# Epidemiology and treatment patterns of urachal remnants in adult patients with omphalitis: a nationwide claims-based study in Japan

## TL;DR

This study finds that urachal remnants are common in adult Japanese patients with omphalitis, especially young males, and often require surgery.

## Contribution

The study provides the first nationwide analysis of urachal remnants in adult omphalitis patients using claims data from Japan.

## Key findings

- Urachal remnants were found in 16% of adult omphalitis patients, with a male predominance.
- Surgery was performed in nearly 40% of cases, with laparoscopic procedures increasing after 2014.
- One case of urachal cancer was identified, highlighting the need for early diagnosis.

## Abstract

Urachal remnants are common in neonates and can persist into adulthood. However, their epidemiology in adults remains poorly characterized. We aimed to investigate the prevalence and clinical features of urachal remnants in adult Japanese patients with omphalitis using a nationwide claims database.

We analyzed data from the Japan Medical Data Center Claims Database (2005–2023) to identify patients  ≥ 15 years of age who were diagnosed with omphalitis. The prevalence of urachal remnants, associated diagnoses, surgical interventions, and time to surgery was examined, focusing on sex differences and age distribution.

Of the 11,477 patients with omphalitis, 1836 (16.0%) had urachal remnants, with a male-to-female ratio of 2.53:1. The prevalence peaked in males of 20–34 years of age, exceeding 30%. Surgical intervention was performed in 39.7% of the cases, with a median time to surgery of 2 months. The number of laparoscopic procedures increased after 2014 and surpassed that of open surgeries by 2018. One case of urachal cancer (0.054%) was also identified.

Urachal remnants are relatively common in adults with omphalitis, particularly in young males, and usually require surgery. Given the high prevalence and risk of recurrence, early imaging should be considered in adult omphalitis cases to support a timely diagnosis and intervention.