# A61 GLOBAL INCIDENCE OF APPENDICITIS: A POPULATION-BASED STUDY OF THE ORGANISATION FOR ECONOMIC CO-OPERATION AND DEVELOPMENT

## TL;DR

This study analyzed appendectomy rates across OECD regions from 2000 to 2023, finding significant geographic and temporal variations in appendicitis incidence.

## Contribution

The study provides a comprehensive analysis of appendectomy trends in OECD regions, highlighting differences between early and newly industrialized areas.

## Key findings

- Appendectomy rates decreased in 22 OECD regions and increased in 10 regions between 2000 and 2023.
- Rates ranged from 56.8 per 100,000 in Portugal to 165.6 per 100,000 in Switzerland.
- Variations in trends may be due to differences in diagnostic imaging and non-surgical treatment access.

## Abstract

The global incidence of appendicitis in 2019 was estimated at 228 per 100,000 person-years. However, temporal trends of appendicitis rates vary between early industrialized and newly industrialized regions.

To analyze annual appendectomy rates in regions of the Organisation for Economic Co-operation and Development (OECD) in the 21st century.

We conducted an observational population-based cohort study using data from 34 OECD regions from 2000–2023. OECD data provides country-level annual hospitalization rates for appendectomy per 100,000 person-years. We used Poisson regression to calculate Average Annual Percentage Change (AAPC) in appendectomy rates, with associated 95% confidence intervals (CI) for each region. CIs crossing 0% were defined as stable.

We observed geographic variation in appendectomy incidence rates, with rates ranging from 56.8 per 100,000 in Portugal (2023) to 165.6 per 100,000 in Switzerland (2022) (Table 1). Appendectomy rates significantly decreased in 22 regions and significantly increased in 10 regions, with AAPCs ranging from −4.25% (95%CI: −4.28, −4.22) in Italy to 1.46% (95%CI: 1.23, 1.68) in Norway (Table 1). AAPCs in Iceland were stable, and Latvia had insufficient data for time trend analysis.

In the 21st century, time trends of appendectomy rates across OECD regions displayed variation, with the majority decreasing. Geographic variability in rates and trends over time may be due to factors such as differential access to improved diagnostic imaging and non-surgical treatments.

Table 1. The Average Annual Percentage Change (AAPC) in appendectomy for the 34 regions of the OECD dataset with the corresponding year ranges for each region, confidence intervals, and associated average incidence per 100,000 person-years. All region AAPCs are significantly increasing or decreasing except Iceland and Latvia.

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