Children who undergo appendectomy may face a higher long-term risk of nontyphoidal Salmonella infection, according to a nationwide cohort study from Taiwan. The findings add to growing evidence that the appendix may play a protective role in gut immunity, particularly during early childhood.

Using data from Taiwan's National Health Insurance Research Database, investigators compared outcomes among 18,654 pediatric patients who underwent appendectomy with 74,616 age- and sex-matched controls without appendectomy, with follow-up spanning up to 2 decades. Overall, pediatric patients who had an appendectomy experienced 1.58 times the hazard of subsequent nontyphoidal Salmonella (NTS) infection compared with those in the control group.

The association varied by age and was most pronounced in younger pediatric patients. In age-stratified analyses, patients younger than 5 years who underwent appendectomy had about twice the likelihood of developing NTS compared with age-matched controls. Risk estimates were also higher among patients aged 5 to 9 years, although findings were less consistent across analyses. In adolescents, estimates were imprecise and did not reach statistical significance, which the researchers attributed in part to lower event rates in older age groups.

Temporal analyses revealed a nuanced pattern. During the first year following appendectomy, the hazard ratio was lower and not statistically significant. Risk estimates were elevated but did not reach statistical significance during the 1 to 4 year and 5 year or longer follow-up periods, with the highest point estimate observed at 5 years or longer. Kaplan-Meier analyses demonstrated consistently higher cumulative incidence of NTS infection in the appendectomy group throughout the observation period. Male sex, rural residence, atopic dermatitis, and antibiotic exposure in the year prior to the index date were also independently associated with higher NTS risk.

Rather than focusing solely on epidemiologic associations, the study placed findings in the context of emerging understanding of appendix biology. The appendix contains abundant gut-associated lymphoid tissue and IgA-producing plasma cells and is increasingly recognized as a reservoir for commensal microbiota. Disruption of these functions during early childhood may impair mucosal immunity and increase susceptibility to enteric pathogens such as Salmonella.

"These findings suggest a potential need for surveillance and preventive strategies in children following appendectomy," wrote lead study author Meng-Che Wu, MD, of the Division of Pediatric Gastroenterology, Children’s Medical Center, Taichung Veterans General Hospital, Taichung, Taiwan, and colleagues.

The researchers declared no conflicts of interest. The study was supported by grants from Taichung Veterans General Hospital.

Source: JAMA Network Open