Lower urinary tract symptoms in women with uterine fibroids at the university college hospital: a cross-sectional study in Ibadan, Nigeria

¹Genitourinary-Urogynaecology Unit, Department of Obstetrics and Gynaecology, Faculty of Clinical Sciences, College of Medicine, University College Hospital of Ibadan, University of Ibadan, Oyo State, Nigeria, ²Centre for Population and Reproductive Health, Ibadan, Nigeria

^&Corresponding author
Oluwasomidoyin Olukemi Bello, Genitourinary-Urogynaecology Unit, Department of Obstetrics and Gynaecology, Faculty of Clinical Sciences, College of Medicine, University College Hospital of Ibadan, University of Ibadan, Oyo State, Nigeria

Introduction    

Uterine fibroids are benign pelvic tumours that arises from smooth muscle cell of the uterus [1]. Fibroids causes a variety of unpleasant, life-disrupting urinary symptoms in women, such as urinary frequency, urgency and nocturia [2,3]. Despite been benign, and sometimes asymptomatic, fibroids are significantly associated with low quality of life and other gynaecologic morbidities [4]. These morbidities include abnormal uterine bleeding, dysmenorrhea, feeling of abdominal/pelvic discomfort or pain, abdominal/pelvic swelling, recurring pregnancy loss, pressure symptoms - bowel dysfunction and urinary symptoms [5-9]. The type and severity of fibroid-related symptoms depends on the size, number, and location.

Lower urinary tract symptoms (LUTS) describes various complaints related to urine storage, voiding and post-micturition symptoms and are defined from the individual's perspective [6,7]. LUTS usually result from conditions and diseases affecting the bladder and the urethra [10]. The most common LUTS in women with uterine fibroids are urinary urgency, frequency and nocturia [11,12]. Similarly, the pressure exerted by fibroids on the bladder as it increases in size, and the increase in intraabdominal pressure or during stress manoeuvres may predispose to stress urinary incontinence [13]. An increase in the prevalence of about 7% in stress urinary incontinence was observed in women with the large uterine fibroids [14]. These symptoms worsen the quality of life and health in affected women [2].

African women often have multiple, and large (uterus > 20-week size gestation) fibroids at the time of diagnosis because they present late. This increases morbidity and mortality in affected women [15]. In Nigeria, prevalence of uterine fibroids ranges from 3.2 to 25.9% with many women (88.7%) presenting with large fibroids [15-17]. Studies revealed fibroid sizes of more than 12 weeks are associated with the symptom of an incomplete bladder emptying, urinary urgency and urinary retention [13,18]. Case reports and series have also documented the relationship between uterine fibroids and voiding dysfunction, including acute urinary retention [5,19]. Despite the high prevalence of uterine fibroids among Nigerian women of reproductive age group, there is dearth of studies investigating lower urinary function in affected women prior to treatment, even though majority of the cases present as large pelvic or abdominopelvic masses. This study aimed to assess the lower urinary tract symptoms among women with uterine fibroids prior to treatment in a tertiary healthcare setting.

Methods     

Study design and setting

This is a prospective cross-sectional study that was conducted over a 6-month period from 2^nd September 2019 to 28^th February 2020. The study was conducted in the Urogynaecology unit in the Department of Obstetrics and Gynaecology at the University College Hospital, Ibadan, Oyo state, Nigeria. The Urogynaecology unit offers specialized service providing quality care to women with urinary and pelvic floor dysfunction.

Study population

The target population for this study were women with uterine fibroids. Consenting women who presented with clinical and radiological diagnosis of uterine fibroid in the gynaecology outpatient clinic were included in this study. All women who met the inclusion criteria were screened for urinary tract infection using a Multistix reagent dipstick. Those with trace, 1+, 2+, 3+ levels of leucocyte esterase and/or positive nitrites had a midstream urine microscopy, culture and sensitivity performed. Pregnant women, those with other gynaecological benign or malignant masses, women with a history of both vaginal and caesarean deliveries, and those with a laboratory-confirmed diagnosis of urinary tract infection were excluded from the study. The minimum sample size was calculated using the Kish and Leslie formula [n= Ζα²(pq)/d²] for descriptive studies where Z = 1.96 for a 95% confidence level, p is the proportion of participants with uterine fibroid among gynaecological patients (6.4%) [16], q = 1 - p = 0.936, and d = 0.05 (margin of error). The required minimum sample size at ensure adequate statistical power was 92. However, a total of 88 eligible women presenting during the study period were recruited which represents over 95% of the calculated sample size and was considered adequate for the analysis. All the participants had general physical and gynaecological examinations.

Data collection

Data were collected using an interviewer administered validated pelvic floor distress inventory (PFDI-20) and adapted to include demographic and medical characteristics as well as the clinical findings [20]. All participants who met the inclusion criteria completed the PFDI-20. The PFDI-20 also known as the pelvic floor disability inventory is a validated condition-specific symptom questionnaire that measures how much lower urinary tract, lower gastrointestinal tract and pelvic organ prolapse symptoms affect the quality of life of women. The PFDI-20 is comprised of 3 scales, which include the Urinary Distress Inventory-6 (UDI-6), Pelvic Organ Prolapse Distress Inventory-6 (POPDI-6), and the Colorectal-Anal Distress Inventory-8 (CRADI-8) all have a range of 0-100. The UDI-6 which is a 6-item scale was used to measure the overall urinary symptoms score by a numeric scale of response ranging from 0 to 4; 0 - no symptoms, 1) not bothered, 2) somewhat bothered, 3) moderately bothered, and 4) severely bothered [6,21].

Definition

LUTS were defined as one or combination of urinary frequency, urgency, stress urinary incontinence, and voiding dysfunction (difficulty in emptying bladder, difficulty urinating, pain, or discomfort in lower abdominal, pelvic, or genital area) as reported by the participants [22].

Statistical analysis

Data obtained were collated, entered, clean and analysed using Statistical Package for Social Sciences (SPSS) version 25.0 (IBM, Armonk, NY, USA). The baseline characteristics were summarized using means with standard deviation or proportion for continuous and categorical variables, respectively. For analysis, a response of 0 and 1 were grouped as none - “No symptoms” or “mild symptoms but not bothered, 2 as somewhat bothered, 3 and 4 as moderately to severely bothered. Overall, UDI symptoms score of 0 to 100 is obtainable and was evaluated by calculating the mean value of all answered items and multiplying it by 25 [18]. Analysis of variance (ANOVA) and t-test were performed to examine the relationship between independent variables and UDI-6 sub-scales of the questionnaire. The variables of clinical relevance were entered into a multivariable linear regression model to identify factors independently associated with UDI-6 scores. Regression coefficients (ß) with 95% confidence intervals (CI) were reported and P<0.05 was considered statistically significant.

Ethical consideration

The study was approved by the Oyo state Ethics Committee (AD13/379/1396). A written informed consent was obtained from each participant after careful explanation of the study´s objective and procedures. Privacy and confidentiality were maintained; all data were anonymized.

Results     

The participants' sociodemographic and clinical characteristics

Eighty-eight women consented to the study out of 102 recruited within the study period. The mean age and parity of the women were 38.1(SD 7.1) years and 1.1(SD 1.5), respectively. Majority of participants were married (76/88, 86.4%), had a tertiary level of education (59/88, 67.0%) and engaged in skilled occupation (47/88, 44.3%). Almost half of the women were nulliparous (43/88, 48.9%). The duration since diagnosis of uterine fibroids was =12 months in more than three-quarters (68/88, 77.3%) of the women and about two-third (57/88, 64.8%) of them presented with uterine size of >12 weeks. Out of thirteen women (13/88, 14.8%) who had previous fibroid treatment, almost all (12/13, 92.3%) had surgical treatment while (1/13, 7.7%) had medical management. The common symptoms of uterine fibroids at presentation were menstrual irregularities (47/88, 53.4%), infertility (43/88, 48.9%), abdominal pain (39/88, 44.3%) and abdominal swelling (33/88, 37.5%) (Table 1).

The distribution of participants' urinary symptoms

Equal proportion 28.4% of the women reported they were “somewhat” and “moderately to severely” bothered by frequent urination, 29.5% by urine leakage related to urgency while 26.1% were somewhat bothered by urine leakage related to physical activity. Also, 29 women (33.0%) were somewhat bothered by urine leakage drops and more than a third (37.5%) reported they were moderately to severely bothered by pain or discomfort in lower abdominal, pelvic, or genital area (Table 2).

The pelvic floor distress scores of the participants

On the pelvic floor distress inventory scales, the mean score was 18.4 ±1.74 on UDI-6 subscale and an overall mean score 39.7±34.8 on the PFDI-20 scale (Table 3).

The factors associated with urinary symptoms among the study population

Almost half (10/21, 47.6%) of the women who had delivered by caesarean section reported being somewhat bothered by urine drops. A significant relationship exists between urinary urgency with the women's mode of previous delivery(ies) (P=0.00). Significantly, a lower proportion (2/13, 15.4%) of women with previous fibroid treatment reported to be somewhat bothered by pain or discomfort in lower abdominal, pelvic, or genital area compared with 16.0% of the women without previous fibroid treatment (P=0.04). Almost half (47.4%), of the women with uterine size >12weeks significantly had moderate-severe pain or discomfort in lower, pelvic, or genital area (P=0.02), (Table 3).

The analysis of factors associated with UDI-6 scores among the study population

The uterine size and mode of previous delivery were factors significantly associated with urinary symptom score. Women with uterine size >12 weeks had statistically higher mean UDI-6 score 21.6±18.42 compared with those who had uterine size ≤12 weeks 12.4±13.54, t=-2.46; P=0.02. Women who delivered via caesarean section had statistically higher mean UDI-6 score 20.0±15.00 compared with those who had vaginal delivery 11.3±12.80, t=-2.11; P=0.04. On the linear regression analysis, uterine size (β = 3.98, 95% CI 1.48-6.47; P = 0.00), previous fibroid treatment (β = 3.68, 95% CI 0.36-7.00, P = .03), and mode of delivery (β = -2.29, 95% CI -4.08 - -0.51; P = .01) were independently associated with UDI-6 scores (Table 5).

Discussion     

This study assessed the lower urinary tract symptoms among women with uterine fibroids prior to treatment. Women with uterine size greater than 12 weeks had significantly higher UDI-6 scores compared with those with smaller uterine size. Additionally, women with history of caesarean section reported significantly higher urinary distress scores than those who had vaginal delivery. On multivariable regression analysis, larger uterine size, previous fibroid treatment, and mode of delivery were independently associated with higher UDI-6 scores.

The prevalence of LUTS among the participants was 19.3%. It was found that over a quarter of the women studied were "somewhat" bothered by the level of urinary frequency and "moderately to severely" bothered by level of urinary urgency while a third of them were "somewhat" bothered by leakage urine. However, more than a third experienced moderately to severely pain or discomfort in lower abdominal, pelvic, or genital area. The PFDI-20 mean score of 39.7 (SD 34.8) obtained in this study is lower than 45.5 (SD 31.9) reported in the Fibroids and Urinary Symptoms Study (FUSS) [23]. This implies the women had varying degrees of symptoms on the PFDI-20 subscales despite their homogeneity in urinary symptoms.

The overall mean UDI-6 score of 18.4 (SD 1.74) was obtained. This is similar to the findings of 19.0+15.8 in a study which evaluated a cohort of women prior to receiving fibroid treatment in the United States where majority of the women studied were Black [23]. Also, a prospective observational study of lower urinary tract symptoms before and after surgical removal of pelvic mass (fibroids and ovarian cysts) reported a low domain score in the UDI-6 preoperatively [13]. In the contrary, Berujon et al. and Shveiky et al. reported a higher mean UDI-6 score of 38.1 and 44.7 respectively [21,24]. The difference might be due to few numbers of women reporting LUTS in our study, difference in fibroid sizes and location which determine the intensity of pressure exerted on the urinary system, and their studies was mainly among the white racial population. Racial disparities have been found to be associated with the onset and severity of uterine fibroid symptoms and prevalence of urinary incontinence [25]. The main complaint of these women was menstrual irregularities and infertility. However, the women were mainly bothered by leaking urine in drops and pain or discomfort in lower abdominal and pelvic area. These symptoms are known to be associated with uterine fibroids [9,25].

In this study, women with uterine size of >12 weeks significantly had higher urinary symptom score compared to those with uterine size of 12 weeks and below. This is contrary to a study conducted at University of Southern California Gynaecology clinic, USA among women aged ≥18 years whose uterine fibroids were diagnosed by physical examination and ultrasound. The study showed that uterine size >12 weeks had no effect on the UDI-6 score [18]. Additionally, Cvach et al. found no association between pelvic ultrasound fibroid volume and the severity of lower urinary tract symptoms [13]. However, the observed result is similar to findings at the University of Pennsylvania Hospital, USA, where moderate to severe urinary urgency was reported in women with larger uterine volumes using the Bristol Female Lower Urinary Tract Symptom Scored Form (BFLUTS-SF) questionnaire [11]. Also, Ekin et al., found severity of LUTS with higher UDI-6 scores to be significantly associated with increase fibroid size [7]. It is expected that the large size of pelvic mass especially anteriorly located uterine fibroid is bound to exert pressure on the bladder or urinary tract, thus confirming the pain or discomfort in lower abdominal, pelvic, or genital area reported by the study participants [18,21].

On adjusting for confounders, it was found that previous fibroid treatment was associated with higher UDI-6 scores. Out of the 13 women that reported previous fibroid treatment, 12 had surgical management. In contrast, Berujon et al reported that surgical treatment appears to reduce urinary symptoms 6 weeks postoperatively [21]. The observed differences could be attributed to the study population in that this subset in the current study were women with recurrent fibroid. The number of fibroids and body mass index were insignificantly associated with severity of urinary symptoms among the women in this current study. Likewise, a similar study that examined the association between urinary symptoms, pelvic floor and fibroid symptoms with fibroid size and location found no significant association between these factors [26]. The Fibroids and Urinary Symptoms Study (FUSS) also found no correlation between fibroid size and pelvic floor distress score [23]. Though, there might be no association between the urinary symptoms and fibroid characteristics, it has been shown that urgency UI, stress UI, and frequency are prevalent in women having uterine fibroids [7,14,21].

This study is not without its limitations. Urinary continence and the pattern of urinary symptoms prior to the initial diagnosis of uterine fibroids were not assessed, and obtaining such information could be subject to recall bias. In addition, symptom severity was based on participants´ self-assessment, which may introduce subjective bias. Nocturia, an important urinary symptom, is not included in the UDI-6 instrument used in this study and therefore was not assessed. Despite these limitations, the urinary symptom questionnaire UDI-6 that was used has been validated in several studies [6,8,13,24]. This study provides the first local evidence in Nigeria to highlight the importance of evaluating lower urinary symptoms in women with large uterine fibroids. It is important that future studies should compare the pre and post treatment evaluation of LUTS as well as assessing the urodynamic functionality of women with large uterine fibroid or any other abdomino-pelvic masses that could impinge on the functioning of urinary bladder and or pelvic floor.

Conclusion     

Lower urinary tract symptoms are associated with large uterine fibroids, mode of previous delivery and previous fibroid treatment. Urge UI was the most severe of the urinary symptoms associated with large uterine fibroids. This underscores the need for evaluation of urinary symptoms in women presenting with fibroids. Early identification and management of associated LUTS may improve quality of life and inform individualized treatment decisions.

Competing interests     

The authors declare no competing interests.

Authors' contributions     

Conception and Design of the study: Oluwasomidoyin Olukemi Bello, Olatunji Okikiola Lawal, Rukiyat Adeola Abdus-salam, Imran Oludare Morhason-Bello and Oladosu Akanbi Ojengbede. Data analysis and interpretation: Oluwasomidoyin Olukemi Bello, Olatunji Okikiola Lawal and Rukiyat Adeola Abdus-salam. Manuscript drafting: Oluwasomidoyin Olukemi Bello and Olatunji Okikiola Lawal. Manuscript revision: Oluwasomidoyin Olukemi Bello, Olatunji Okikiola Lawal, Rukiyat Adeola Abdus-salam, Imran Oludare Morhason-Bello and Oladosu Akanbi Ojengbede. All the authors approved final version of the manuscript.

Tables     

Table 1: participants' demographics and clinical characteristics

Table 2: frequency of urinary symptoms using the UDI-6

Table 3: means, standard deviations and Cronbach's Alpha values of the pelvic floor distress inventory sub-scales

Table 4: association between the UDI-6 domains with the women's obstetric and fibroid characteristics

Table 5: factors associated with participants' UDI-6 scores using t-test, ANOVA, and linear regression analysis

References