The role of cystic fibrosis associated diabetes mellitus in the natural course of cystic fibrosis increases, as the life expectancy of patients increases. Consequently, its prevalence and manifestations of adverse effects are growing. The incidence of MASD is 5% in patients with MB, but varies between 15-22% in patients over the age of 16. The influence of the prediabetic state and diabetes mellitus in patients with cystic fibrosis: • accelerates the decline in lung function; • increases the frequency of exacerbations of pulmonary disease; • causes premature death. Pathogenesis of cystic fibrosis-associated diabetes mellitus Almost all patients with cystic fibrosis-associated diabetes mellitus have pancreatic insufficiency. The cause of cystic fibrosis associated diabetes mellitus is probably a gradual physical destruction (3 cells, causing a decrease in insulin levels. The first biochemical manifestation is a slowdown in insulin secretion. Postprandial delay in insulin secretion explains the violation of the glucose tolerance test performed by mouth (PTG), which is one of the main methods for diagnosing MASD.The manifestations of the prediabetic state are an increase in the frequency of exacerbations of a pulmonary disease, an accelerated decrease in the functions of mild and severe weight loss. Sometimes, but not often, polydipsia and polyuria are present. Diagnosis and classification of cystic fibrosis-associated diabetes mellitus There are three main indicators of cystic fibrosis associated diabetes mellitus: • an increase in plasma fasting glucose concentration; • PTTG results corresponding to diabetes mellitus; • an increase in plasma glucose concentration during its continuous monitoring. Cystic fibrosis associated diabetes mellitus is divided into 3 categories, characterized by s as different stages: • category 1 – violation OGTT, but a normal fasting plasma glucose concentration at random and measuring (Biochemistry diabetes); • Category 2 – increased randomly measured plasma glucose concentration within the range of diabetes mellitus, but its normal concentration on an empty stomach; • Category 3 – increased plasma glucose concentration during random measurement and on an empty stomach. Despite the similarities with type 1 diabetes, acute and chronic complications rarely occur and are less severe. Cases of diabetic ketoacidosis are described, but rarely. Diabetic retinopathy occurs in approximately 15% of patients after 5 years and in 10% 10 years after the diagnosis of diabetes. More severe proliferative retinopathy, complicated by blindness, is rare. Microvascular nephropathy is described. However, it is too mild to cause kidney failure. Cases of ischemia in the central nervous and cardiac systems rarely occur due to factors including the shortened life expectancy of patients and the absence of concomitant diseases such as hypercholesterolemia and heavy smoking. Screening for diabetes in patients with cystic fibrosis Recommended annual PTG as a screening method for MADD in patients over the age of 12 years. PTTG is repeated after 12 months if it is normal or disturbed. With the patient growing symptoms of decreased lung function and weight loss, PTG is repeated earlier.