Irritable bowel syndrome in the Russian Federation: results of the ROMERUS multicenter observational study
Authors: Maev Igor V. , Okhlobystina Olga Z. , Khalif Igor L. , Andreev Dmitry N. 
Published: February 2023

Background. Irritable bowel syndrome (IBS) is one of the most common functional disorders of the gastrointestinal tract. According to Russian guidelines, a standard examination using laboratory and instrumental evaluation methods, including colonoscopy, should be performed to establish the diagnosis of IBS.
Aim. To characterize the Russian population of IBS patients.
Materials and methods. A multicenter observational prospective study ROMERUS was conducted at 35 clinical centers in the Russian Federation. The study included male and female patients aged 18 to 50 with a diagnosis of IBS based on the Rome IV criteria, with no signs of structural gastrointestinal disease. The follow-up duration was 6 months and included three patients' visits to the study site. During the study, data were collected on patients' demographic and clinical characteristics, medical history, and drug therapy. The secondary parameters included the assessment of the proportion of patients with a diagnosis of IBS confirmed by a standard examination among all patients meeting the Rome IV criteria, the evaluation of the change over time of the IBS symptoms, quality of life (QoL), and adherence to therapy. Characterization of the population was performed using descriptive statistics methods. The standard examination results were presented as the percentage of patients with IBS confirmed by the standard examination among all patients meeting the Rome IV criteria, with a two-sided 95% confidence interval.
Results. The study included 1004 patients with a diagnosis of IBS according to the Rome IV criteria, with 790 (78.7%) patients included in the final analysis. The mean age of patients was 34.07.5 years; they were predominantly female (70.4%), Caucasian (99.4%), married (55.1%), urban residents (97.5%) with higher education (64.5%) and a permanent position (74.9%). Patients enrolled in the study have low physical activity and lack a healthy diet. The smoking rate was 26.3%. IBS symptoms with predominant constipation (IBS-C) were observed in 28.1% of patients; 28.9% had IBS with predominant diarrhea (IBS-D), 11.9% had mixed-type IBS, and 31.1% had non-classified IBS. The main IBS symptoms were pain (99.7%), abdominal distension (71.1%), and fullness (36.8%). Biliary tract dysfunction (18.9%) and gastritis (17.2%) were the most frequently reported comorbidities. Prior to enrollment, 28% of patients received drug therapy. The most commonly prescribed drug during the study was mebeverine (54.1%). At 6 months of follow-up, there was a significant reduction of abdominal pain, bloating, and distention, and a twofold reduction in the incidence of constipation and diarrhea in the subgroups of patients with IBS-C and IBS-D, respectively. The overall QoL score measured by the IBS-QoL questionnaire increased from 83.0 to 95.2 points (p0.05) during the study. In the overall assessment of their condition, 69.6% of patients noted no symptoms and 25.3% reported marked improvement, 35% were asymptomatic according to the physician's overall assessment of the patient's condition, and 51.8% showed significant improvement.
Conclusion. IBS patients in the Russian Federation were characterized. The diagnosis of IBS, established following the Rome IV criteria, is confirmed by the results of a standard examination in 96.3% of patients. The Rome IV criteria for the IBS diagnosis make it possible to establish a diagnosis with a probability of 94.7%. For 6 months of follow-up, there was a clinical improvement with a decrease in the severity of symptoms and a QoL improvement.