Impact of BMI on Recovery and Quality of Life Post-Revascularization in Peripheral Arterial Disease Patients

Introduction

Over 700 million people worldwide suffer from obesity. Obesity is defined as a body mass index (BMI) above 30 kg/m2 [1,2]. Overweight or obese people have increased levels of inflammatory cytokines, including interleukin (IL)-6, CRP, and TNF factor-α. The chronic inflammation that occurs in obese people leads to development of diseases such as hypertension, diabetes, and dyslipidemia [3]. Many studies have shown that obesity is one of the risk factors for diseases such as metabolic syndrome, type 2 diabetes, cardiovascular diseases, and peripheral arterial disease (PAD) [4–6]. Pacha et al [7] found patients with PAD who have a low BMI have higher in-hospital mortality (4.8% vs 1.2%) and more cardiovascular complications (7.9% vs 4.1%) after revascularization compared to those with normal BMI. Another study, involving over 1000 CLTI patients who underwent endovascular revascularization, showed that 3-year survival rates were lower for underweight patients (33.3%) than for those with normal weight (61.2%) or who were overweight/obese (69.8%) [8]. It is estimated that 65% of adults diagnosed with peripheral arterial disease are overweight or obese (BMI >25 kg/m2) [9]. Many authors [10–12] emphasize the relationship between obesity and PAD. Studies [13,14] have shown an association between obesity and the occurrence of intermittent claudication among people with a higher BMI and waist-to-hip ratio (WHR). Peripheral arterial disease is caused by atherosclerosis, which partially or completely restricts arterial blood flow to one or both lower limbs. It is estimated that more than 200 million people worldwide have been diagnosed with peripheral artery disease [15,16]. The incidence of PAD in people over 70 years of age is 20% [17]. The most important risk factors for PAD include: smoking, obesity, low level of physical activity, and diabetes [18,19]. A characteristic symptom of PAD is intermittent claudication, which is ischemic muscle pain in the lower limbs that occurs during walking. The more advanced the stage of PAD, the shorter the distance of intermittent claudication. Patients in the most advanced clinical stage have symptoms in the form of resting pain and lower-limb ulcers and are unable to perform even brief physical activities [20,21]. PAD is diagnosed based on symptoms such as lower-limb pain (foot, calf, thigh) that occurs during walking (intermittent claudication) and subsides after a short rest [17]. In addition, during a physical examination, the following are noted: paleness and coldness of the ischemic limb, loss of hair and muscle mass, and absent or weakened pulse in the lower limb. An objective method of diagnosing PAD is the assessment of the ankle-brachial index (ABI), in which a result of <0.9 indicates ischemia of the lower limb [22]. To determine the location of the artery obstruction, Doppler examination, CT angiography, and MRA are performed [23]. In the treatment of PAD, various methods are used, including: changing lifestyle and bad habits, reducing cardiovascular risk factors such as hyperlipidemia, hypertension, appropriately selected pharmacotherapy, and surgery [24]. Conservative treatment includes: smoking cessation, lowering cholesterol levels, and controlling diabetes and hypertension. Revascularization is most often performed in patients in whom other treatment methods have not achieved the desired results [25]. Peripheral arterial disease contributes to a decrease in the quality of life of patients, which is often associated with persistent pain and limited mobility [26,27]. The association of PAD with smoking, type 2 diabetes, or coronary atherosclerosis is well documented [28], but the impact of obesity remains controversial and the results of studies are divergent. The aim of this study was to assess the correlation between BMI and the improvement of parameters such as quality of life, pain-free walking distance (PFWD), and maximum claudication distance (MCD), in patients with peripheral artery disease 3 months after revascularization. Therefore, this study included 107 patients with peripheral arterial disease undergoing revascularization and aimed to evaluate the effects of body mass index on outcomes of quality of life, pain-free walking distance, and maximum claudication distance.

Material and Methods

ETHICS STATEMENT:

The consent of the Local Bioethics Committee of Nicolaus Copernicus University in Toruń and Ludwik Rydygier Medical College in Bydgoszcz was obtained (consent no.: KB 331/2019). The stud was were conducted in accordance with the Helsinki Declaration of 1975. Written informed consent was obtained from all study participants.

STUDY QUALIFICATION AND INCLUSION AND EXCLUSION CRITERIA:

The study was conducted at the Department of Vascular Surgery and Angiology at University Hospital No. 1 in Bydgoszcz, Poland, between 2019 and 2022. The study was prospective and observational. The study included 107 patients with diagnosed, symptomatic, peripheral arterial disease aged 18–80 years. Patients with clinical stage IIb according to the Fontaine scale (intermittent claudication distance <100 m) were qualified for the study. Peripheral artery disease was diagnosed based on a medical opinion and the ankle-brachial index (ABI <0.9). All participants were qualified for planned revascularization using the classic, endovascular, and hybrid methods. Patients were recruited for the study based on a review of medical records 1–5 days before the planned revascularization. On this basis, data such as patient age, type of planned revascularization, comorbidities, and symptoms were collected. The study initially included 117 patients with peripheral arterial disease, and the final analysis included 107 patients (Figure 1). Finally, patients were divided into 4 groups depending on BMI: patients with normal body weight (BMI 18.5–24.9), overweight patients (BMI 25.0–29.9), patients with obesity I (BMI 30.0–34.9), and obesity II (BMI 35.0–39.9).

The inclusion criteria for the study included: patient age ≥18 years and <80 years, medical diagnosis of PAD and medical qualification for planned revascularization within 1–5 days before the procedure, and clinical stage IIb according to the Fontaine scale.

Exclusion criteria for the study included: lower-limb amputation regardless of the level, type I or II diabetes, acute lower-limb ischemia, lower-limb ulceration or gangrene, impaired gait function caused by various diseases of neurological or orthopedic origin, III–IV heart failure according to the NYHA scale, rheumatic diseases, sensory disorders, sarcopenia, and obesity stage IV.

RESEARCH METHODS:

In this study, the following parameters were assessed: pain-free walking distance, maximum claudication distance, quality of life, Intermittent Claudication Questionnaire, and BMI. Patients were assessed twice: the first time 1–5 days before revascularization and the second time 3 months after an uneventful procedure.

ASSESSMENT OF INTERMITTENT CLAUDICATION DISTANCE: PFWD AND MCD:

The assessment of the intermittent claudication distance was performed on an electric treadmill (Schwinn Fitness 810, USA). For this purpose, the Gardner-Skinner protocol was used. Patients walked on the treadmill at a constant speed of 3.2 km/h. For the first 2 minutes of walking, the treadmill inclination angle was 0% and was increased by 2% every 2 minutes until the maximum angle of 12% was reached. Before the treadmill test, patients were familiarized with the course of the study and informed about wearing comfortable sports shoes. During the treadmill test, the pain-free walking distance and the maximum claudication distance were assessed. The first of these meant the distance the patient moved before the first pain in the lower limb occurred, and MCD meant the maximum pain in the lower limb, which prevented the patient from continuing walking on the treadmill.

QUALITY OF LIFE ASSESSMENT – INTERMITTENT CLAUDICATION QUESTIONNAIRE:

A standardized psychometric tool was used to assess the quality of life. The Intermittent Claudication Questionnaire consisted of 16 questions regarding symptoms, movement limitations in daily activities, and the impact of pain and intermittent claudication on these aspects. The answers to the questions were scored from 0 to 5 and summed up as a final score. The higher the score, the lower the patient’s quality of life. If the patient scored a total of 0 points, it meant a very good quality of life, while the maximum score of 80 points meant a very poor quality of life. In the final analysis, the results were converted into percentage values (80 points corresponded to 100%) [29].

BMI ASSESSMENT:

BMI was determined using a strictly defined method, which consisted of assessing the ratio of body weight to height. Body weight was measured using a calibrated scale. Patients were instructed to remove their shoes to obtain the most accurate result. The result was recorded in kilograms (kg). Height was measured using a stadiometer. Patients were asked to stand upright, without shoes, with the legs together, the heels touching the ground, and the head facing forward. Height was measured in meters (m).

The BMI value was calculated according to the formula:

Interpretation of results according to the WHO classification [30]:

STATISTICAL ANALYSIS:

The following formula was used to estimate the sample size:

Where

STATISTICAL METHODS:

Normality of data distribution was tested with the Shapiro-Wilk test. All results presented in the text and tables are expressed as averages±standard deviation or numbers. PFWD, MCD, and ICQ score parameters were compared using the Wilcoxon test for dependent samples when the condition of normal distribution was not met. Spearman analysis was used to assess the correlation between variables. The Mann-Whitney U test was used to determine statistically significant differences in distributions between 2 independent groups. P<0.05 was considered statistically significant. Statistical analysis was conducted using Python 3.12.7 (libraries: pandas version 2.2.3, scipy version 1.7.1).

Results

CHARACTERISTICS OF THE STUDY GROUP:

The study group included 107 patients aged ≥18 years and <80 years with peripheral arterial disease in clinical stage IIb according to the Fontaine scale. The average age was 66±6.7 years. The study included 88 men (82%) and 19 women (18%). The average BMI value in the entire study group was 28.02±4.35. Of the study participants, 30 had a BMI value <25 (28%), while 47 (44%) had a BMI value >30, indicating obesity. The study did not include patients with underweight (BMI <18.5) or obesity III (BMI >40).

COMPARISON OF RESULTS AND DIFFERENCE OF PFWD, MCD, AND ICQ 3 MONTHS AFTER REVASCULARIZATION ON INDIVIDUAL BMI GROUPS:

The least improvement in PFWD, MCD, and ICQ was achieved by patients with obesity II, while the most improvement was achieved by patients with normal BMI. The results are presented in Table 1.

PFWD, MCD, AND ICQ RESULTS IN INDIVIDUAL BMI GROUPS:

The improvement of PFWD, MCD, and ICQ results was compared among the individual BMI groups. A statistically significant difference was demonstrated between the assessed groups. Patients with normal body weight achieved a better improvement in the assessed parameters than patients with overweight and obesity II and II. At 3 months after the revascularization procedure, patients with obesity I and II did not significantly differ in improvement of PFWD (P=0.24). The results are presented in Table 2.

BMI CORRELATION RESULTS WITH IMPROVEMENT OF PFWD, MCD, AND ICQ:

The improvement of PFWD, MCD, and ICQ at 3 months after revascularization correlated statistically significantly with the BMI value (P<0.01). Obese patients with a higher BMI achieved a lower improvement in the assessed parameters than patients with a normal BMI. The results are presented in Table 3.

Discussion

LIMITATIONS:

This study did not evaluate detailed analysis of body composition and fat distribution. Physical activity level of patients was not assessed in the 3 months following revascularization, which could have influenced the PFWD and MCD measurement results 3 months after the procedure. This study assessed the quality of life of patients 3 months after revascularization, but it would be worthwhile to repeat it, for example, 1 year after the procedure, to assess long-term results.