The goal of this observational study is to learn about the prevalence of exocrine pancreatic insufficiency in patients with functional dyspepsia .

. The main questions it aims to answer are: What is the prevalence of exocrine pancreatic insufficiency (EPI) in patients with functional dyspepsia? Wich are the clinical characteristics associated with (EPI) in patients with functional dyspepsia? Patients diagnosed with functional dyspepsia will undergo an evaluation of clinical symptoms and fecal elastase determination. In those with fecal elastase levels below 100 µg/g, an endoscopic ultrasound and other assessments will be performed to define the cause of exocrine pancreatic insufficiency (EPI).

Functional dyspepsia and exocrine pancreatic insufficiency (EPI) represent two gastrointestinal disorders that can occur concomitantly. Functional dyspepsia involves chronic digestive symptoms without identifiable organic causes, while EPI refers to insufficient pancreatic enzyme production for adequate digestion.

Functional dyspepsia is prevalent in the general population, with estimates ranging from 10% to 30% based on various studies. Defined by Rome IV criteria, functional dyspepsia includes epigastric pain, early satiety, or postprandial bloating in the absence of organic conditions. EPI may occur more frequently in individuals with functional dyspepsia. Small studies have identified EPI as a potential mechanism contributing to symptoms. Dyspepsia has been identified as an independent predictor of EPI in research exploring this condition within irritable bowel syndrome.

Recent findings suggest a possible association between EPI and functional dyspepsia. Research by Tahtaci et al. (2018) evaluated EPI in a cohort with functional dyspepsia, revealing that approximately 15% of these patients met criteria for EPI. These findings underscore the importance of evaluating EPI in cases of persistent symptoms unresponsive to conventional treatment. Early identification of EPI may enhance therapeutic management and improve quality of life in this population.

Further studies remain necessary to elucidate the relationship between functional dyspepsia and EPI, establish precise diagnostic criteria, and optimize treatment strategies.

This study adopts a prospective, cross-sectional, and analytical design. A total of 65 patients with functional dyspepsia will undergo assessments including:

• Symptom severity questionnaires addressing depression, anxiety, somatization, and stress.
• Pancreatic Exocrine Insufficiency Questionnaire (PEI-Q).
• Alcohol and tobacco use (anticipated to correlate with higher prevalence of chronic pancreatitis).
• Measurements of weight, height, and abdominal circumference.
• Fecal elastase-1 (Fel-1) testing.
• Serum analysis of pro- and anti-inflammatory cytokines.
• Hydrogen and methane breath testing for small intestinal bacterial overgrowth (SIBO).

EPI will be diagnosed based on fecal elastase-1 concentrations <100 µg/g or values between 100 and 200 µg/g in conjunction with abnormalities in additional pancreatic pathology tests, including serum albumin, vitamin E, vitamin D, vitamin A, folic acid, iron, transferrin, calcium, magnesium, or evidence of malnutrition from anthropometric measurements by a nutritionist. Fecal elastase values ≥200 µg/g will be considered normal.

Patients with fecal elastase values below 200 will undergo additional testing, including:

- Proteinogram, vitamin E, vitamin D, vitamin A, vitamin K, folic acid, B12, calcium, magnesium, zinc, iron profile, and nutritional assessment with anthropometry.

For patients diagnosed with EPI, additional evaluations will include:

- IgG4, alpha-1 antitrypsin, and endoscopic ultrasound.

Based on these parameters, patients will be categorized into EPI and non-EPI groups.

Inclusion Criteria:

• Patients over 18 years of age diagnosed with functional dyspepsia based on Rome IV criteria, who have been excluded for organic, metabolic, and medication-related causes (NSAIDs), and who test negative for H. pylori.

Exclusion Criteria:

• Pregnancy or lactation
• Organic diseases of the digestive tract (celiac disease, inflammatory bowel diseases, neoplasms, positive for H. pylori)
• Uncontrolled systemic diseases (diabetes mellitus, hypo- or hyperthyroidism, cancer, etc.)
• Lack of informed consent
• Severe psychiatric disorders, defined based on the DSM-5

Patients over 18 years of age diagnosed with functional dyspepsia based on Rome IV criteria, who have been excluded for organic, metabolic, and medication-related causes (NSAIDs), and who test negative for H. pylori.

The Rome IV criteria for functional dyspepsia include the presence of one or more of the following symptoms: bothersome postprandial fullness, early satiation, epigastric pain, or epigastric burning, occurring at least once a week in the last three months with symptom onset at least six months prior to diagnosis.

The data sets, including the redacted study protocol, redacted statistical analysis plan, and individual participant data supporting the results reported in this article, will be made available within 3 months from initial request to researchers who provide a methodologically sound proposal. The data will be provided after its de-identification, in compliance with applicable privacy laws, data protection, and requirements for consent and anonymization.