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ORIGINAL CONTRIBUTIONS

Received: November 2^nd 2015

Judged: May 2^nd 2016

Clinical and biochemical characteristics of patients with morbid obesity at the time of hospital admission and one year after undergoing bariatric surgery

Mario Molina-Ayala,^a Antonio Rodríguez-González,^a Alejandra Albarrán-Sánchez,^a Aldo Ferreira-Hermosillo,^a Claudia Ramírez-Rentería,^b Enrique Luque-de León,^a Ilka Bosco-Garate,^c Fernando Laredo-Sánchez,^d Roxana Contreras-Herrera,^e Julián Mac Gregor-Gooch,^f Carlos Cuevas-García,^g Victoria Mendoza-Zubieta^a

 

^aClínica de Obesidad y Cirugía Bariátrica

^bUnidad de Investigación Endocrinología Experimental

^cUnidad de Investigación en Inmunoquímica

^dConsulta Externa

^eDivisión de Cirugía

^fDivisión de Medicina

^gDirección Médica

Hospital de Especialidades, Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro Social, Ciudad de México, México

Communication with: Victoria Mendoza Zubieta

Telephone: 5627 6900, extension 21551

Email: vmendozazu@yahoo.com

Background: Three percent of Mexicans suffer from morbid obesity. Comorbidities associated to this condition diminish quality of life, increase mortality and health care costs. Despite bariatric surgery has specific indications and risks, it is the only treatment with effective long-term results. The aim of the study was to evaluate biochemical and clinical patient characteristics, both preoperatively and a year after they underwent bariatric surgery.

Methods: We carried out a quasi-experimental study that evaluates a sample of patients in the Clínica de Obesidad at Hospital de Especialidades (a third level hospital) between March 2011 and October 2015.

Results: A total of 150 patients were analyzed (60 % were women). Mean age was 41 ± 9 years and mean body mass index (BMI) was 48 kg/m² (42-53 kg/m²). Before surgery, type 2 diabetes mellitus (T2DM) was present in 31 %, hypertension in 60 % and 30 % of the patients were “metabolically healthy obese”. A year after surgery, the percentage of excess body weight loss was 66 %, T2DM and hypertension remission was 70 % and 50 %, respectively.

Conclusion: Bariatric surgery is an effective treatment to reduce excess weight. It improves biochemical, and clinical parameters in extreme obese patients

Keywords: Morbid obesity; Bariatric surgery; Type 2 diabetes mellitus; Hypertension

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According to the 2012 Encuesta Nacional de Salud y Nutrición (ENSANUT), in Mexico the prevalence of overweight this year was 38.8% and of obesity 32.4%, which shows that the majority of the population is significantly overweight. Extreme obesity, formerly called morbid, is defined as body mass index (BMI) ≥ 40 kg/m², and it occurs in 3% of Mexicans.¹ Due to the obesity epidemic, reports of extreme degrees are increasing. Currently the classifications of super-obesity (BMI 50-60 kg/m²) and super-super-obesity (BMI > 60 kg/m²) have been added.²

Obesity is associated with a reduction in both survival and quality of life.^3,4 People with extreme obesity die on average between 8 and 10 years earlier than those with normal weight,^5,6 and in Mexico this disease is responsible for 8 to 10% of premature deaths.^7,8 It is estimated that this condition generates 1 to 3% of total health expenditure in most countries.^6,9 Comorbidities contributing to this deterioration are hypertension (HT), cerebral vascular events, cancer, diabetes mellitus type 2 (DM2), vesicular disease, dyslipidemia, osteoarthritis, gout, and obstructive sleep apnea/hypopnea syndrome, among others.^1,10,11

Although prevention and information programs in Mexico are vital to avoid the continuous increase in the prevalence of obesity, the treatment of patients currently suffering from extreme obesity continues to pose challenges to researchers around the world.^6,12 While there are drugs approved for the treatment of obesity, such treatments cannot be used for a long time, they have adverse effects, and the weight is regained if the patient does not make lifestyle changes.¹³

Bariatric surgery has proven to be the only treatment for obesity that generates large short-term changes in weight and can maintain this condition long-term; it also reduces the risk of co-morbidities and allows the patient's reintegration into social, work, and family life, which leads to improved quality of life. The bariatric procedures used are restrictive procedures (gastric banding, sleeve gastrectomy), malabsorptive (biliopancreatic diversion), and mixed (gastric bypass).¹⁴ However, the patient to undergo these surgeries should be carefully selected, and once operated on requires lifelong monitoring of a multidisciplinary team to give continuity to the nutritional plan, vitamin supplementation, and long-term medical monitoring.¹⁵ Therefore, not all patients are candidates for surgical management and not all centers are enabled to perform these surgeries. Adequately assessing patients who are candidates for surgery and the appropriate type of surgery for these patients remains controversial among different groups worldwide. Some measures of efficacy of surgical treatment are short-term assessment of the percentage of excess weight loss (% EWL), the improvement or remission of metabolic comorbidities, cardiovascular risk reduction, and improved quality of life. The current criterion for determining whether bariatric surgery was successful is a ≥ 50% EWL and improvement in comorbidities; however, this measure expresses very limited benefit on other health areas.¹⁶ For this reason, the different institutions involved in the management of extreme obesity have their own evaluation parameters, which depend on the type of population they serve; this necessitates that each group of bariatric surgery present its results and evaluate the effectiveness of its processes.

In our country, 30% of the population is enrolled with the Instituto Mexicano del Seguro Social (IMSS). The Unidad Médica de Alta Especialidad Hospital de Especialidades of the Centro Médico Nacional Siglo XX (UMAE HE CMN SXXI), through the Obesity and Bariatric Surgery Clinic, provides multidisciplinary care to patients with extreme degrees of obesity who are candidates for surgical treatment. The aim of this study was to describe the clinical and biochemical characteristics of a sample of patients of the Obesity Clinic that have been operated on between 2011 and 2015 and to evaluate the short-term effect (one year) of bariatric surgery on the most common metabolic comorbidities.

Methods

A sample of patients undergoing bariatric surgery in the period between March 2011 and October 2015 at the Hospital de Especialidades of the Centro Médico Nacional Siglo XXI was selected. These patients underwent gastrectomy or laparoscopic gastric bypass (LGB), depending on the characteristics of each patient and the surgeon's decision. Before surgery, patients completed a short interview recording their age, adherence to diet, exercise (defined as at least 30 minutes of physical activity, different from their everyday activities and practiced three or more times a week), smoking (one or more cigarettes a day), family history of type 2 diabetes mellitus, hypertension, obesity or dyslipidemia, level of education, and current occupation. Information regarding previous illnesses such as hypertension, impaired glucose metabolism (defined as impaired fasting glucose or impaired glucose tolerance), type 2 diabetes mellitus, and dyslipidemia, was obtained from medical records.

As for anthropometric evaluation, a single researcher used the same calibrated scale with an integrated stadiometer for all anthropometric measurements. The height (meters) and weight (kilograms) were measured at the initial visit, as well as before surgery, and 12 months later. The body mass index (BMI) was calculated with the weight divided by the square of height. Blood pressure was assessed in the left arm, after 10 minutes of rest, during fasting, without the patient smoking tobacco or drinking coffee for a week before measurement. The sphygmomanometer was calibrated and their values ​​were averaged after two different measurements, with five minutes difference between them.

For biochemical assessments, biochemical markers were determined before surgery and one year after. For biochemical determinations, all patients completed a fasting period of 12 hours. Laboratory studies were obtained using a sample of 6 mL of blood in a BD Vacutainer container (BD Franklin Lakes, New Jersey, USA), centrifuged at 3150 × g for 15 minutes, and the serum was assayed with a kit for glucose, cholesterol, HDL-C, and triglycerides (COBAS 2010 Roche Diagnostics, Indianapolis, USA) using photocolorimetry with a Roche Modular P800 spectrometer (2010 Roche Diagnostics, Indianapolis, USA). HDL-C samples were processed with modified polyethylene glycol and dextran sulfate enzymes, and analyzed by the same photocolorimetry technique. Glycosylated hemoglobin (HbA1c) was evaluated with turbidimetric immunoassay (COBAS 2010, Roche Diagnostics, Indianapolis, USA). The calculation of LDL-C was done with Friedewald’s formula: LDL-C = CT mg/dL - (HDL-C mg/dL + Triglycerides mg/dL/5), provided that triglycerides were < 400 mg/dL. Laboratory tests were performed preoperatively and at 1, 3, 6, and 12 months after surgery, although this study only reports the values ​​before and 12 months after surgery. 

Remission of type 2 diabetes was defined as established by the International Diabetes Federation: glucose < 100 mg/dL, glycated hemoglobin (HbA1c) < 6.5% without medical treatment for a year after bariatric surgery; HT remission, blood pressure control < 130/80 mm Hg without antihypertensives; and dyslipidemia control according full lipid profile of HDL, LDL and total cholesterol.

For statistical analysis, quantitative variables were described using measures of central tendency and dispersion by data distribution. The qualitative variables were described by frequencies or percentages. The Shapiro-Wilk test was used to establish normal distribution of quantitative variables. Paired t-test or Wilcoxon rank sum was used for qualitative variables, and the McNemar test for associations between quantitative variables. P < 0.05 was used to establish statistical significance. For data analysis we used SPSS, version 17.0 and STATA, version 11.0.

Results

We analyzed 150 patients with a mean age of 41 ± 9 years; 60% were women, and 30% had super obesity or super super obesity. About 50% had the maximum weight reached in life and had a history of 10 to 15 years with severe obesity. The median waistline in the study group was 133 cm with interquartile ranges (IR) of 120-146 cm, with a median of 145 cm (IR 136-154 cm) in men and 125 cm (IR 115-136 cm) in women. The median height of the group was 1.63 m (IR 1.57-1.72 m); men were 1.72 m (IR 1.69-1.79 m) and women 1.58 m (IR 1.54-1.67 m). The median weight was 127 kg (IR 109-142 kg); for men 145 kg (IR 129-170 kg) and for women 115 kg (106-130 kg). The median BMI was 48 kg/m² (IR 42-53 kg/m²); men with 49 kg/m² (IR 43-59 kg/m²) and women with 45 kg/m² (IR 41-52 kg/m²). 86% of patients underwent LGB surgery (8% as revision of a purely restrictive procedure) and 14% gastrectomy.

As for important background, 85% of patients had dietary adherence greater than 80%, 31% had regular physical activity (defined as at least 150 minutes of moderate activity per week) and 18% smoked. As for family history of importance, 70% had a history of DM2, 76% of HT, 27% dyslipidemia, and 74% overweight or obesity.

As for education level, 34% of patients had upper secondary education, 32% a college degree, 20% secondary school, 9% primary school, and 2% were illiterate. As for current job, 50% were employed in different private companies, 18% belonged to the economic/administrative area, 20% were homemakers, 5% of retirees of the institution, 3% health workers, and 4% students.

The prevalence of the most frequent co-morbidities upon arrival at the Obesity Clinic was as follows: 31% had DM2, 62% HT, and 33% dyslipidemia, while 30% were "metabolically healthy."

In the evaluation of results for the first postoperative year we found a statistically significant improvement in all biochemical parameters (Table I). As for the remission of the most frequent comorbidities, 70% had remission of type 2 diabetes, 50% remission of HT, and 11% remission of dyslipidemia.

A steady reduction in body weight measurements was found at 1, 3, 6, and 12 months: weight of 109 kg (111-121 kg), 98 kg (88-109 kg), 91 kg (80-101 kg) and 79 kg (71-91 kg), respectively (p < 0.001 compared to the initial weight). BMI reduction found in the measurements at 1, 3, 6 and 12 months was 41.9 kg/m² (37.8-45.8 kg/m²), 37.7 kg/m² (33.3-41.6 kg/m²), 34.4 kg/m² (29.7-39.1 kg/m²) and 30.3 kg/m² (27.4-34.6 kg/m²), respectively (p < 0.001 compared to baseline BMI). This means that the degree of obesity was reduced from extreme obesity to overweight or stage I obesity at 12 months from the surgical procedure, with the greatest reduction in weight and BMI in the first quarter after surgery. The median EWL% the first year was 65% (IR 55-84%); in men it was 59% (IR 50-74%) and women 70% (IR 59-84%).

Discussion

Obesity has acquired pandemic proportions in the last decade and has become a priority issue for health, research, and the economy in the world. At the Hospital de Especialidades in the UMAE CMN SXXI, a clinic was established in 2008 that is currently the only multidisciplinary care team for patients with severe obesity in the IMSS.

The creation of multidisciplinary teams to care for complex diseases such as extreme obesity consumes time and resources; however, it can provide significant benefits for both the patient and health systems. These benefits should be assessed and restructured periodically, depending on the results obtained in each center and advances in science.

Comparing our results with other centers in Mexico who have more years of experience treating patients with extreme obesity, Reyes-Pérez et al. reported similar results in patients after Roux-en-Y gastric bypass (RYGB) in a private environment. The age of the patients was 40.1 ± 11.5 years, women accounted for 42% of the group, and initial BMI was 42 ± 6.5 kg/m²; researchers found comorbidities in 58% of patients. We note that our population has a greater BMI and we have more women, similar to that reported in the ENSANUT.¹⁷ The Instituto Nacional de Ciencias Médicas y Nutrición "Salvador Zubirán" analyzed the patients after RYGB and found younger subjects (38 ± 10 years), which is similar to our study, with a mean BMI of 48 ± 6 kg/m². The weight reduction in patients within a year of surgery was 20% and EWL % was 73%, similar to our results. In addition, patients had 65% remission of DM2 and 64% HT, also similar to this study. Regarding dyslipidemia these authors made a separate analysis of lipid profile cholesterol, HDL, LDL, and triglycerides, and we define remission as all parameters within normal ranges. Note that in our group of patients, 14% underwent gastrectomy, which has different results in terms of EWL% and improvement of comorbidities when compared with BGL. ^16,18 With these results we see that patients at the institution have a higher degree of obesity than in the private sector, which suggests that they have increased cardiovascular risk and reduced quality of life and, therefore, could be benefited more with the surgical management; however, these improvements in our population remain to be demonstrated long-term.

The benefit is observed not only in those who achieved weight goals or remission of comorbidities presented in accordance with international standards, but the overall group showed an overall reduction of biochemical parameters associated with cardiovascular risk. For example, there was a 19% reduction in fasting glucose compared to the group baseline; insulin decreased so much that HOMA showed an improvement of 6.4 to 1.38 (78% reduction); the same thing happened with uric acid, total cholesterol, LDL, and triglycerides. It is also important to note that the whole group had an increase in HDL cholesterol, associated with cardiovascular risk when low in diverse populations, and consistently low values have been reported in Mexican populations, even in apparently healthy individuals.¹⁹ Having a high prevalence of obesity in the country and finding that populations of Mexican descent in other countries have a higher cardiovascular risk compared with other immigrants or residents of the country studied,^20,21 it is easy to assume that our population should be studied and handled with utmost care. However, it remains to be proven that Mexican patients with severe obesity represent a truly different population from other countries and even other ethnic groups, which would also involve the development of specific strategies for its management in this country. Extensive epidemiological studies as well as long-term follow-up of specific groups and help from molecular biology support this assumption.

Previously the need to operate on metabolically healthy obese patients was questioned; however, the reduction of risk parameters and the delayed onset of comorbidities has justified the importance of timely intervention. Recently, the study of cytokine profiles and inflammation markers has also shown that adiposity itself generates long-term deleterious effects, so surgery could fulfill preventive functions in that regard.

Due to the high demand for health care for patients with obesity in our country, as well as the deficiency of useful long-term medical treatments to control obesity, the Obesity and Bariatric Surgery Clinic at this time focuses almost exclusively on the management of patients who meet the criteria and selection protocol for bariatric surgery. Because patients are selected for this surgery according to international criteria, in this study we found patients with extreme degrees of obesity and high cardiometabolic risk; these patients will clearly benefit from interventional management and surgery. Other patients with less obesity or who do not meet criteria for surgery should not be operated on, since instead of helping them, they risk unnecessary malnutrition, poor nutrition, malabsorption, stones, and other adverse effects associated with bariatric surgery, even when this is done by an expert. These patients should continue with medical therapies and nutritional guidance available in other levels of care, and if we consider that this is most patients, multidisciplinary teams should be created in other centers, even if the surgery is not is the objective. Educating patients and staff of health services at all levels, will help prevent and detect patients with obesity earlier, but will also help detect patients with high health risks who are candidates for care by third-level specialists, such as patients with extreme degrees of obesity. The current results of our clinic show the usefulness of these teams at the institutional level.

Conclusions

The patient with extreme obesity who meets the criteria and the necessary protocol to undergo bariatric surgery reduces the EWL% significantly and improves comorbidities in the first year after surgery in a center that has the multidisciplinary management suitable for treating extreme obesity. New equipment, approaches, and research in our country are needed to create specific recommendations for Mexican patients with this diagnosis.

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