# Bariatric surgery: pre-operative comorbidities, postoperative results, and complications: a single-center retrospective cohort analysis

## TL;DR

Bariatric surgery significantly reduces weight and metabolic conditions like diabetes and hypertension within six months, but comes with high rates of complications like nutritional deficiencies.

## Contribution

This study provides a detailed analysis of short-term outcomes and complications of bariatric surgery in Brazil, emphasizing the need for postoperative monitoring.

## Key findings

- Bariatric surgery led to significant remission of hypertension (55%), Type 2 diabetes (64%), and dyslipidemia (64%) within 6 months.
- Patients experienced an average weight loss of 32.5 kg and a BMI decrease of 12.1 kg/m², with no difference between surgical techniques.
- Over 70% of patients experienced postoperative complications, primarily nutritional deficiencies and dumping syndrome.

## Abstract

Bariatric surgery is the most effective treatment for weight loss and also promotes remission of preoperative metabolic comorbidities.

The aim of this study was to analyze preoperative comorbidities, evaluate postoperative outcomes, and assess complications 6 months after bariatric surgery in a hospital in the state of Santa Catarina, Brazil.

A retrospective cohort study was conducted with patients who underwent bariatric surgery between 2021 and 2022 and were followed up for a period of 6 months after the procedure.

There was a predominance of female patients (81.6%), with a mean age of 38.7 years. The preoperative prevalence of hypertension, Type 2 diabetes, dyslipidemia, and hepatic steatosis was 36.7, 22.4, 22.4, and 32.7%, respectively. The postoperative remission rates for these conditions were 55, 64, 70, and 69%, respectively. Except for diabetes, no significant differences were found between the Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG) groups. There was a significant reduction in weight (p<0.01) and body mass index (BMI) (p<0.01), with no statistical differences between the RYGB and SG groups. Postoperative complications occurred in 73.5% of patients, including anemia, vitamin deficiencies, cholelithiasis, dumping syndrome, anastomotic ulcer, chronic diarrhea, and anastomotic stricture.

The study described the preoperative comorbidity profile, postoperative outcomes, and complications with findings consistent with existing literature, except for underreporting dyslipidemia and hepatic steatosis. No statistical difference was observed between the surgical techniques performed.

Bariatric surgery led to significant remission of metabolic comorbidities such as hypertension (55%), Type 2 diabetes (64%), and dyslipidemia (64%) within 6 months after the procedure.

There was significant weight loss among operated patients, with an average reduction of 32.5 kg and a body mass index (BMI) decrease of 12.1 kg/m2, regardless of the surgical technique used (Roux-en-Y gastric bypass [RYGB] or sleeve gastrectomy [SG]).

More than 70% of the patients experienced some postoperative complications, most frequently nutritional deficiencies (iron, vitamin D, and B12) and dumping syndrome, with similar rates across surgical techniques.

The study reinforces the short-term effectiveness of bariatric surgery but highlights the need for strict postoperative follow-up due to the high prevalence of adverse effects and the potential underdiagnosis of preexisting comorbidities.

Bariatric surgery, whether through Roux-en-Y gastric bypass (RYGB) or vertical sleeve gastrectomy (SG), is associated with significant short-term weight loss and remission of metabolic comorbidities in patients with morbid obesity. This retrospective cohort study conducted in southern Brazil reinforces the effectiveness of both surgical techniques and highlights the importance of structured postoperative monitoring due to the high frequency of nutritional deficiencies and other complications, even in the early months following surgery.

Clinical Implication: Both Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG) resulted in substantial weight loss and remission of comorbidities such as hypertension, Type 2 diabetes, dyslipidemia, and hepatic steatosis within 6 months, with no statistically significant differences between techniques, apart from the selective allocation of diabetic patients to the RYGB group. Public Health Relevance: In the context of the rising obesity burden in Brazil and worldwide, bariatric surgery remains a critical intervention not only for weight reduction but also for improving metabolic health, with direct implications for reducing long-term morbidity and healthcare costs. Future Research: Longer follow-up studies with prospective designs and comprehensive data collection are needed to assess long-term outcomes and late complications and to better differentiate the efficacy of surgical techniques beyond selection biases.