Comorbidity Risks Among Women with Endometriosis

The incidence of developing comorbidities is higher among endometriosis patients compared to women without endometriosis.

Key Points

Importance

• Although studies show that endometriosis is associated with higher rates of a variety of conditions, evidence remains fragmented.
• There is a need to assess the association between endometriosis and co-occurring conditions in the same large, contemporary cohort.

What’s Done Here

• This study used data from a large, retrospective database of commercial insurance claims covering 2006 through 2015.
• A cohort of patients with incident endometriosis (cases) was compared with a cohort of matched patients without an endometriosis diagnosis (controls).
• 22 comorbidities were selected, including ones related to gynecological, mental health, gastrointestinal, cancer, and autoimmune conditions. Statistics used to analyze the results.

Key Results

• The analytic sample consisted of 26,961 cases and 107,844 matched controls
• The number of comorbidities per patient was statistically significantly higher among endometriosis case patients than their matched controls at the date of diagnosis of endometriosis.
• The risk of developing a comorbid condition was statistically significantly higher among incident endometriosis cases than among their matched controls for all 22 comorbidities.

Limitations of the Study

• It is not possible to determine whether associations between endometriosis and comorbid conditions are causal through this study.
• Documented comorbidities may be more common among endometriosis cases than controls because endometriosis patients had more contact with clinicians.
• The study did not account for patients using hormonal suppression, which affects the development of comorbidities.
• Endometriosis patients were identified using International Classification of Diseases diagnosis codes (ICD-9-CM), rather than histopathology of surgically removed lesions.

Lay Summary

Evidence demonstrates that endometriosis is associated with higher rates of conditions such as ovarian and other gynecological cancers, thyroid cancer, autoimmune diseases, asthma/atopic diseases, and cardiovascular diseases. However, as findings remain fragmented, there is a need to assess these associations based on the same large, contemporary cohort. Researchers from the United States conducted this study to determine the incidence of developing potentially common comorbidities among patients with and without endometriosis, hypothesizing that patients with endometriosis have a greater comorbidity burden.

This retrospective study recently published by Surrey et al. in Journal of Women`s Health, relies on commercial insurance claims covering 2006 through 2015. A cohort of patients with incident endometriosis was compared with a cohort of matched patients without an endometriosis diagnosis. The authors' evaluation was based on the presence of International Classification of Diseases, Ninth Revision diagnosis codes for endometriosis on medical claims to identify patients with endometriosis (cases) or without (controls).

The analytic sample consisted of 26,961 cases and 107,844 matched controls. The authors found that patients with endometriosis had “higher incidence of developing each of the 22 comorbidities considered, and for 9 of them, incidence rates were at least twice as high among endometriosis patients”. These 9 conditions included infertility/subfertility, ovarian cyst, uterine fibroids, pelvic inflammatory disorder, interstitial cystitis, irritable bowel syndrome, constipation/dyschezia, ovarian cancer, and endometrial cancer. The highest risk comorbidity in women with endometriosis was the diagnosis of interstitial cystitis and pelvic inflammatory disorder. The share of endometriosis patients with at least three comorbidities grew from 65% at diagnosis to 78% 1 year later and 85% 2 years later.

Surrey et al. report that the findings of this study are in line with other research revealing "endometriosis has been associated with increased risk of developing ovarian cancer, breast cancer, endometrial cancer, autoimmune diseases, and gastrointestinal diseases such as irritable bowel syndrome and constipation/dyschezia". However, they highlight that this study was based on retrospective analysis of data – “other studies with more detailed, prospective data collection found smaller or no associations among endometriosis and endometrial cancer, ovarian cancer, and breast cancer”. "An explanation for differences in findings may be due to reverse causality, residual confounding, and/or differences in outcome measurement", they added.

As a next step, the authors recommend investigating “the incremental contribution of specific comorbidities, while assessing which combinations of comorbidities co-occur most frequently”. They also note that “this study cannot distinguish whether endometriosis and its comorbidities share a common dysfunction or alternatively whether having endometriosis leads to subsequent comorbidities. Given the limitations of the current study, future research is needed to evaluate whether treating endometriosis can indeed delay or avoid the development of these comorbidities”.

Research Source: https://www.ncbi.nlm.nih.gov/pubmed/30070938