S2110 Adoption of New ICD-10 Codes for Microbial Overgrowth Syndromes: A Nationwide Analysis of Demographics and Treatment Trends

Introduction: In October 2023, the World Health Organization introduced International Classification of Disease (ICD) codes for intestinal microbial overgrowth syndromes including small intestinal bacterial overgrowth (SIBO) and intestinal methanogen overgrowth (IMO). Consensus on optimal treatment strategies is still evolving and lack of large-scale data presents challenges in accurately diagnosing, managing, and understanding the underlying risk factors for SIBO and IMO. We aimed to assess the utilization of these codes in the U.S. with a focus on demographic characteristics and treatment regimens. Methods: This retrospective cohort study utilized data from the TriNetX database, which provides access to de-identified medical records from over 130 million patients across 94 healthcare organizations in the US. The study included patients with ICD-10 codes K63.8219, K63.8211, K63.8212, K63.829, and K63.822. Considering the introduction date of the new ICD-10 codes, we analyzed data from November 2023 to May 2025. Demographics, including age, sex, ethnicity, and race, of each patient group, as well as the common treatment regimens used across these populations were analyzed. Results: The most common ICD-10 codes were “SIBO, unspecified” (K63.8219) and “IMO unspecified” (K63.929). The SIBO cohort consisted of 16,327 patients with a mean age of 49 ± 21 years (71.7% women). Regarding racial distribution, 76.1% were White, 7.1% were Black or African American, and 2.9% were Asian. Regarding ethnicity, 80.7% identified as non-Hispanic and 8.3% as Hispanic. Furthermore, 50% of the patients were treated with rifaximin, which was the most commonly used therapeutic approach. The IMO cohort consisted of 1,846 patients, with a mean age of 51 ± 18 years (72.1% women). Regarding race, 80.5% were White, 6.2% were Black or African American, and 2.7% were Asian; 85.6% identified as non-Hispanic and 6.1% identified as Hispanic. Additionally, 54.9% of the patients were treated with rifaximin and neomycin as the prevailing treatment approach. Conclusion: The widespread adoption of new diagnostic codes for microbial overgrowth is offering valuable insights into the burden, demographics, and treatment patterns of these patients on a national level. However, there is a pressing need to enhance education and awareness about the distinct subtypes of microbial overgrowth to promote accurate diagnosis and tailored treatment approaches.