Influence of Body Mass Index on hysterectomy rates after endometrial resection

Abstract

The influence of age on hysterectomy rates after transcervical endometrial resection (TCER) is well known (1). Other suggested, but inconsistently shown, risk factors are uterine size and the presence of leiomyomas (2). The influence of the Body Mass Index (BMI) on hysterectomy rates after TCER is unknown. The purpose of the present study was to investigate whether BMI was related to the frequency of hysterectomy after endometrial resection. From 1990 to 1996, a total of 367 women had a TCER procedure at the Department of Gynecology, Holstebro Hospital, Denmark. Women having a repeat TCER were only included with their first TCER. The criteria for TCER were at that time subjectively experienced meno-metrorrhagia, a uterine length <12 cm, and only minor submucous leiomyoma (maximum diameter 3–4 cm) with more than half of the mass projecting into the uterine cavity. No account was taken of the women's BMI status. GnRH-agonists were not used. Resection was carried out using a standard 9-mm resectoscope with glycine as distension medium. As part of another investigation on urological symptoms (3), all patient records were reviewed in 2005 using the central computerized patient registration system in Denmark, to clarify whether the women had a later hysterectomy. Statistical analysis was carried out with the SOLO software (BMPD, Los Angeles, USA). The Mann–Whitney test for unpaired analysis was used to test differences between two means, and the Kruskal–Wallis test for group means. Regression analysis was carried out with hysterectomy as the dependent variable, and BMI, age and operative data (uterine length, haemoglobin, glycin deficit, operative time, weight of the resected endometrium) as independent variables. Analysis of time until hysterectomy was by the Kaplan–Meier method. Potential variables affecting the outcome were compared using the Peto–Wilcoxon test after appropriate patient data grouping. Patient data investigated were BMI, age, cyclicity, parity, previous vaginal delivery, cesarean section, tubal sterilisation, preoperative knowledge of leiomyomas or adenomyosis, and histopathological endometrial phase. Values are given as medians with range, unless otherwise stated. A two-sided p-value <0.05 was considered significant. Patient characteristics and perioperative data are shown in Table I. A total of 96 women (26%) underwent hysterectomy after TCER. The association between BMI and hysterectomy rate is shown in Figure 1. Obese women had a significantly lower risk of hysterectomy than normal and overweight women. Obese women had a median age of 47 years (31–73) compared to 44 years (30–66) in the normal weight group (p<0.05). No other patient characteristics differed between obese and non-obese women. The cumulative hysterectomy rates for all women and different BMI groups after TCER. Rhomboids: BMI <25 kg/m2; squares: 25 kg/m2<BMI < 30 kg/m2; triangles broken: All BMI-classes; Triangles, full line: 30 kg/m2<BMI. Hysterectomy is the ultimate marker of treatment failure after TCER with a long-term prevalence of approximately 25%, as found in this study (2), (4). Age is the most important factor modifying this prevalence, given a normal-sized or only slightly enlarged uterus, with no or only minor submucous leiomyomas (1). In obese women, TCER is the primary surgical treatment of menorrhagia, since a high BMI is regarded by some, but not all investigators, as a risk factor for complications during or after major surgery (5). Theoretically, a higher estrogen level in obese postmenopausal women might contribute to long-term treatment failure after TCER. The increasing prevalence of obesity in the general population (6) makes it necessary to estimate subsequent hysterectomy rates in relation to the BMI. We found that, contrary to expectation, the risk was decreased in obese women after TCER, with a hysterectomy rate at the level described by others (4). Two factors may confound our results. First, reluctance to perform a hysterectomy in obese women may be present with individual gynaecologists, even though there are no specific guidelines for TCER or hysterectomy in relation to BMI. Secondly, obese women were slightly older than normal-weight women, which beforehand relates to a lower failure rate after TCER. These biases cannot, however, change the conclusion that a high BMI does not lead to a higher hysterectomy rate after TCER. Endometrial resection is an excellent first-line treatment of meno-metrorrhagia in obese women.