Appendicitis links to the afterward subsequent psoriatic disease occurrence in Taiwan national health insurance research database: A population-based cohort study

Objective

To investigate the psoriatic disease risk among patients with previous appendicitis.

Methods

This study was a nationwide population-based case–control study about the association between the psoriatic disease risk among patients with a history of appendicitis in Taiwan. The study population consisted of newly diagnosed psoriatic disease with at least two outpatient visits, and the control group included those patients without psoriatic disease at the same index date. Patients with a previous diagnosis of appendicitis or who underwent appendectomy surgery prior to their psoriatic disease diagnosis were recorded. The odds ratio of psoriatic disease diagnosis in the two groups with and without a history of appendicitis were analyzed and compared.

Results

A total of 48 894 individuals diagnosed with psoriatic disease were matched with 292 656 controls by age and gender. Notably, the proportion of patients with a history of appendicitis or primary appendectomy was significantly elevated among those with psoriatic disease compared with the control cohort (both p < .05). On average, the occurrence of appendicitis preceded the index date by 3.3 ± 2.3 years. Multivariate analysis revealed a heightened incidence rate of psoriatic disease in patients previously diagnosed with appendicitis, periodontal disease, Charlson comorbidity index score (CCIS) ≧1, and ill-defined intestinal infections. This association persisted after adjusting for confounding factors, such as periodontal disease, CCIS, Salmonella, and ill-defined intestinal infections. The odds ratios for psoriatic disease in individuals with a history of appendicitis, periodontal disease, CCIS ≧1, and ill-defined intestinal infections were 1.16, 1.008, 1.69, and 1.23, respectively, with corresponding 95% confidence intervals of 1.03–1.31, 1.05–1.11, 1.65–1.74, and 1.20–1.26. These findings underscore the independent association between appendicitis and subsequent development of psoriatic disease, even after adjusting for relevant comorbidities and potential confounders.

Conclusion

Our research illustrates that appendicitis is associated with an increased likelihood of developing a psoriatic disease, despite several limitations. These limitations encompass variables such as dietary and smoking habits, alongside other potential confounding factors that were not fully considered. Moreover, inherent biases in utilizing national health insurance data, such as the absence of laboratory information, as well as the constraints inherent in a retrospective study design, should be acknowledged.