Women who had appendectomy have increased risk of systemic lupus erythematosus: a nationwide cohort study
The appendix is involved in immune function, and an appendectomy may alter the immune system. Studies evaluating the relationship between previous appendectomy and the risk of systemic lupus erythematosus (SLE) are lacking. This nationwide cohort study investigated the incidence and risk of SLE in patients who underwent appendectomy. Patients aged > 20 years who received appendectomy from 2000 to 2011 were identified from the National Health Insurance Research Database and assigned to the appendectomy cohort. Patients without appendectomy were randomly selected from the NHIRD and assigned to the control cohort; they were frequency matched to each study patient at a 4:1 ratio by sex, age, and index year. All patients were followed until SLE diagnosis, withdrawal from the National Health Insurance program, or the end of 2011. We used Cox models to estimate the hazard ratio (HR) and 95% confidence interval (CI) to compare the risk of SLE between the appendectomy and control cohorts. From 23.74 million people in the cohort, 80,582 patients undergoing appendectomy and 323,850 patients without appendectomy were followed for 723,438 and 2,931,737 person-years, respectively. The appendectomy cohort had a 2.04-fold higher risk of SLE than the control cohort (adjusted HR = 2.04, 95% CI = 1.52–2.76). Women aged ≤ 49 years who underwent appendectomy had a 2.27-fold higher risk of SLE than the corresponding controls (adjusted HR = 2.27, 95% CI = 1.62–3.19). Women aged ≤ 49 years who underwent appendectomy have a significantly higher risk of SLE.
KeywordsAppendectomy Cohort study Systemic lupus erythematosus
This study is supported in part by the Ministry of Health and Welfare, Taiwan (MOHW107-TDU-B-212-123004), China Medical University Hospital (DMR-107-192).
We appreciated Sunny Chung for providing novel concept and collecting data.
All authors have contributed significantly, and all authors are in agreement with the content of the manuscript: Conception/Design: Wei-Sheng Chung; Collection and assembly of data: All authors; Data analysis and interpretation: All authors Manuscript writing: All authors; Final approval of manuscript: All authors.
The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Compliance with ethical standards
This study was approved by the Institutional Review Board of China Medical University and the Research Ethics Committee of China Medical University Hospital (IRB permit number CMUH-104-REC2-115).
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