Hypothesis / aims of study
In the United States, more than 8% of non-institutionalized women aged 65 and over report fecal incontinence (FI) episodes (1). It is now known that bilateral oophorectomy is not associated with improved survival at any age in average risk women (2). There are no studies to our knowledge that have clearly reported any association between estrogen status and FI. The purpose of this original study is to determine if a lack of estrogen (menopause per self-report, age ≥55 years, or status post bilateral oophorectomy) is a risk factor for FI. Additionally, to characterize other risk factors that may contribute to FI in women.
Study design, materials and methods
Following Institutional Review Board approval, our group conducted a retrospective chart review of a single tertiary care institution’s electronic medical record (EMR) between January 1st 1997 and January 1st 2017 of women who presented for outpatient care across a variety of specialties. Estrogen status and other clinical data were pulled from the EMR using the Informatics for Integrating Biology and the Bedside (i2b2) program. Variable data was re-confirmed by manual analysis of the EMR. FI diagnosis (via ICD-9 and ICD-10 codes) was used to dichotomize patients into two groups (YES-FI and NO-FI). We determined we would need a sample size of 152 cases and 152 controls that are age-matched, a two group chi-square test with a 0.05 two-sided significance level provided 80% power to detect risk factor odds ratios (i.e., for the association between risk factors of interest and case/control status) of 2.10 or greater.
Results
During the study period, a total of 482 women were analyzed, 241 cases (NO-FI) and 241 controls (YES-FI) (Table 1). Most (44%) of the cohort was Caucasian; the average age was 60.3(±16.8) years and the average body mass index was 26.1 (±6.2). The only significant difference between YES-FI and NO-FI women was seen in the race category.
YES-FI patients experienced more vaginal deliveries (1.7±1.8 vs 1.0±1.2; p<0.0001), reported history of gastrointestinal disorders (odds ratio, 5.6; 95% CI, 3.7 to 8.5), prior rectal surgery (odds ratio, 44.3; 95% CI, 6.0 to 325.4), history of urinary incontinence (odds ratio, 14.4; 95% CI, 7.4 to 27.8), and prior pelvic organ prolapse surgery (odds ratio, 14.2; 95% CI, 3.3 to 60.8). Having a history of bilateral oophorectomy showed significance (odds ratio, 2.0; 95% CI, 1.1 to 3.9).
Interpretation of results
1.) Our group has revealed for the first time a connection between estrogen status (having a history of bilateral oophorectomy) and FI. 2.) Known risk factors for fecal incontinence including vaginal delivery, history of gastrointestinal disorder, rectal surgery, urinary incontinence, and prolapse surgery have been confirmed in this study.