Appendectomy and Risk of Nonyphoidal Salmonella Infection in Children.

IMPORTANCE

The appendix is thought to have immunological functions. However, its role in protecting against enteric infections such as nontyphoidal Salmonella (NTS) remains unclear in children.

OBJECTIVE

To investigate whether pediatric appendectomy is associated with an increased hazard of subsequent NTS infection.

DESIGN, SETTING, AND

PARTICIPANTS

This was a nationwide population-based cohort study using data from Taiwan's National Health Insurance Research Database between January 1, 2000, and December 31, 2019. Children who underwent appendectomy were matched to children without appendectomy in a 1:4 ratio based on age, sex and index date. Data were analyzed from January 2000 to December 2019.

EXPOSURE: Appendectomy during childhood.

MAIN OUTCOMES AND MEASURES: The primary outcome was the incidence of NSA infection, defined as 3 outpatient or 1 inpatient diagnosis after the index date. The hypothesis that appendectomy increases susceptibility to NTS infection was specified before data collection. Cox proportional hazards models were used to estimate adjusted hazard ratios (aHRs).

RESULTS

The cohort included 18 654 children who underwent appendectomy (mean [SD] age, 10.04 (4.17) years; 11 883 [63.7%] male) and 74 616 matched children in the control group (mean [SD] age, 9.73 [4.30] years; 47 532 [63.7%] male). Children who underwent appendectomy had a significantly higher risk of NTS infection compared with children in the control group (aHR, 1.58; 95% CI, 1.17-2.13). The risk was pronounced in children younger than 5 years (aHR, 2.00; 95% CI, 1.35-2.97). Regarding follow-up periods, the risk was elevated but not statistically significant for 1 to 4 years (aHR, 1.51; 95% CI, 0.98-2.32) and 5 or more years (aHR, 1.78; 95% CI, 0.89-3.54).

CONCLUSIONS AND RELEVANCE: In this nationwide cohort study of children in Taiwan, pediatric appendectomy was associated with an increased hazard of NTS infection in the overall population and in particular among children younger than 5 years. These findings suggest a potential need for surveillance and preventive strategies in children following appendectomy, but further studies are warranted to develop and evaluate specific interventions.