# Association Between Allergic Rhinitis and Children With Appendectomy—A Nationwide Population‐Based Retrospective Cohort Study

## TL;DR

This study finds that children who have an appendectomy are more likely to develop allergic rhinitis, especially within five years after surgery.

## Contribution

The study is the first to show a population-based association between appendectomy and increased risk of allergic rhinitis in children.

## Key findings

- Children who had appendectomy had a 24% higher risk of developing allergic rhinitis compared to those who did not.
- The increased risk was most significant within five years after surgery and across various age and income groups.
- The findings suggest a need for careful evaluation of the necessity of appendectomy in children.

## Abstract

The appendix plays an important role to the human intestinal microbiota and immunity. Thus, appendectomy may alter immune function and intestinal biofilm. Allergic rhinitis is a common disease which is due to imbalance of TH2/TH1 cells and cytokine. The aim of this study was to evaluate the risk of allergic rhinitis after appendectomy in children.

The data source was the National Health Insurance Research Database (NHIRD), which is a large, population‐based database in Taiwan. We collected 4013 patients who had undergone appendectomy (case group) between January 1, 2000 and December 31, 2018 and matched them with 16,052 patients who had not undergone appendectomy (control group) by sex and age using proportional propensity score (PSM) at a ratio of 1:4 after excluding patients with a diagnosis of allergic rhinitis in the year prior to appendectomy. In addition, Poisson regression and subgroup analyses were used to investigate the relative risk of the development of allergic rhinitis after appendectomy in children.

The relative risk of subsequent allergic rhinitis in patients who had undergone appendectomy was found to be higher (RR = 1.24; p < 0.001) than in patients who had never undergone appendectomy. Subgroup analysis showed the risk of allergic rhinitis after appendectomy was significantly higher in patients aged 6–11 years and 12–18 years, and for both genders, living place, and lower income groups. When stratified by follow‐up duration, the risk of developing allergic rhinitis within 5 years of follow‐up was also significantly higher in the exposed group than in the control group.

Appendectomy was correlated with a 1.24‐fold increased risk of developing allergic rhinitis in children, especially within 5 years of follow‐up. Therefore, we suggest that the indication of appendectomy should be carefully evaluated to decide the best way to treat acute appendicitis.

Children who underwent appendectomy are at higher risk of developing allergic rhinitis than children without appendectomy, especially within 5 years after surgery.Therefore, the necessity of appendectomy should be carefully evaluated in children.Patients should be closely monitored for symptoms of allergic rhinitis after appendectomy and treated in time.

Children who underwent appendectomy are at higher risk of developing allergic rhinitis than children without appendectomy, especially within 5 years after surgery.

Therefore, the necessity of appendectomy should be carefully evaluated in children.

Patients should be closely monitored for symptoms of allergic rhinitis after appendectomy and treated in time.