Establishment and Clinical Application of Pancreatic Endocrine and Exocrine Function Tests

The goal of this observational study is to improve the epidemiological data of pancreatic exocrine insufficiency in China, determine the FE-1 cut-off value for the classification of PEI, and explore the characteristic differences between T3cDM and type 2 diabetes mellitus in clinical symptoms and laboratory indicators.

Pancreatic exocrine insufficiency (PEI) refers to the reduction in the synthesis and secretion of pancreatic enzymes caused by various reasons, which leads to malabsorption and even nutritional deficiencies. The main causes of PEI include chronic pancreatitis (CP), acute pancreatitis, pancreatic cancer, pancreatectomy, enterectomy, diabetes mellitus and cystic fibrosis. Due to its numerous etiologies, the current prevalence of PEI is uncertain and very varied. The prevalence of PEI in the Chinese population is still lacking. Diagnosis of PEI in clinical practice is hindered by the lack of accurate tests, and it usually requires the combination of symptoms, nutritional markers and a noninvasive pancreatic function test in the appropriate clinical context. At present, the fecal elastase-1 (FE-1) test is the most widely applied non-invasive approach in routine clinical practice. First, the study plans to record the baseline data of participants and perform the FE-1 test in specific elderly population and community population, in order to improve the epidemiology of PEI in China. Second, the study will perform the FE-1 test in 100 CP patients, in order to determine the FE-1 cut-off value for the classification of PEI (mild-moderate and severe), using the coefficient of fat absorption as the "gold standard". Third, people with CP often have diabetes mellitus which is described as type 3c diabetes mellitus (T3cDM). However, there are no recognized diagnostic criteria for T3cDM. Studies have shown that close to 50% of T3cDM cases are misclassified, most of which are diagnosed as type 2 diabetes mellitus (T2DM). According to certain research, the early stages of T3cDM are characterized by insufficient insulin and C-peptide secretion. The study will provide laboratory testing to 300 patients with T3cDM and T2DM in order to compare the differences and create T3cDM diagnostic criteria.