test 2. Fisher Exact Test Figure 1.: Kaplan-Meier Estimates for Time to Recurrent Episode of Acute Pancreatitis. A) Entire Cohort of Patients with IAP. B) By History of Necrotizing Pancreatitis. C) By Presence of Fatty Pancreas on EUS. Legend B: Blue = History of Necrotizing Pancreatitis, Red = No History of Necrotizing Pancreatitis. Legend C: Blue = Fatty Pancreas on EUS, Red = Non-Fatty Pancreas on EUS.