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Correlation between the Ankle-Brachial Index and Body Mass Index in adult inpatients in the Internal Medicine ward of the University School Hospital of Honduras from May to July 2023

Andrea Agurcia1, Enoc Gonzalez1, Kelyn Vasquez1, Robersy Medina1, Marcio Madrid1,*, Carlos Santiago Pastelin1, Jose Isaac Zablah1, Antonio Garcia Loureiro2, Yolly Molina1, Salvador Diaz1, Carlos A. Agudelo1 and Jorge Valle-Reconco1
2    Departamento de Electrónica y Computación, Universidad Santiago de Compostela, España; [email protected]
*   Corresponding author: [email protected]; Tel.: (504) 2239-4292
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The ankle-brachial index (ABI) is a diagnostic tool to know the status of a patient in terms of peripheral vascular health. The body mass index (BMI) is another tool that helps health personnel know the patient's body composition. The data that have been considered are from 151 adult patients hospitalized in the internal medicine service of the University School Hospital. They found that the relationship between these two variables is weak; this is known through statistical techniques of probability study and correlation using the methods of Spearman and Pearson. It is concluded that ABI and BMI have a weak negative correlation. Additionally, age is not a factor that affects the ABI value since it can be affected by variables and conditions not considered in this study.
Keywords: ankle-brachial index; body mass index; peripheral vascular disease


The ankle-brachial index (ABI) is a low-complexity measurement that allows critical decision-making in the medical field, with significant importance in assessing the health of peripheral vessels and the cardiovascular system. The early detection of peripheral vascular disease has become a public health problem in recent years as it occurs in lifestyle-related diseases, including metabolic syndrome, diabetes mellitus and high blood pressure. This indicator is based on the relationship between systolic blood pressure in the ankle and systolic blood pressure in the arm, so it is expressed as a quotient.1-4
ABI is essential because it can diagnose peripheral arterial disease (PAD), a pathology that affects the blood vessels that supply the extremities, especially the legs. DBP is a marker of an increased risk of cardiovascular disease and adverse events like heart attacks and strokes. The ABI can detect early arterial obstructions by assessing the decrease in blood pressure in the lower extremities compared to the upper extremities, allowing timely intervention. The ABI also acts as a valuable tool for monitoring the effectiveness of treatments and the progression of chronic vascular diseases, leading to the implementation of appropriate preventive and therapeutic strategies.3-6
The ABI is interpreted according to the value; if it is greater than or equal to 0.9, it is normal; if it is between 0.8 to 0.9, it is a slight decrease; from 0.6 to 0.7, it is a moderate decrease; and less than or equal to 0.6 it is a severe decrease. It is essential to mention that a low ABI value may indicate an increased risk of complications such as ischemia, gangrene, and amputation.1-2
Body mass index (BMI) is an anthropometric measure to assess an individual's nutritional status. The BMI, according to its values, classifies people by their weight, so that a person is underweight if the BMI is less than 18.5, with healthy weight if their BMI is between 18.5 and 24.9, and overweight if it is between 25 and 29.9 and in obesity if the BMI is greater than or equal to 30. Because of this, BMI is useful for identifying people with an increased risk of developing chronic diseases, heart disease, type 2 diabetes, and some cancers.7-10
This research shows the correlation between ABI and BMI, which has been analyzed using standard statistical techniques and compared using a pair chart. The structure of this article contains this introduction, a section on methodology, results, discussion, and conclusions.


From a sample of 151 patients obtained by intentional non-probability sampling. Variables such as age, gender, weight, height, presence of chronic diseases such as type II diabetes mellitus and hypertension, and the value of the ankle-brachial index (ABI) and body mass index (BMI) have been captured. We have worked with a cross-sectional study design; the data were obtained between May and July of 2023 in the Internal Medicine ward of the University School Hospital in Tegucigalpa, Honduras.
The selection of patients for this study required meeting the following criteria: being hospitalized in the internal medicine ward, having blood chemistry of cholesterol and triglycerides, and voluntarily wishing to participate. The exclusion criterion for not being considered was being hospitalized for complications other than cardiovascular disease, not having cholesterol and triglyceride values in blood chemistry, or not wanting to participate.  
The procedure to take the ABI begins by lying the patient on a stretcher with the legs extended; the blood pressure in each ankle and arm is measured, obtaining the systolic pressure of the posterior tibial arteries and brachial systolic pressure. This measurement should be performed for each ankle and arm, grouped by left and right sides. ABI is calculated by dividing posterior tibial systolic blood pressure and dorsal ask by brachial systolic pressure, using the lowest value of both legs as ABI.1-2
BMI is calculated by dividing a person's weight measured in kilograms by the square of their average height in meters; equation 1 describes that formula. take special attention to the units mentioned:

BMI is an indirect measure of how much body fat a person has, although it is not an exact measure as it can be affected by muscle mass, body water, and other factors.9-10
The Python v3.10.3 programming language and the Notepad++ v7.9.3 text editor have been used to perform the statistical analysis of the collected data. Multiple libraries were used, including Matplotlib v3.7 and NumPy v1.18.; Pandas v2.1, SciPy v1.10.1, Seaborn v0.12.2, among others. Part of this analysis has been supplemented with the MedCalc v19.7.1 64-bit application. All these applications have been run on a personal computer with Microsoft Windows 10 64bit operating system.11-13


ABI values have a median of 0.9 with a standard deviation of 0.1697, a maximum value of 1.4, and a minimum of 0.5. The primary BMI statistic shows a median of 25.39 with a standard deviation of 3.5972, a maximum value of 38.04, and a minimum of 11.98. Using the Kolmogorov-Smirnov normality test,14-15, it was found that ABI measurements reject normality with a D=0.1553 statistic (p<0.0001). In this same sense, the BMI does not meet the criteria of normality, with a value D = 0.0925 (p>0.10).
In terms of gender, these correspond to 89 women and 62 men. The median age for women is 61 years, with a standard deviation of 16.04, with a maximum age of 88 and a minimum of 22 years. For men, the median age was 56 years, with a standard deviation of 16.57, with a maximum age of 87 and a minimum of 19 years. According to the Kolmogorov-Smirnov normality test, age has a normal behavior with a D=0.1011 statistic (p>0.10). The data have been represented by histograms, as shown in Figure 1.