Acute pancreatitis is among the most common gastroenterology diagnosis in the United States, and represents a large economic burden to the United States health system. While recent guidelines agree early feeding shortens length of stay, these guidelines fail to provide recommendations on optimal diet to start leaving diet type to clinician discretion. Therefore, the aim is to assess the comparative efficacy of full calorie regular diet (RD) versus clear liquid diet (CLD) on length of hospital stay (LOHS) for mild to moderate acute pancreatitis (AP). The study population will target mild to moderate acute pancreatitis patients who can tolerate eating in a single institution. The primary end point will focus on LOHS, and secondary end points will include Pancreatic Activity Scoring System, side effects and readmission.

Purpose: To assess the comparative efficacy of initial full calorie regular diet (RD) versus clear liquid diet (CLD) on length of hospital stay (LOHS) for mild to moderate acute pancreatitis (AP).

Study Design:

Patients presenting to the Los Angeles County Hospital with mild to moderate acute pancreatitis are eligible and are the focus population of this study. Diagnosis and severity classification will be according to the Revised Atlanta classification and Modified Marshal Score. Patients will require fulfillment of 2 of 3 criteria: amylase or lipase greater than 3 times the upper limit of normal, classic epigastric abdominal pain, or unequivocal imaging consistent with acute pancreatitis.

Patients within the inclusion and exclusion parameters will be randomized to RD vs. CLD within 16 hours of diagnosis of pancreatitis. Randomization will be performed using a random sequence algorithm with concealed allocation. The provision of diet in the emergency department prior to randomization will be recorded but not impact randomization strategy.

Following randomization, the diet of RD vs. CLD will begin as soon as patient expresses an appetite and willingness to eat. The patients will be assessed within 24 hours for hunger and interest in initiating oral feeding which accords with the 2018 recommendations of the American Gastroenterology Association for the management of acute pancreatitis.

The diet algorithm will be randomization to a 1:1 of full regular diet versus clear liquid diet per the Los Angeles County + University of Southern California nutrition department. This nutritional composition is confirmed by the in-house dietician and nutrition department. Regular diet will reflect the U.S. Department of Health and Human Services Dietary guidelines for 2015-202013 and meets recommendations of the International Consensus Guidelines for Nutrition Therapy for Pancreatitis. Fat content is modest in both groups; it is set at 20-35% of caloric intake for regular diet and 15-20% for clear liquid diet. Patients with diabetes mellitus will received modified versions of the regular or clear diet to reflect American Diabetes Association (ADA) requirements. This will be the standard of care composition provided to all patients at Los Angeles County + University of Southern California Medical Center with diabetes deemed by their providers to have a diet modified for diabetes (ADA) diet.

A complete history and physical exam will be taken at time of admission within 24 hours during time of enrollment. Then at 48 hours, 72 hours, and every day until discharge, the patient will have a targeted history including oral tolerance, pain and pain medication requirement, and baseline and changes in Pancreatic Activity Scoring System (PASS). The percent of completed diet per meal will also be recorded. At one week, patients will be contacted for symptom relapse check up by phone and at thirty days, the electronic record will be reviewed to capture possible readmissions. While patients and the study team will be unblinded following discharge, a blinded coordinator will use the length of stay function to capture the primary endpoint which is length of hospitalization.

Pain and pain medications are automatically documented in the Electronic Medical Record(EMR) for monitoring and quantification. A Wong-Baker Pain (FACES) scale is the current validated pain score used by nursing staff. Pain is recorded on a pain scale from 0-10 that matches prior landmark and contemporary studies of acute pancreatitis. Quantification of pain medication by both acetaminophen and morphine equivalents will be recorded in data collection sheets.

If patients have oral intolerance or ileus, their diet will be managed at the discretion of their treating physicians and recorded by the study team. It will be recommended that diets remain consistent and titrated in quantity per physician and patient preference; however, if there is a physician preference to change to a different diet type this will be recorded and the patient will be included in the intention to treat analysis

For severe pancreatitis that develops following enrollment, nutritional management (whether nasal jejunal tube or total parenteral nutrition) will be managed per the primary team and patients will similarly be included in the intention to treat analysis.

Gallstone pancreatitis will be diagnosed by findings of elevated or fluctuating liver enzyme tests and biliary imaging abnormalities including cholelithiasis or ductal dilation. For patients with gallstone pancreatitis who will undergo same admission cholecystectomy, patients will have diet prescribed per assigned randomization but will be made nothing by mouth (NPO) at the discretion of the surgical team in anticipation of the operation. Integration of surgery into the hospitalization may impact length of stay. Therefore, randomization will be stratified by presence of gallstone versus non-gallstone pancreatitis.

Additionally, the study protocol will not impact other strategies/treatments to manage pancreatitis. For example, alcohol counseling will be provided to those whose pancreatitis is related to heavy alcohol use regardless of randomization or the study.

Inclusion Criteria:

1. >18 years of age
2. Presentation with acute pancreatitis as defined by two of three criterion per the Revised Atlanta Criteria guidelines: (a) Amylase or lipase > 3x the upper limit of normal, b) Classical abdominal pain, c) Ultrasound or computed tomography of unequivocal pancreatitis. Such radiographic findings include swelling, edema, or heterogeneity of the gland or peripancreatic fluid or stranding

Exclusion Criteria:

1. Pregnant or breastfeeding women
2. Incarcerated patients
3. Patients < 18 years of age
4. Patient unable or unwilling to give informed consent
5. Patients transferred from another hospital
6. The possibility of poor oral intake for reasons other than acute pancreatitis (e.g. intubation, failure to pass an indicated swallow study for aspiration risk, anorexia secondary to active malignancy, etc)
7. Surgical intervention for infected pancreatic necrosis or pancreatic hemorrhage
8. Chronic pancreatitis based on radiographic evidence
9. Severe pancreatitis based on Revised Atlanta Criteria. Under Revised Atlanta Criteria, patients will be excluded if they have a composite Modified Marshall >2
10. Etiologies of hypertriglyceridemia, trauma and autoimmune pancreatitis will be excluded