Comparison of the Effects of Cardiac Rehabilitation Between Obese and Non-obese Patients After Acute Myocardial Infarction.

Original Article Ann Rehabil Med 2016;40(5):924-932 pISSN: 2234-0645 • eISSN: 2234-0653 https://doi.org/10.5535/arm.2016.40.5.924 Annals of Rehabilitation Medicine Comparison of the Effects of Cardiac Rehabilitation Between Obese and Non-obese Patients After Acute Myocardial Infarction Seung-Kyu Lim, MD1, Jae-Young Han, MD, PhD2,3, Yu-Ri Choe, MD2,3 1 Department of Rehabilitation Medicine, Presbyterian Medical Center, Jeonju; 2Department of Physical and Rehabilitation Medicine, Regional Cardiocerebrovascular Center, Chonnam National University Hospital, Gwangju; 3 Center for Aging and Geriatrics, Chonnam National University Medical School, Gwangju, Korea Objective To evaluate the effects of cardiac rehabilitation (CR) on functional capacity in obese and non-obese patients who have suffered acute myocardial infarction (AMI). Methods Overall, 359 patients who have suffered AMI, and were referred for CR after percutaneous coronary intervention from 2010 to 2015 and underwent an exercise tolerance test before and after phase II CR were included in this study. The patients were divided into two groups: obese group with body mass index (BMI) ≥25 kg/m2 (n=170; age, 54.32±9.98 years; BMI, 27.52±2.92 kg/m2) and non-obese group with BMI <25 kg/m2 (n=189; age, 59.12±11.50 years; BMI 22.86±2.01 kg/m2). The demographic characteristics and cardiopulmonary exercise capacity of all patients were analyzed before and after CR. Results There were significant changes in resting heart rate (HRrest) before and after CR between the obese and non-obese groups (before CR, p=0.028; after CR, p=0.046), but other cardiopulmonary exercise capacity before and after CR was not different between the groups. HR rest (p<0.001), maximal metabolic equivalents (METs, p<0.001), total exercise duration (TED, p<0.001), and maximal oxygen consumption (VO2max, p<0.001) improved significantly in the obese and non-obese groups after CR. No difference in the change in the cardiopulmonary exercise capacity rate was detected between the groups. Conclusion CR may improve functional capacity in patients who suffered AMI regardless of their obesity. Keywords Obesity, Myocardial infarction, Rehabilitation, Exercise test Received March 14, 2016; Accepted May 3, 2016 Corresponding author: Jae-Young Han Department of Physical and Rehabilitation Medicine, Chonnam National University Medical School & Hospital, 42 Jebong-ro, Dong-gu, Gwangju 61469, Korea. Tel: +82-62-220-5198, Fax: +82-62-228-5975, E-mail: ORCID: Seung-Kyu Lim (http://orcid.org/0000-0002-6867-2896); Jae-Young Han (http://orcid.org/0000-0003-1672-8875); Yu-Ri Choe (http://orcid. org/0000-0001-5712-8724). This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/ licenses/by-nc/4.0) which permits unrestricted noncommercial use, distribution, and reproduction in any medium, provided the original work is properly cited. Copyright © 2016 by Korean Academy of Rehabilitation Medicine Effects of Cardiac Rehabilitation Between Obese and Non-obese Patients With AMI INTRODUCTION Obesity is a highly prevalent chronic condition associated with significant morbidity and mortality [1-3], including increased risk for developing cardiovascular diseases, such as hypertension, heart failure, arrhythmia and coronary artery disease (CAD), as it has maladaptive effects on various cardiovascular risk factors and adverse effects on cardiovascular structure and function [1,4,5]. The prevalence of obesity between 1976–1980 and 2009– 2010 among the world’s population aged between 20–74 years has more than doubled due to changes in diet and daily life activities [2,6]. Comprehensive cardiac rehabilitation (CR) is an effective secondary preventive post-myocardial infarction measure that can reduce the risk of re-infarction and cardiovascular mortality and morbidity [7]. The increase in the number of obese people has increased the overall risks for CAD. Overweight and obese patients account for >80% of CR participants [8,9]. Obesity significantly alters the effectiveness of CR because of the increased risk for CAD and adverse effects on cardiac structure. Studies on Westerners have reported that both obese and non-obese patients revealed significant gains in functional capacity from CR [5,10,11], and obese patients had smaller gains in functional capacity than non-obese patients [10,11]. Several studies have been performed on understanding the effects of CR on functional capacity in obese and non-obese Western patients; however, few studies have investigated the effectiveness of CR on functional capacity in Koreans. The classification and the characteristics of obesity in Koreans differ from those of Westerners. The World Health Organization (WHO) recommends using body mass index (BMI) as a screening tool for obesity and defined overt obesity as BMI >30 kg/m2. BMI between 25–30 kg/m2 is considered as overweight based on data from Western populations [12]. However, a BMI of 25 kg/m2 is considered as the cut-off for obesity in Koreans because these subjects have a higher percentage of body fat and thicker subcutaneous fat at a given BMI and are at substantial risk for comorbidities [13,14]. Results from the 2009–2010 National Health and Nutrition Examination Survey (NHANES) indicate that an estimated 33.0% of US adults aged ≥20 years are overweight (BMI 25–29.9 kg/ m2), 35.7% are obese (BMI 30–39.9 kg/m2), and 6.3% are extremely obese (BMI ≥40 kg/m2) [6]. However, the 2007 Korea National Health and Nutrition Examination Survey (K-NHANES) announced that the overall prevalence of obesity in Korean adults (BMI ≥25 kg/m2) is 36.7% in men and 25.6% in women (i.e., 4.1% of men and women have BMI ≥30 kg/m2) [15]. For this reason, we hypothesized that the effects of CR on functional capacity between obese and non-obese Koreans patients who have suffered an acute myocardial infarction (AMI) may differ from the effects in Westerners. Therefore, this study evaluated the effects of CR on functional capacity and BMI in obese and non-obese Korean patients who have suffered an AMI. MATERIALS AND METHODS Subjects This study recruited 359 Korean patients who were diagnosed with AMI, treated with percutaneous coronary intervention at the Department of Cardiovascular Medicine of Chonnam National University Hospital, and referred to the Cardiac Rehabilitation Center of Chonnam National University Hospital, Gwangju, Korea from 2010 to 2015. We divided the patients into obese group (BMI ≥25 kg/m2) and non-obese group (BMI <25 kg/m2) according to obesity criteria for Koreans. Before entering phase II CR, height and weight of each patient were measured, and BMI was calculated. All patients underwent exercise tolerance test (ETT) successfully before and after CR, and completely finished phase II CR in 6 weeks. Program All patients participated in home- or hospital-based phase II CR program, which consisted of risk (...truncated)