# Sex Differences and Age Distributions in Invasive Treatments for Chalazion and Hordeolum in Japan: A 9-Year Nationwide Claims Study

## TL;DR

This study examines trends in invasive eyelid treatments in Japan, finding sex and age differences and a general decline in procedures over nine years.

## Contribution

The study provides new insights into demographic patterns and trends in eyelid treatments using nationwide claims data in Japan.

## Key findings

- Invasive treatments for chalazion and hordeolum showed sex differences, especially in younger age groups.
- Both procedures showed bimodal age peaks in males and females, with declining rates over time.
- Age-adjusted rates of procedures decreased annually, except for a rise in ITC cases among children aged 0–4 years.

## Abstract

To analyze nationwide trends and demographic patterns of invasive treatments for chalazion (ITC) and invasive treatments for hordeolum (ITH) in Japan.

A retrospective population-based cohort study.

Patients undergoing ITC or ITH procedures from 2014 to 2022.

Using the National Database of Health Insurance Claims and Specific Health Checkups Open Data Japan, we calculated annual numbers and rates of ITC and ITH per 100 000 person-years. Sex-stratified and age-stratified demographic peak patterns were analyzed, and annual trends were evaluated using linear and Poisson regression models.

Procedure rates, demographic distributions, and annual trends of ITC and ITH.

A total of 1 104 078 procedures (ITC: 465 379; ITH: 638 699) were recorded over the 9-year study period. The annual average rates were 40.9 for ITC and 56.2 for ITH per 100 000 person-years. Sex differences were prominent in younger groups: the overall female-to-male ratio was 1.1:1 for ITC and 1.0:1 for ITH, with a greater female predominance in youth (ITC: 2.0 at age 15–19 years; ITH: 1.7 at age 20–24 years). Invasive treatments for chalazion showed bimodal peaks in males (age 15–19 years: 40.9 procedures per 100 000 person-years; age 35–39 years: 56.0) and females (age 15–19 years: 80.6; age 30-34 years: 68.0). Invasive treatments for hordeolum showed bimodal peaks in males (age 10–14 years: 82.9; age 35-39 years: 72.1) and females (age 10–14 years: 102.4; age 30–34 years: 78.3). Both age-adjusted rates declined annually across all age groups and both sexes (P < 0.0167), except for an increase in 0–4-year-old ITC cases (P < 0.00088).

This study reveals sex-related and age-related demographic patterns and an overall decline in invasive eyelid procedures over the past decade and provides valuable insights into the epidemiology of common eyelid diseases and surgical trends in Japan.

The authors have no proprietary or commercial interest in any materials discussed in this article.