Longitudinal assessment of the quality of life of patients after gastric bypass CURRENT STATUS: POSTED

Bariatric surgery is currently considered an effective way to lose weight after failure in the clinical treatment over a 2-year period. Severe obesity is associated with a wide range of serious health complications and reduced health-related quality of life and throughout its context has a significant impact on the health, longevity and quality of life of individuals. The objective of this study was to monitor the impact of weight reduction, induced by bariatric gastric bypass surgery, on the quality of life of pre and post-operative patients at 1, 2 and 6 months. Methods Longitudinal observational study conducted from December 2016 to October 2017 in southern Brazil. The convenience sample consisted of 104 obese individuals eligible to undergo bariatric gastric bypass surgery. The quality of life evaluation was performed using the SF-36 self-administered questionnaire (The Medical Outcomes Study Short Form Health Survey).


Results
Obese patients presented significant weight loss after surgery and in the evaluation of quality of life the mean scores of the 8 domains of the SF-36 obtained a significant improvement (p <0.001) between time 0 and 6, as well as the components of mental health (vitality, social aspects, emotional aspects and mental health) and physical health component (functional capacity, physical aspects, pain and general state of health).

Conclusions
Patients who underwent gastric bypass bariatric surgery had significant improvements in quality of life during the 6 postoperative months.

Background
Bariatric surgery is currently considered an effective way for sustainable weight loss, improving comorbidities associated with obesity, health and well-being of patients [4], especially when the conservative treatment fails [5].
Since the 1990s, bariatric surgical procedures have become increasingly common as a surgical option 3 to deal with morbid obesity. In this context, the gastric bypass has been considered the gold standard with its established long-term results. However, the vertical gastrectomy procedure is rapidly overtaking the gastric bypass because of its simplicity and rapid initial weight loss [6].
The World Health Organization points to obesity as one of the greatest public health problems in the world. According to data from VIGITEL 2016 (Surveillance of Risk Factors and Protection for Chronic Diseases by Telephone Inquiry) [8] the prevalence of obesity in Brazil (BMI ≥ 30.0 kg/m²) increased from 2006 (11.8%) to 2016 (18.9%), and the projection is that by 2025, about 2.3 billion adults will be overweight and over 700 million will be obese [7].
According to the latest research by the Brazilian Society of Bariatric and Metabolic Surgery (BSBMS), 105,642 thousand surgeries were performed in 2017 in the country, or 5.6% more than in 2016, when 100,000 people underwent the procedure in the private sector. Brazil is considered the second country in the world in number of bariatric surgeries performed and women represent 76% of patients [21].
In order to evaluate the success of the surgical treatment, periodic follow-up after bariatric surgery is Data collection was performed after consultations with a multidisciplinary team in the pre-and postoperative periods at 1, 2 and 6 months, and the research is in continuity.

The quality of life evaluation was performed through the completion of the SF-36 (The Medical
Outcomes Study Short Form Health Survey), translated and validated in Brazil by Ciconelli et al., 1999 [9].
The anthropometric data of the patients (weight, height, BMI), were obtained by analyzing their medical records, as well as the characteristics of the sample (age, gender and physical activity selfreported, and comorbidities through exams and clinical evaluation).
BMI was assessed according to the World Health Organization International Classification of obesity, which divides adiposity into grades or classes [3]. Overweight was calculated preoperatively, using the following formula: current weight -ideal weight (BMI 25 kg/m²) = overweight.
The percentage of excess weight loss (%EWL) was calculated using the formula: preoperative weightcurrent weight x 100 / preoperative weight -ideal weight. The SF-36 quality of life assessment instrument was created with the purpose of being a generic health assessment questionnaire, easy to administer and understand. It is a multidimensional questionnaire consisting of 36 items, distributed in 8 domains: functional capacity (10 items), physical aspects (4 items), pain (2 items), general health status (5 items), vitality (4 items), social aspects (2 items), emotional aspects (3 items), mental health (5 items) and a comparative evaluation question between the current health conditions and that of a year ago. It assesses both the negative aspects of health (illness or disease) and the positive aspects (well-being) [9].
The score is calculated and the final score is obtained through a raw scale (0-100), the closer to 100,

Results
A total of 104 patients, with a mean age of 38.59 (± 9.98) years, the majority of them female (81.7%), self-declared white skin color (97.1%), and with associated comorbidities (98.1%). Among the most common comorbidities, depression was the most prevalent, present in 62.5% of the patients. The other characteristics of the sample in the preoperative period can be seen in Table 1.
In the preoperative period, the mean BMI of the individuals was 42.31 kg/m², of these, 75% of the sample classified as grade III obesity. After 6 months, a significant change in the classification was observed, and half of the individuals (50%) were classified as overweight, out of the obesity range.
The classification of the nutritional status of the patients in the 4 times of evaluation according to the BMI can be seen in Table 2.
In the evaluation of the quality of life, the mean score of the 8 domains of SF-36 obtained a significant improvement (p < 0.001) between time 0 and 6, as well as mental health components (vitality, social 6 aspects, emotional aspects and mental health) and physical health component (functional capacity, physical aspects, pain and general state of health) that combine the related domains. These results can be seen in table 3.  Table 4.

Discussion
This study described the impact of weight reduction on the quality of life of patients submitted to gastric bypass surgery during the 6 months postoperatively, the findings showed that there was a significant improvement in quality of life after bariatric surgery.
The quality of life after surgery is proportional to the amount of weight lost. Being the percentage of excess weight loss greater than 50% within one year after surgery one of the main success criteria for bariatric surgery [11].
In the present study, the mean values of the %EWL of patients was 50.19%, period referring to a significant improvement in the quality of life of the patients studied. In a retrospective study conducted by Silva et al [12], 82 patients underwent bariatric surgery and obtained a mean of %EWL of 51.25% in the postoperative period of 6 months, corroborating with the results found.
Regarding quality of life, the scores of the 8 domains obtained a significant improvement when compared between time 0 (preoperative) and 6 (postoperative). Versteegden et al [13]  The SF-36 has been used in several studies to evaluate generic measures in research on obesity, mainly because this instrument is easy to understand, brief and consistent [14,15,16,17,18,19].

Ethics approval and consent to participate
This study was approved by the research ethics committee of the Franciscan University, nº 1.830.670.
All individuals invited to participate signed the Free and Informed Consent Term after receiving clarification about research.

Consent for publication
Not applicable.

Availability of data and materials
The datasets used and/or analysed during the current study are available from the corresponding author on reasonable request. Tables.pdf