Abstract C42: Investigating racial inequalities in rates of premenopausal bilateral oophorectomy using claims-based data, North Carolina 2011-2012
Authors: Robinson Whitney R. , Cheng Mariah M. , Doll Kemi M. 
Published: May 2016

Abstract
Background: Surgical menopause, or removal of both ovaries in premenopausal women, is associated with decreased incidence of and mortality from ovarian and breast cancer. As a result, racial differences in surgical menopause rates could unintentionally contribute to cancer disparities. Unfortunately, self-reported data on surgical menopause underestimate rates by 36%, and nationally representative clinical data exclude outpatient surgeries. Therefore, there are no reliable data on racial inequalities in surgical menopause.
Aims: This study estimated age- and race-specific rates of surgical menopause using claims-based data on every surgery conducted in North Carolina in 2011 and 2012.
Methods: Using data from North Carolina's Hospital Discharge Data and Ambulatory Surgery Visit Data, we enumerated, respectively, all inpatient and outpatient surgeries conducted in the state. We restricted the data to bilateral oophorectomies conducted among women aged 20-44 years who were not being treated for cancer. Claims-based procedure codes were used to identify oophorectomies. Diagnostic codes were used to exclude surgeries for malignant conditions. Census data represented the at-risk population. Deviance-adjusted Poisson models assessed whether rates differed by age or race.
Results: Oophorectomy rates were 15.0 per 10,000 women aged 20-44 years (n=4,904). The majority of surgeries, 71.3% (n=3,495) were conducted in outpatient settings. Rates increased with age (p&lt;0.01), ranging from 1.2 per 10,000 for 20-24 year-olds to 33.2 for 40-44 year-olds. Rates were higher among non-Hispanic White (17.4 per 10,000) than non-Hispanic Black (13.3) women (p&lt;0.01). In a sensitivity analysis including surgeries with unclear oophorectomy coding, rates were as high as 30.1 and 23.7 for White women and Black women, respectively.
Conclusions: In the first population-representative study to use clinical data and include outpatient surgeries, we show that surgical menopause rates are higher than previously reported. Additionally, today, these surgeries are primarily conducted in outpatient settings. Finally, rates are greater among non-Hispanic White versus Black women.
Impact: While overall rates of breast and ovarian cancer incidence decreased since 2000, Black-White racial inequalities worsened. Rates decreased among White women while remaining steady or increasing among Black women. Lower rates of surgical menopause among Black women may have the unintentional consequence of contributing to worsening racial inequalities in breast and ovarian cancer incidence and mortality.
Citation Format: Whitney R. Robinson, Mariah M. Cheng, Kemi M. Doll. Investigating racial inequalities in rates of premenopausal bilateral oophorectomy using claims-based data, North Carolina 2011-2012. [abstract]. In: Proceedings of the Eighth AACR Conference on The Science of Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; Nov 13-16, 2015; Atlanta, GA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2016;25(3 Suppl):Abstract nr C42.