CHARACTERISTICS OF URIC ACID AND C-REACTIVE PROTEIN LEVELS IN PATIENTS WITH EROSIVE ESOPHAGITIS ASSOCIATED WITH OBSTRUCTIVE SLEEP APNEA SYNDROME

Background: Elevated serum uric acid (UA) levels are common among the adult population, are more frequently detected in men, and increase with age. C-reactive protein (CRP) is an early and sensitive indicator of the inflammatory process, and obstructive sleep apnea syndrome (OSAS) due to periodic hypoxia, sleep fragmentation, and increased oxidative stress leads to the development of a pro-inflammatory state in the body. The aim of the study was to evaluate the levels of UA and CRP in patients with erosive esophagitis associated with OSAS. Material and methods. To achieve the goal 107 patients with clinical or anamnestic data suggesting gastroesophageal reflux disease and/or OSAS and 48 patients in the control group were examined. Instrumental verification of erosive esophagitis (EE) and OSAS was performed based on video esophagogastroduodenoscopy with morphological confirmation and respiratory monitoring taking into account the existing recommendations. The levels of UA and CRP were determined in all patients. Reference values ware taken as a UA level <360 μmol/L regardless of gender, and a CRP level of 0 to 5 mg/mL. Results. Among patients with a verified diagnosis of EE, 53.85% were found to have OSAS, which is significantly higher than the prevalence of OSAS in the adult population. The analysis of UA levels in patients with EE revealed signs of hyperuricemia in association with OSAS, regardless of the degree of erosive damage in all groups and in male patients in the EE grade B group without association with OSAS. Differences in UA levels were found in women with grade B EE associated with OSAS compared to the group with grade B EE without OSAS. When analyzing CRP levels in the study groups, only patients with grade B EE combined with OSAS showed CRP levels above the reference values. Differences in CRP levels were found between male groups with grade A EE with OSAS and the group with grade A EE without OSAS. Conclusions. The high prevalence of OSAS among patients with EE determines the need to clarify its role in the development and progression of the disease. Hyperuricemia can be considered an early biomarker for the presence of OSAS in patients with EE, regardless of the severity of the erosive process, and is more informative in females. Elevated CRP levels in patients with EE associated with OSAS may indicate the negative impact of hyperuricemia and hypoxia on the development of aseptic inflammation and play an important role in damage to the mucous membrane of the distal esophagus.