Regional equity and declining laryngeal surgery in Japan: A nationwide claims-based analysis from 2014 to 2022.

OBJECTIVE

The epidemiology of major otolaryngological surgeries in Japan remains unclear. This study investigated the national trends in three representative procedures, with a particular focus on laryngeal surgery, by analyzing demographic patterns and regional disparities.

METHODS

We performed a nationwide analysis using Japan's National Database of Health Insurance Claims and Specific Health Checkups between 2014 and 2022. Three representative otolaryngological procedures-laryngeal surgery, endoscopic sinus surgery, and tympanoplasty-were selected based on their relevance to board certification requirements for otolaryngology specialists. The data were stratified by age, sex, and prefecture, and annual surgery counts as well as rates per 100,000 person-years were calculated. Trends over time were assessed using the Jonckheere-Terpstra trend test and Poisson regression models to estimate the annual risk ratios (RRs). Regional disparities in surgery counts and distribution of board-certified otorhinolaryngologists were evaluated using the Gini coefficient.

RESULTS

Age-adjusted rates of laryngeal surgery declined significantly over time among males, females, and the overall population (risk ratio [RR] = 0.924, 0.908, and 0.919, respectively; P < 0.0167). Tympanoplasty showed a smaller but significant decline, while the trends for endoscopic sinus surgery were minimal. Subgroup analyses indicated significant annual decreases among individuals aged 20-89 years, who comprised the majority of laryngeal surgery cases for males, females, and both sexes combined (RR range: 0.875-0.957; all P < 0.0009). The Gini coefficients for all three procedures and the distribution of board-certified otorhinolaryngologists remained below 0.22, indicating low to moderate regional inequality.

CONCLUSIONS

This nationwide analysis identified distinct demographic trends and modest regional disparities in otolaryngological surgical care in Japan. The consistent decline in laryngeal surgery across major demographic groups suggests a systemic shift in clinical practice, rather than an isolated reduction in disease incidence. These findings highlight the importance of continued support from academic societies and coordinated policy efforts to maintain equitable access to surgical care.