Endometriosis and the risk of Systemic lupus Erythematosus: A report from Taiwan

The occurrence of systemic lupus erythematosus is higher in endometriosis patients.

Key Points

Importance:

• Clinicians should be well-informed about the association between systemic lupus erythematosus and endometriosis while managing either disease.

Highlights:

• A large Taiwanese nationwide population-based retrospective study reported an increased risk of systemic lupus erythematosus, an autoimmune disease in patients with endometriosis.

What's done here:

• Using Taiwan National Health Insurance research database, a retrospective cohort study was performed to reveal the association between endometriosis and Systemic Lupus Erythematosus (SLE).
• Endometriosis patients diagnosed by ultrasonography or laparoscopy (n=16.758) were compared to controls identified by matched comorbidities and characteristics (n=16.758).
• The cumulative probability of SLE in two study groups was estimated using appropriate statistical analyses.

Key results:

• A significantly higher incidence density rate of SLE was observed in the endometriosis group compared to the non-endometriosis group with a hazard ratio of 2.37.
• The robustness of the results was confirmed by focusing in the subgroup of laparoscopically diagnosed endometriosis patients.

Strength and Limitations:

• Data from large-scale randomly assigned samples and a 12-year follow up for estimation of SLE are strengths for reducing the selection bias and minimizing the miscalculation.
• The absence of laboratory data concerning immune system and hormonal profiles; the lack of data about some risk factors such as BMI, family history, smoking and alcohol consumption that may confound the association; paucity of patient numbers in some subgroups that prevent some subgroup analyses, endometriosis patients having more clinical visit for diagnosing SLE that may allow the diagnosis of SLE hence causing detection bias, are the limitations of the study.

Lay Summary

Systemic Lupus Erythematosus (SLE) is an autoimmune disease in which the immune system attacks its own tissues, causing widespread inflammation and tissue damage that affects mostly women, with an M:F ratio of 1:9. Recent evidence has also shown that endometriosis is a disease associated with immune system dysfunction. The association between those two diseases is not clear due to the limited number of cohort studies in the literature.

Fan et al., from Taiwan Chung Sang Medical University, used the Taiwan nationwide population-based data for a large retrospective nationwide cohort study to determine the association of SLE and endometriosis. Among 1 million female subjects, the authors first separated patients who were diagnosed with endometriosis by either ultrasonography or laparoscopy between 2000-2011, and 16758 endometriosis patients in this study group were matched based on the comorbidity and patient characteristics to a similar number of control patients to the women without the diagnosis of endometriosis.

The comparison of endometriosis group to the control group revealed a significantly higher incidence density rate and hazard ratio for the occurence of SLE in the endometriosis group, with an adjusted hazard ratio of 2.37. The reliability of the association was further confirmed in the subgroup of laparoscopically diagnosed endometriosis patients as the laparoscopy is the gold standard for endometriosis diagnosis, by finding a similar association.

This article entitled "Association berwwen endometriosis and risk of systenic lupus erythematosus" is recently published in the journal "Scientific Reports".

Research Source: https://pubmed.ncbi.nlm.nih.gov/33436777/