Assessment of Cardiovascular Risk Factors Pre-and Post-Bariatric Surgery

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1 Med. J. Cairo Univ., Vol. 84, No. 1, December: , Assessment of Cardiovascular Risk Factors Pre-and Post-Bariatric Surgery INAS T. EL-SAYED, M.D.*; MOHAMED D. SARHAN, M.D.**; MOSTAFA A. EL-SHAZLY, M.D.** and MAI D. SARHAN, M.Sc.* The Departments of Family Medicine* and General Surgery**, Faculty of Medicine, Cairo University Abstract Background: Obesity poses serious health consequences, and bariatric surgery remains the most effective and durable treatment. The goal of this study was to identify early changes in weight parameters, blood pressure, blood glucose level and lipid profile. A trial was made to correlate these changes with the degree of weight loss. Methods: A prospective cohort study was done including 30 obese patients (BMI 40 or 35 w th comorbidities). Demographic, clinical data, fasting and postprandial blood glucose as well as lipid profile were recorded pre-operatively as well as 2 weeks and 3 months post operatively. Results were statistically analysed and a correlation study was made between lost weight and changes in blood pressure, blood sugar and serum lipids. Results: A statistically significant reduction of body weight parameters occurred at 2 weeks and 3 months intervals postoperatively. Both systolic and diastolic pressures improved significantly. Twenty-one patients with hyperglycemia showed rapid improvement, but post-prandial hyperglycemia returned in 12 of them 3 months later. As regards dyslipidemiawhich was present in nearly 50% of patients, lipid profile improved significantly in most of them. There was a correlation between actual total body weight loss and percent change in cholesterol, triglycerides and HDL level, as well as fasting blood sugar. Conclusions: Bariatric surgery was followed by early significant changes in body weight parameters, improvement in blood pressure, blood sugar level and lipid profile. These changes entail a definite decrease in cardiovascular risk factors. Key Words: Obesity Bariatric surgery Weight parameters Hypertension Hyperglycemia Lipid profile. Introduction THE World Health Organization (WHO) [1] defined overweight as a Body Mass Index (BMI) to , and obesity as BMI 30. In 2013, the WHO databases documented that more than half a billion Correspondence to: Dr. Inas T. El-Sayed, The Department of Family Medicine, Faculty of Medicine, Cairo University adults worldwide are obese; more women than men are obese, with estimates of 297 million and 205 million, respectively [2]. In Western communities, overweight, obesity and related morbidities represent a heavy financial burden. In United Kingdom, for example, it was estimated to cost nearly 5 billion per year. These costs are expected to reach 10 billions by year Treatment of obesity specially by surgery may thus lead to significant cost savings to health care authorities in addition to its known clinical benefits [3]. With nearly 70 percent of their adult population overweight or obese, Egyptians are the fattest among African nations. It's also the 14 th fattest country in the world, according to the World Health Organization statistics issued for the year Among Egyptians above the age of 15 there are more overweight and obese females than there are males. According to WHO statistics, an estimated 76 percent of females in this age group are said to be overweight or obese, in comparison with approximately 64.5% of Egyptian males. Indicators reveal that the rate of obesity in Egypt has risen markedly over the past 30 years [4]. Many of the obese population are considered at high risk of developing the metabolic syndrome, cardiovascular complications are common among this group. Several definitions exist attempting to identify this syndrome and its multiple components [5]. Both obesity and type 2 diabetes are strongly associated with an unhealthy diet and physical inactivity. Physical and social environments are important influences on diet and physical activity behavior along with interrelated economic, psychological and cultural factors [6]. Sedentary behavior is also linked to obesity and a recent British 1309

2 1310 Assessment of Cardiovascular Risk Factors Pre-& Post-Bariatric Surgery study found that people with type 2 diabetes recorded greater amounts of sedentary time compared with their non diabetic counterparts [7]. There is growing evidence that obesity-associated coronary artery disease and myocardial dysfunction may be a direct consequence of the excess adipose tissue [8]. Numerous studies have demonstrated a direct association between excess body weight and Coronary Artery Disease (CAD). The BMI-CAD collaboration investigators conducted a meta-analysis of 21 long-term studies that followed more than 300,000 participants for an average of 16 years. Study participants who were overweight had a 32 percent higher risk of developing CAD, compared with participants who were at a normal weight. The investigators estimated that the effect of excess weight on blood pressure and blood cholesterol accounts for only about half of the obesity-related increased risk of coronary heart disease [9]. Ischemic stroke and coronary artery disease share many of the same disease processes and risk factors. A meta-analysis of 25 prospective cohort studies with 2.3 million participants demonstrated a direct, graded association between excess weight and stroke risk. Overweight increased the risk of ischemic stroke by 22 percent, and obesity increased it by 64 percent [10]. Obesity was significantly associated with death from CAD and cardiovascular disease. Women with BMIs of 30 or higher had a 62 percent greater risk of dying early from CAD and also had a 53 percent higher risk of dying early from any type of cardiovascular disease, compared with women who had BMIs in the normal range (18.5 to 24.9). Men with BMIs of 30 or higher had similarly elevated risks [11,12]. Management of obesity is traditionally divided into lifestyle modifications, pharmacological therapy, and bariatric surgery. However, bariatric surgery proved to offer the best results. The good news is that weight loss of 5 to 10 percent of body weight can lower blood pressure, LDL cholesterol, and triglycerides, and improve other cardiovascular risk factors [12]. Bariatric surgery has emerged as the most effective and durable strategy for successful weight loss in obese individuals. Bariatric procedures are associated with the greatest weight loss and metabolic benefits. Bariatric surgery is now recommended by WHO [1] as a definite treatment of morbidly obese patients after at least a 6-month trial of style modifi- cation therapy. It is also considered of great value for health service authorities from a financial point of view. Aim of the study: The aim of this study, is to evaluate changes in major metabolic and cardiovascular risk factors. A correlation between these changes and body weight loss were also studied. Patients and Methods In this work, patients undergoing bariatric surgery, namely sleeve gastrectomy, were followedup to evaluate changes in major metabolic and cardiovascular risk factors and correlate these changes with body weight parameters. The study was conducted in General Surgery Department, Kasr El-Aini Hospital during the period from January 2014 to the end of June Indications for surgery were in accordance with the following criteria: Patients who have BMIs of 40kg/m 2 or more, or between 35kg/m 2 and 40kg/m 2 with other significant disease that could be improved if they lost weight. All appropriate nonsurgical measures have been tried but have failed to achieve or maintain adequate, clinically beneficial weight loss for at least six months. Patients receiving or will receive management in a specialist obesity service. Patients who are generally fit for anaesthesia and surgery. Patients commit to the need for long-term followup. This study comprised 30 obese patients, with Body Mass Index (BMI) of 40kg/m 2 or more, or between 35 and 40kg/m 2 with diabetes, hypertension and/or dyslipidemia. Number of patients was limited as this operation is done at a limited scale in Kasr El-Aini Hospitals. Patients dictated to surgery were exposed to thorough medical history taking and laboratory investigations 2 days before the operation, 2 weeks and 3 months postoperatively. Investigations included: 1- Lipid profile including total cholesterol, LDL, HDL and triglycerides. 2- Fasting blood sugar and 2 hours postprandial.

3 Inas T. El-Sayed, et al Besides, a full blood count, liver enzymes, kidney functions were done as a preoperative routine. Data were compared to normal levels and postoperative data were also compared to the preoperative levels. Percentage changes were recorded. 3- Blood pressure assessment: Systolic, and diastolic arterial blood pressure were recorded preoperatively at 12 hours intervals under resting physical, and psychological conditions. This was repeated at the 2 weeks and 3 months assessment. Changes in these parameters were evaluated. Percent Excess Weight Loss (%EWL), percent Weight Loss (%WL), and change in BMI were considered as primary outcomes. Changes in obesity-associated comorbidities were collected as a secondary outcome and were based on their last known follow-up visit. The postoperative status of obesity-associated comorbidities was recorded as the same, improved, or in remission. Improvement was defined as a decrease in symptoms; a decrease in the number, dose, or frequency of prescribed medications; or improved measurements of laboratory results. Ethical considerations: All patients who participated in the study were informed about the details and objectives of the study. A written consent was taken from every patient. Statistical methods: Data was analysed using IBM SPSS Advanced statistics version 20.0 (SPSS Inc., Chicago, IL). Numerical data were examined as mean and standard deviation or median and range as appropriate. Qualitative data were expressed as frequency and percentage. McNemar test and sign test were used to examine the before-after data of qualitative variables. For quantitative data, comparison of repeated measures was done using paired-sample t-test. Pearson product-moment or spearman-rho method were used to estimate correlation between numerical variables as appropriate. All tests weretailed. A p-value <0.05 was considered significant. Results Table (1) shows the demographic and baseline clinical characteristics of the studied group. The baseline Body Mass Index (BMI) ranged from 35.1 kg/m 2 to 70.3kg/m 2 with a mean of 47.9 ±7.7kg/m 2. The mean excess weight in the studied group was 61.4± 18.3kg. Table (2) shows the values of blood pressure, blood sugar and lipid profile at baseline in the whole studied group. Table (3) shows the frequency of associated comorbidities and abnormalities of lipid profile at baseline in the studied group. The most common abnormalities were postprandial hyperglycemia and low HDL levels. Two weeks and three months after surgery, patients were re-evaluated regarding weight, blood pressure, blood sugar, and lipid profile. Changes in weight parameters are shown in (Table 4). Relative to the baseline weight there was a significant weight loss 2 weeks (p<0.01) and 3 months (p< 0.001) after surgery. This data are shown in Fig. (1). 2 weeks there was a significant decrease of blood pressure, blood sugar, serum cholesterol and LDL level (Table 5). The same table shows that after 3 months there was a significant decrease of systolic blood pressure, fasting blood glucose and all items of lipid profile. Table (6) shows that the frequency of high blood pressure and post prandial blood sugar decreased 2 weeks after surgery. Otherwise, no significant changes in HDL or triglyceride level were recorded. Three months after surgery, no case of hypertension existed. There was no significant changes in the frequency of other abnormalities except HDL level (p=0.005). The ratio between total cholesterol and HDL was used a measure of cardiovascular risk among the studied group (Table 7). The total cholesterol/ HDL ratio decreased significantly two weeks ( p= 0.001) and three months after surgery ( p<0.001). Table (8) shows the cardiovascular risk stratification of the studied group at baseline, two weeks and three months after surgery [13]. The risk decreased two weeks after surgery with a trend towards statistical significance (p=0.073), while a significant decrease of cardiovascular risk was observed three months after surgery relative to the risk after two weeks (p=0.002). On the other hand, absolute weight loss two weeks after surgery was negatively correlated with percent change in cholesterol and triglycerides and positively correlated with percent change in HDL level Figs. (2,3). Three months after surgery, absolute weight loss was positively correlated with percent change in fasting blood glucose level.

4 1312 Assessment of Cardiovascular Risk Factors Pre-& Post-Bariatric Surgery Table (1): Demographic and clinical characteristics of the studied group. Items Age (years) Sex: Male:Female Systolic blood pressure (mm Hg) Diastolic blood pressure (mm Hg) Fasting blood sugar Postprandial blood sugar Serum cholesterol LDL cholesterol HDL cholesterol Triglycerides High blood pressure Fasting hyperglycemia Postprandial hyperglycemia High cholesterol levels High LDL levels Low HDL levels Male to female ratio Weight (kg) Height (cm) Body mass index (kg/m 2 ) Ideal weight (kg) Excess weight (kg) High triglycerides levels Mean±SD/ratio/% Mean±SD 132.3± ± ± ± ± ± ± ±55.5 Number ± 10.4 Median (range) 120 ( ) 80 (70-130) 90 (80-195) 140 ( ) 186 ( ) 120 (56-211) 37 (26-58) 105 (71-360) Table (3): Frequency of associated abnormalities of blood pressure, blood sugar and lipid profile at baseline in the studied group. Percentage Table (4): Weight parameters two weeks and 3 months after surgery (mean±sd). Weight (kg) Weight Loss (kg) Body Mass Index (kg/m 2 ) %EBWL %TWL % EBWL % TWL 2 weeks 118.9± ±3.6* 43.8± ± ±2.7 : Excess Body Weight Loss (%). : Total Weight Loss. 4:26 2: ± ± ± ± ± 18.3 Table (2): Baseline blood pressure, blood sugar level and lipid profile in the whole studied group. 3 weeks 105.9± ±4.9** 39.04± ± ±3.8 * : p<0.01. ** : p<0.001 Table (5): Blood pressure, blood sugar level and lipid profile in the studied group preoperatively, two weeks and 3 months after surgery. Systolic blood pressure (mm Hg) Diastolic blood pressure (mm Hg) Fasting blood sugar Postprandial blood sugar Serum cholesterol LDL cholesterol HDL cholesterol Triglycerides High blood pressure Fasting hyperglycemia Postprandial hyperglycemia High cholesterol levels High LDL levels Low HDL levels High triglycerides levels Baseline ± ± ± ± ± ± ±6.9 *: p< **: p< ±55.5 Baseline 9 (30.0%) 5 (16.7%) 7 (23.3%) 9 (30.0%) 3 (10.0%) 2 weeks 3 (10.0%)** 4 (13.3%) 5 (16.7%)* 2 (6.7%) Mean±SD 2 weeks 117.2± 13.6* 75.2±10.9* 94.5±20.0** 129.9± 13.7* 164.9±32.1* 113.5±35.0** 38.4± ± (30.0%) 3 (10.0%) 3 weeks 114.5±9.7** 73.2± ± 18.6* 133.5± ±28.0* 107.8±33.3* 42.0±8.6* 93.5±25.2* Table (6): Frequency of associated abnormalities of blood pressure, blood sugar and lipid profile in the studied group preoperatively, two weeks and 3 months after surgery. *: p< **: p<0.05. ***: p< weeks 3 (10.0%) 12 (40.0%) 1 (3.3%) 7 (23.3%)*** 12 (40.0%) 1 (3.3%) Table (7): Total cholesterol/hdl ratio at baseline, two weeks and three months after surgery. Total cholesterol /HDL ratio Baseline Two weeks after surgery Three months after surgery p< /2 average risk Average risk 2 x average risk Baseline 12 (40.0%) 2 (6.7%) 4.97± ± 1.43* 3.48±0.89* 2 weeks 13 (43.3%) 1 (3.3%) Median (range) 4.69 ( ) 4.37 ( ) 3.29 ( ) Table (8): Cardiovascular risk stratification of the studied group at baseline, two weeks and three months after surgery. 3 weeks 27 (90.0%) 2 (6.7%) 1 (3.3%) p- value

5 Inas T. El-Sayed, et al Kg % change of cholesterol Baseline Weight after Weight after weight 2 weeks 3 months Fig. (1): Mean body weight of the studied group at baseline, two weeks after surgery and three months after surgery. r= p= Weight loss (kg) Fig. (2): Correlation between absolute weight loss and percent change of cholesterol two weeks after surgery. % change of HDL r=0.397 p= Weight loss (kg) Fig. (3): Correlation between absolute weight loss and percent change of HDL two weeks after surgery. Discussion In this study, the effects of bariatric surgery, specifically sleeve gastrectomy on body weight parameters as well as blood pressure, blood glucose level and lipid profile were evaluated. Nearly 86% of patients in this study were females and 14% were males. This distribution of sex was noticed in many other studies [14,15]. The mean age of participants in this study was 34.6 years with a range from years, demonstrating increased awareness of the of the value of surgery among adults and middle age obese population. The mean weight of the participants preoperatively was 130±20k.g with a mean BMI of 47.9 ±7.7 denoting that most of patients presented to surgery were in an advanced state of morbid obesity (BMI more than 40). Nine patients (30%) showed preoperative hypertension (blood pressure 140/90mmHg). This percentage is considered low compared with other studies that found a frequency of 44% [14,15]. On the other hand, in the preoperative assessment, fasting hyperglycemia was found in 5 patients (16%) and postprandial hyperglycemia in 16 patients (53.3%). It has been estimated that there is a seven times greater risk of diabetes in obese people compared to those with healthy weight [16]. Obesity has been attributed with being responsible for 44% of cases of diabetes [17]. Many theories have been postulated in explanation of this association [18-20]. Study of lipid profile in the preoperative period showed high total cholesterol levels in 7 patients (23%), high LDL in 9 (30%) and low HDL level in. Triglycerides level were high in only 10% of patients. Thus a state of dyslipidemia was evident in nearly one half of our patients. The cutoff levels were in accordance with the Adult treatment Panel III Guidelines of the National Heart, Lung, and Blood Institute [21]. Short term changes in weight parameters, and cardiovascular risk factors were recorded in this study. Weight parameters showed a statistically significant reduction in response to surgery two weeks after the operation. A further significant loss of weight was recorded 3 months postoperatively. It has been suggested that excess body weight loss percentage (%EBWL) is the standard parameter for assessment of body weight response to surgery [22]. In this study, the mean excess body weight loss percentage was 19.8% ranging from 9% to 32%. Total weight loss percentage was 8.3% (3-14.2%). Mean body weight of the study group dropped from 130±20k.g to ± 19k.g. These values were recorded just two weeks after surgery. Relative to the weight two weeks after surgery, there was a further significant weight loss three months later (p<0.001). The median excess body weight loss percentage (%TWL) was 18.3% ranging from 9.8% to 25.7%.

6 1314 Assessment of Cardiovascular Risk Factors Pre-& Post-Bariatric Surgery This study showed that the absolute weight loss (in k.g) has a moderate positive correlation with baseline weight two weeks and 3 months after surgery (r=0.3 & 0.4 respectively, p=0.026). Several studies showed that the mean weight loss reaches maximum in the first year postoperatively [23,24]. Owing to the short period of observation in this study we cannot comment on this statement. Certainly, compared with with other reports [25], we can admit that the rate of weight loss is maximum in this short period. Early body weight changes were accompanied by a significant improvement in glycemic control, hypertention and dyslipidemia. As regards blood pressure, out of 9 hypertensive patients only 3 remained as such after two weeks ( p=0.03). 3 months, no case of hypertension was recorded. The main change in blood pressure was in the first 2 weeks. Combined with improvement in lipid profile, this represents a very dramatic drop in cardiovascular risk. In a previous study [25] a 61.7% improvement in hyperlipidemic and 88% resolution of diabetes in obese patients undergoing bariatric surgery were reported. It is to be stressed that all hypertensive patients in this study reported that they stopped antihypertensive treatment in the two postoperative settings. Absence of statistically significant correlation between changes in blood pressure and weight parameters may refer to other mechanisms, mainly hormonal changes. It has been hypothised that sleeve gastrectomy results in decreased circulating leptin, an important regulator of sympathetic nerve activity, which modulates the CNS melanocortin. This may mediate the drop in blood pressure even before considerable drop of weight occurs. Early drop of hypertension and discontinuation of antihypertensive drugs were noticed by the same investigators [24]. These changes were recorded few days after surgery and were persistant at 1,3,6 months follow-up. There is a large body of literature demonstrating the early and mid-term effects of bariatric procedures on diabetes remission and improvement [26,27]. In this study fasting hyperglycemia was demonstrated preoperatively in 5 patients (16.7%) while postprandial hyperglycemia was evident in 16 patients (53.3%). Other investigators [28,29] gave an incidence of diabetes as 24-35% in obese patients prepared for bariatric surgery. In the present study, 2 weeks after surgery only 4 patients still had fasting hyperglycemia while only 5 of 16 patients still had postprandial hyper- glycemia. Unexpectedly, postprandial hyperglycemia was recorded in 12 patients after 3 months. This study showed that % EBWL was not correlated to blood sugar changes after surgery. Three months after surgery absolute weight loss correlated positively with percent change in fasting blood sugar level (r=0.39, (p=0.033) but not with postprandial levels. As expected dyslipidemia presented preoperatively in nearly 50% of patients in this study. Seven patients (23%) had high total cholesterol level (more than 200mg%). Thirty % of patients had high LDL levels (more than 130mg%). A low HDL level (less than 40mg%) was evident in 16 patients (53%). Triglycerides were high in only 3 patients. The association of obesity with dyslipidemia is well documented [30]. In diabetic patients the incidence of dyslipidemia rises to more than 70% [31]. In a recent meta-analysis study [32] it was found that there is a steady linear reduction in the risk of hyperlipdemia as BMI decreased. In the present study, there was a significant decrease in serum cholesterol and LDL levels as early as 2 weeks post surgery ( p less than & 0.02 respectively). No changes in serum HDL was observed. A further reduction in all aspects of lipid profile was noticed three months after surgery. The ratio between total cholesterol and HDL levels have been put forward as a measure of cardiovascular risk. A value of 4.4 was put as an average risk [13,21]. This ratio decreased significantly two weeks after surgery (p=0.001) and 3 months later (p<0.001). Absolute weight loss (in k.g) was negatively correlated with percent change in cholesterol, HDL and triglycerides. This was noticed in the first postoperative assessment. However this correlation was not evident with % EBWL. We have to stress that control of arterial blood pressure, reduced hyperglycemia, and correction of hyperlipidemic state in most of our patients provide further evidence that bariatric surgery enhances future cardiovascular health for obese individuals. Conclusion: We concluded that bariatric surgery can induce a significant improvement in cardiovascular risk factors including hypertension, hyperglycemia and dyslipidemia. These changes are evident early postoperatively even before gross body weight

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