Risk of Self-Harm Among Individuals Diagnosed With Endometriosis: A Population-Based Cohort Study

Study Objective

To assess the association between endometriosis and the composite outcome of self-harm, which included suicide, intentional self-harm, and drug overdose.

Design

A population-based retrospective matched cohort study.

Setting

We used linked administrative data from a government-administered single-payer provincial healthcare system in Ontario, Canada between January 1, 2010, to July 1, 2022.

Patients or Participants

Women age 18 to 50 years with a first-time diagnosis of endometriosis.

Interventions

None.

Measurements and Main Results

Endometriosis exposure was determined using a validated set of diagnostic codes from physician billing and from outpatient and in-hospital visits. Individuals with endometriosis were matched 1:2 on age, sex, geography, and history of self-harm to unexposed individuals without a history of endometriosis. To account for psychiatric care utilization in the 2-years prior to study entry, we also matched endometriosis patients to controls based on a psychiatric utilization gradient score (0-no psychiatric utilization; 1-outpatient; 2-emergency care; and 3-hospital admission). The primary outcome was a composite of the first occurrence of suicide, intentional self-harm, or overdose. Secondary outcomes were the individual components of the composite. Cox regression models were used to generate hazard ratios with adjustment for all baseline covariates including in other comorbidities, income quintile, infertility, immigration status.

We included 168,159 individuals: 56,053 diagnosed with endometriosis (40.7% medically, 59.3% surgically) and 112,106 unexposed individuals. Compared to unexposed, patients with endometriosis were at increased risk of the composite outcome of self-harm (aHR 1.42, 95%CI 1.27–1.59, cumulative incidence of 2.47% vs 1.75%). Endometriosis conferred increased risk of intentional self-harm (aHR 1.37, 95%CI 1.22–1.54) and overdose (aHR 1.42, 95% CI 1.29–1.56) but not for suicide (aHR 1.21, 95%CI, 0.62–2.35), although only 42 suicide events were recorded over the study period.

Conclusion

A diagnosis of endometriosis is associated with an increased risk of self-harm. Mental health screening in the endometriosis population is warranted with targeted interventions for self-harm prevention.