The ABCG8 polymorphism increases the risk of gallbladder cancer in the general population and gallstones in obese patients from Poland.

BACKGROUND: Gallstone disease (GD) is common but remains asymptomatic in most cases. However, gallstones can lead to complications like choledocholithiasis or gallbladder cancer. In this study, we analyse the common genetic risk factor for GD, the p.D19H variant in the sterol transporter ABCG8, in Polish patients with gallstones and gallbladder cancer. METHODS: Three adult cohorts were prospectively recruited: 65 patients with gallbladder cancer, 170 obese individuals scheduled for bariatric surgery and 72 patients who underwent endoscopic retrograde cholangiopancreatography due to recurrent choledocholithiasis. The control cohort consisted of 172 gallstone-free adults. The ABCG8 p.D19H (rs11887534) polymorphism was genotyped using TaqMan assays. RESULTS: The minor allele frequency (MAF) of the ABCG8 p.D19H polymorphism was significantly (p = .02) higher among cases with either gallstones or gallbladder cancer (MAF = 8.4%) as compared to controls (MAF = 4.0%). The highest frequency of the risk allele was detected in patients with gallbladder cancer (18.5%) and obese patients with GD (17.5%), followed by individuals with choledocholithiasis (13.9%). Notably, the p.19H variant was associated with an increased risk of developing gallbladder cancer (OR 2.76, 95% CI 1.16-6.54, p = .01) and an increased risk of GD in obese individuals scheduled for bariatric surgery (OR = 2.70, 95% CI 1.05-6.49, p = .03), but did not significantly affect the risk of choledocholithiasis. CONCLUSIONS: The ABCG8 p.D19H common risk variant increases the risk of developing gallbladder cancer in Central Europeans and enhances the risk of gallstones in the obese. Carriers of the p.D19H variant might benefit from personalized preventive strategies, particularly regarding gallbladder cancer.

Oxidative stress in metabolic dysfunction-associated steatotic liver disease (MASLD): How does the animal model resemble human disease?

Despite decades of research, the pathogenesis of metabolic dysfunction-associated steatotic liver disease (MASLD) is still not completely understood. Based on the evidence from preclinical models, one of the factors proposed as a main driver of disease development is oxidative stress. This study aimed to search for the resemblance between the profiles of oxidative stress and antioxidant defense in the animal model of MASLD and the group of MASLD patients. C57BL/6J mice were fed with the Western diet for up to 24 weeks and served as the animal model of MASLD. The antioxidant profile of mice hepatic tissue was determined by liquid chromatography-MS3 spectrometry (LC-MS/MS). The human cohort consisted of 20 patients, who underwent bariatric surgery, and 6 controls. Based on histological analysis, 4 bariatric patients did not have liver steatosis and as such were also classified as controls. Total antioxidant activity was measured in sera and liver biopsy samples. The hepatic levels of antioxidant enzymes and oxidative damage were determined by Western Blot. The levels of antioxidant enzymes were significantly altered in the hepatic tissue of mice with MASLD. In contrast, there were no significant changes in the antioxidant profile of hepatic tissue of MASLD patients, except for the decreased level of carbonylated proteins. Decreased protein carbonylation together with significant correlations between the thioredoxin system and parameters describing metabolic health suggest alterations in the thiol-redox signaling. Altogether, these data show that even though the phenotype of mice closely resembles human MASLD, the animal-to-human translation of cellular and molecular processes such as oxidative stress may be more challenging.

Early adoption of laparoscopic liver surgery in Poland: a national retrospective cohort study.

BACKGROUND: The need for safe and efficient dissemination of minimally invasive approach in liver surgery is among the current challenges for hepatobiliary surgeons. After the stage of innovators and pioneers, the following countries should adopt a laparoscopic approach. The aim of this study was to assess the national experience and trend in implementing laparoscopic liver resection (LLR) in Poland. MATERIALS AND METHODS: A national registry of LLR performed in Poland was established in June 2020. All LLR cases performed before were included retrospectively, followed by prospectively collected new cases. Baseline characteristics, preoperative and intraoperative data, short-term results and long-term follow-up were recorded. RESULTS: Since 2010 up to the end of 2022 there were 718 LLRs performed in Poland. The national rate of laparoscopic approach has gradually increased since 2017 ( P <0.001), reaching the rate of 11.7% in 2022. There were 443 (61.7%), 107 (14.9%), and 168 (23.4%) LLRs performed in accordance to increasing grades of difficulty. The move towards more demanding cases had an increasing trend over the years ( P <0.001). Total intraoperative adverse event and postoperative severe complications rates were estimated for 13.5% ( n =97) and 6.7% ( n =48), respectively. 30-day reoperation, readmission and postoperative mortality rates were 3.6% ( n =26), 2.8% ( n =20), and 0.8% ( n =6), respectively. While the R0 resection margin was assessed in 643 (89.6%) cases, the total textbook outcomes (TO) were achieved in 525 (74.5%) cases. Overcoming the learning curve of 60 LLRs, resulted in an increasing TO rate from 72.3 to 80.6% ( P =0.024). CONCLUSIONS: It is the first national analysis of a laparoscopic approach in liver surgery in Poland. An increasing trend of minimizing invasiveness in liver resection has been observed. Responsible selection of cases in accordance with difficulty may provide results within global benchmark values and textbook outcomes already during the learning curve.

Left Ventricular Morphology and Function in Normotensive, Metabolically Healthy Obese Individuals without Fatty Liver Disease.

BACKGROUND: Obesity is one of the major risk factors for the development of heart failure (HF), although the exact underlying mechanism remains unclear. In the clinical setting, assessing the impact of obesity on the cardiovascular system is difficult due to comorbidities. OBJECTIVES: The purpose of this study was to evaluate an independent influence of obesity on the left ventricular (LV) morphology and function. To eliminate hemodynamic and metabolic confounders, we performed an echocardiographic evaluation of severely obese but normotensive and metabolically healthy patients without fatty liver disease. METHODS: The patients were retrospectively selected from the cohort of 180 consecutive obese patients systematically evaluated with transthoracic echocardiography before bariatric surgery. Finally, 25 obese subjects, predominantly females, were evaluated with transthoracic echocardiography. Inclusion criteria were defined as absence of diabetes, hypertension, and hyperlipidemia, no use of medications and no hepatic steatosis on liver biopsy. They were matched with a control group of healthy subjects with normal body mass index. RESULTS: In obese patients, LV hypertrophy (LVH) (expressed as LV mass indexed for height in meters2.7) was significantly more frequent in the obese group (48 vs. 0%, p < 0.001). LV longitudinal systolic function measured by mitral annular systolic velocity was significantly lower in the obese group (S' 8.5 vs. 9.7 cm/s, p = 0.002). All studied indices of the LV diastolic function (E/A, mean E' and E/E' ratio) were impaired in obese subjects, even after adjustment for systolic blood pressure and heart rate (E/A 1.31 vs. 1.64, p < 0.001, E' mean 11 vs. 14.8 cm/s, p < 0.001, E/E' 7.5 vs. 6.4, p = 0.002 for obese vs. controls, respectively). CONCLUSIONS: LVH is significantly more common, and LV diastolic and longitudinal systolic function is significantly impaired in young, metabolically healthy, normotensive, severely obese individuals without fatty liver disease when compared to age and sex-matched lean subjects. These abnormalities may represent the independent effect of the obesity on the heart, which may contribute to the development the obesity-related HF in later life.

Stapled Anastomosis for Side-to-Side Cavo-Cavostomy in Orthotopic Liver Transplantation.

In liver transplantation, a side-to-side anastomosis is one of the commonly performed techniques of the inferior vena cava reconstruction. The authors report a case of an application of an endoscopic vascular linear stapler for a side-to-side caval anastomosis during deceased-donor liver transplantation. The back table procedure was performed in a standard fashion for a side-to-side anastomosis. The linear vascular stapler was introduced during the temporary clamping of the recipient's inferior vena cava and the anastomosis was created without problems. Suturing of the resulting defect completed the anastomosis. The use of the stapler resulted in a shortening of the anastomosis time. The staple line after the reperfusion of the graft was completely sealed. The patient's postoperative course was uncomplicated and post-operative ultrasound and computed tomography confirmed the patency of the anastomosis. This case demonstrates a novel approach to a side-to-side caval reconstruction during liver transplantation that enables a shortening of the implantation time and may improve the quality of anastomoses.

Mixed epithelial and stromal tumor of the kidney: A case report.

Mixed epithelial and stromal tumor (MEST) is a rare neoplasm of the kidney, affecting mostly women at menopausal age. While few cases of malignant transformation have been described in the literature, MEST is usually considered a benign tumor with minimal risk of local recurrence or distance metastases. The current study presents a case of a 18-year old male patient with a cystic tumor of the left kidney incidentally diagnosed on magnetic resonance imaging of the heart performed for other reasons. The patient underwent a partial nephrectomy, with perioperative course being uneventful. The pathology report revealed MEST of the kidney. No local recurrence nor disease progression have been observed in the patient during the one-year follow-up period. The present case report is evidence that may help in developing guidelines on the management of patients with benign renal masses.

Ultrasound- and biomarker-based assessment of hepatic steatosis in patients with severe obesity.

INTRODUCTION: Nonalcoholic fatty liver disease (NAFLD) is a common liver abnormality, but its noninvasive diagnosis in patients with severe obesity remains difficult. OBJECTIVES: Our aim was to investigate the usefulness of the ultrasound­based hepatorenal index (HRI) technique and 2 biomarker­based methods, including the hepatic steatosis index (HSI) and NAFLD logit score for the diagnosis of NAFLD in patients referred for bariatric surgery. PATIENTS AND METHODS: A total of 162 patients, including 106 with NAFLD, admitted for bariatric surgery participated in the study. Fat fraction level and the presence of NAFLD were determined using surgical liver biopsy. Each patient underwent liver ultrasound examination and blood tests to determine the HRI, HSI, and NAFLD logit score. RESULTS: For the NAFLD diagnosis, the HRI, HSI, and NAFLD logit score techniques achieved areas under the receiver operating characteristic curves of 0.879, 0.577, and 0.825, respectively. The Spearman correlation coefficients between the liver fat fraction values and the HRI, HSI, and NAFLD logit score were equal to 0.695, 0.215, and 0.595, respectively. The optimal cutoff values for the NAFLD diagnosis for the HRI, HSI, and NAFLD logit score were equal to 1.12, 56.1, and 0.59, respectively, and significantly differed from the cutoff values reported for the general population in the literature. CONCLUSIONS: Our study confirmed the usefulness of only 2 out of 3 techniques, the HRI and the NAFLD logit score for the diagnosis of NAFLD in patients with severe obesity. The methods designed for the general population require different cutoff values to achieve accurate performance in patients with severe obesity.

MTARC1 and HSD17B13 Variants Have Protective Effects on Non-Alcoholic Fatty Liver Disease in Patients Undergoing Bariatric Surgery.

The severity of hepatic steatosis is modulated by genetic variants, such as patatin-like phospholipase domain containing 3 (PNPLA3) rs738409, transmembrane 6 superfamily member 2 (TM6SF2) rs58542926, and membrane-bound O-acyltransferase domain containing 7 (MBOAT7) rs641738. Recently, mitochondrial amidoxime reducing component 1 (MTARC1) rs2642438 and hydroxysteroid 17-beta dehydrogenase 13 (HSD17B13) rs72613567 polymorphisms were shown to have protective effects on liver diseases. Here, we evaluate these variants in patients undergoing bariatric surgery. A total of 165 patients who underwent laparoscopic sleeve gastrectomy and intraoperative liver biopsies and 314 controls were prospectively recruited. Genotyping was performed using TaqMan assays. Overall, 70.3% of operated patients presented with hepatic steatosis. NASH (non-alcoholic steatohepatitis) was detected in 28.5% of patients; none had cirrhosis. The increment of liver fibrosis stage was associated with decreasing frequency of the MTARC1 minor allele (p = 0.03). In multivariate analysis MTARC1 was an independent protective factor against fibrosis ≥ 1b (OR = 0.52, p = 0.03) and ≥ 1c (OR = 0.51, p = 0.04). The PNPLA3 risk allele was associated with increased hepatic steatosis, fibrosis, and NASH (OR = 2.22, p = 0.04). The HSD17B13 polymorphism was protective against liver injury as reflected by lower AST (p = 0.04) and ALT (p = 0.03) activities. The TM6SF2 polymorphism was associated with increased ALT (p = 0.04). In conclusion, hepatic steatosis is common among patients scheduled for bariatric surgery, but the MTARC1 and HSD17B13 polymorphisms lower liver injury in these individuals.

Mitochondria, oxidative stress and nonalcoholic fatty liver disease: A complex relationship.

According to the 'multiple-hit' hypothesis, several factors can act simultaneously in nonalcoholic fatty liver disease (NAFLD) progression. Increased nitro-oxidative (nitroso-oxidative) stress may be considered one of the main contributors involved in the development and risk of NAFLD progression to nonalcoholic steatohepatitis (NASH) characterized by inflammation and fibrosis. Moreover, it has been repeatedly postulated that mitochondrial abnormalities are closely related to the development and progression of liver steatosis and NAFLD pathogenesis. However, it is difficult to determine with certainty whether mitochondrial dysfunction or oxidative stress are primary events or a simple consequence of NAFLD development. On the one hand, increasing lipid accumulation in hepatocytes could cause a wide range of effects from mild to severe mitochondrial damage with a negative impact on cell fate. This can start the cascade of events, including an increase of cellular reactive nitrogen species (RNS) and reactive oxygen species (ROS) production that promotes disease progression from simple steatosis to more severe NAFLD stages. On the other hand, progressing mitochondrial bioenergetic catastrophe and oxidative stress manifestation could be considered accompanying events in the vast spectrum of abnormalities observed during the transition from NAFL to NASH and cirrhosis. This review updates our current understanding of NAFLD pathogenesis and clarifies whether mitochondrial dysfunction and ROS/RNS are culprits or bystanders of NAFLD progression.

The impact of severe postoperative complications on outcomes of bariatric surgery-multicenter case-matched study.

BACKGROUND: Bariatric surgery has relatively low complication rates, especially severe postoperative complications (defined by Clavien-Dindo classification as types 3 and 4), but these rates cannot be ignored. In other than bariatric surgical disciplines, complications affect not only short-term but also long-term results. In the field of bariatric surgery, this topic has not been extensively studied. OBJECTIVES: The aim of the study was to assess the outcomes of bariatric treatment in patients with obesity and severe postoperative complications in comparison to patients with a noneventful perioperative course. SETTING: Six surgical units at Polish public hospitals. METHODS: We performed a multicenter propensity score matched analysis of 206 patients from 6 Polish surgical units and assessed the outcomes of bariatric procedures. A total of 103 patients with severe postoperative complications (70 laparoscopic sleeve gastrectomy [SG] and 33 with laparoscopic Roux en Y gastric bypass [RYGB]) were compared to 103 patients with no severe complications in terms of peri- and postoperative outcomes. RESULTS: The outcomes of bariatric treatment did not differ between compared groups. Median percentage of total weight loss 12 months after the surgery was 28.8% in the group with complications and 27.9% in patients with no severe complications (P = 0.993). Remission rates of both type 2 diabetes mellitus and arterial hypertension showed no significant difference between SG and RYGB (36% versus 42%, P = 0.927, and 41% versus 46%, P = 0.575. respectively). CONCLUSIONS: The study suggests that severe postoperative complications had no significant influence either on weight loss effects or obesity-related diseases remission.

The Influence of Surgical Weight Reduction on Left Atrial Strain.

BACKGROUND: Obesity increases and surgical weight reduction decreases the risk of atrial fibrillation (AF) and heart failure (HF). We hypothesized that surgically induced weight loss may favorably affect left atrial (LA) mechanical function measured by longitudinal strain, which has recently emerged as an independent imaging biomarker of increased AF and HF risk. METHODS: We retrospectively evaluated echocardiograms performed before and 12.2 ± 2.2 months after bariatric surgery in 65 patients with severe obesity (mean age 39 [36; 47] years, 72% of females) with no known cardiac disease or arrhythmia. The LA mechanical function was measured by the longitudinal strain using the semi-automatic speckle tracking method. RESULTS: After surgery, body mass index decreased from 43.72 ± 4.34 to 30.04 ± 4.33 kg/m2. We observed a significant improvement in all components of the LA strain. LA reservoir strain (LASR) and LA conduit strain (LASCD) significantly increased (35.7% vs 38.95%, p = 0.0005 and - 19.6% vs - 24.4%, p < 0.0001) and LA contraction strain (LASCT) significantly decreased (- 16% vs - 14%, p = 0.0075). There was a significant correlation between an increase in LASR and LASCD and the improvement in parameters of left ventricular diastolic and longitudinal systolic function (increase in E' and MAPSE). Another significant correlation was identified between the decrease in LASCT and an improvement in LA function (decrease in A'). CONCLUSIONS: The left atrial mechanical function improves after bariatric surgery. It is partially explained by the beneficial effect of weight reduction on the left ventricular diastolic and longitudinal systolic function. This effect may contribute to decreased risk of AF and HF after bariatric surgery.

Skin autofluorescence as a novel predictor of acute kidney injury after liver resection.

BACKGROUND: Skin autofluorescence (SAF) reflects accumulation of advanced glycation end-products (AGEs). The aim of this study was to evaluate predictive usefulness of SAF measurement in prediction of acute kidney injury (AKI) after liver resection. METHODS: This prospective observational study included 130 patients undergoing liver resection. The primary outcome measure was AKI. SAF was measured preoperatively and expressed in arbitrary units (AU). RESULTS: AKI was observed in 32 of 130 patients (24.6%). SAF independently predicted AKI (p = 0.047), along with extent of resection (p = 0.019) and operative time (p = 0.046). Optimal cut-off for SAF in prediction of AKI was 2.7 AU (area under the curve [AUC] 0.611), with AKI rates of 38.7% and 20.2% in patients with high and low SAF, respectively (p = 0.037). Score based on 3 independent predictors (SAF, extent of resection, and operative time) well stratified the risk of AKI (AUC 0.756), with positive and negative predictive values of 59.3% and 84.0%, respectively. In particular, SAF predicted AKI in patients undergoing major and prolonged resections (p = 0.010, AUC 0.733) with positive and negative predictive values of 81.8%, and 62.5%, respectively. CONCLUSIONS: AGEs accumulation negatively affects renal function in patients undergoing liver resection. SAF measurement may be used to predict AKI after liver resection, particularly in high-risk patients.

Cardiac Morphology, Function, and Hemodynamics in Patients With Morbid Obesity and Nonalcoholic Steatohepatitis.

Background The patients with nonalcoholic fatty liver disease demonstrate an increased cardiovascular risk. The adverse influence of liver abnormalities on cardiac function are among many postulated mechanisms behind this association. The aim of the study was to evaluate cardiac morphology and function in patients with morbid obesity referred for bariatric surgery with liver biopsy. Methods and Results We evaluated with echocardiography 171 consecutive patients without known cardiac disease (median age 42 [interquartile range, 37-48] years, median body mass index 43.7 [interquartile range, 41.0-47.5], 67% female patients. Based on the liver biopsy results, there were 44 patients with nonalcoholic steatohepatitis (NASH), 69 patients with isolated steatosis, and 58 patients without steatosis. Patients with NASH demonstrated signs of left ventricular concentric remodeling and hyperdynamic circulation, including indexed left ventricular end-diastolic diameter [cm/m2]: NASH 1.87 [0.22]; isolated steatosis 2.03 [0.33]; without steatosis 2.01 [0.19], P=0.001; relative wall thickness: NASH 0.49±0.05, isolated steatosis 0.47±0.06, without steatosis 0.46±0.06, P=0.011; cardiac index [L/m2]: NASH 3.05±0.54, isolated steatosis 2.80±0.44, without steatosis 2.79±0.50, P=0.013. After adjustment for sex, age, blood pressure, and heart rate, most of the measures of the left ventricular systolic and diastolic function, left atrial size, right ventricular function, and right ventricular size did not differ between groups. Conclusions In a group of patients with extreme obesity, NASH was associated with left ventricular concentric remodeling and hyperdynamic circulation. Increased cardiac output in NASH may represent an additional risk factor for incident cardiovascular events in this population.

Type 2 Diabetes Remission 5 Years After Laparoscopic Sleeve Gastrectomy: Multicenter Cohort Study.

PURPOSE: Bariatric surgery is no longer considered only as a weight loss surgery but also a way of treating obesity-related comorbidities such as type 2 diabetes mellitus (T2DM). Short-term T2DM remissions in patients undergoing laparoscopic sleeve gastrectomy (LSG) have been shown, but there are very few reports on the mid-term results. We aimed to assess the remission rate of T2DM in obese patients after LSG throughout 5-year follow-up. MATERIALS AND METHODOLOGY: We performed a retrospective multicenter cohort analysis of 240 patients who underwent LSG. We assessed the remission rate of T2DM 1 year and 5 years after surgery. RESULTS: Forty-six percent of patients achieved T2DM remission 5 years after LSG. The remission group had better weight loss results (median% of total weight loss 5 years after: 30.1% (22.9-37.0) vs 23.0% (13.7-30.2), p < 0.001) and were significantly younger than the no remission group (43 (38-52) vs 52 (44-58) years, p < 0.001). Duration of T2DM was significantly shorter (2 (1-5) vs 5 (3-10) years, p < 0.001) with less insulin requirement and less diabetes-related complications (7.2% vs 19.8%, p < 0.001) and significantly lower median DiaRem score (4.0 (IQR 2.0-6.0) vs 12.0 (IQR 5.0-16.0), p < 0.001). Preoperative body mass index (BMI) had no effect on remission. CONCLUSIONS: Our study suggests that diabetes remission after laparoscopic sleeve gastrectomy occurs frequently, and in the 5-year follow-up, it may remain at the level of 46%. We identified the age of patients, duration, and severity of T2DM as factors affecting mid-term diabetes remission. Nevertheless, further well-designed trials are needed to support our findings.

Fat and Sugar-A Dangerous Duet. A Comparative Review on Metabolic Remodeling in Rodent Models of Nonalcoholic Fatty Liver Disease.

Nonalcoholic fatty liver disease (NAFLD) is a common disease in Western society and ranges from steatosis to steatohepatitis to end-stage liver disease such as cirrhosis and hepatocellular carcinoma. The molecular mechanisms that are involved in the progression of steatosis to more severe liver damage in patients are not fully understood. A deeper investigation of NAFLD pathogenesis is possible due to the many different animal models developed recently. In this review, we present a comparative overview of the most common dietary NAFLD rodent models with respect to their metabolic phenotype and morphological manifestation. Moreover, we describe similarities and controversies concerning the effect of NAFLD-inducing diets on mitochondria as well as mitochondria-derived oxidative stress in the progression of NAFLD.

Laparoscopic liver resection for non-colorectal non-neuroendocrine metastases: perioperative and oncologic outcomes.

BACKGROUND: Liver resection is a treatment of choice for colorectal and neuroendocrine liver metastases, and laparoscopy is an accepted approach for surgical treatment of these patients. The role of liver resection for patients with non-colorectal non-neuroendocrine liver metastases (NCNNLM), however, is still disputable. Outcomes of laparoscopic liver resection for this group of patients have not been analyzed. MATERIAL AND METHODS: In this retrospective study, patients who underwent laparoscopic liver resection for NCNNLM at Oslo University Hospital between April 2000 and January 2018 were analyzed. Perioperative and oncologic data of these patients were examined. Postoperative morbidity was classified using the Accordion classification. Kaplan-Meier method was used for survival analysis. Median follow-up was 26 (IQR, 12-41) months. RESULTS: Fifty-one patients were identified from a prospectively collected database. The histology of primary tumors was classified as adenocarcinoma (n = 16), sarcoma (n = 4), squamous cell carcinoma (n = 4), melanoma (n = 16), gastrointestinal stromal tumor (n = 9), and adrenocortical carcinoma (n = 2). The median operative time was 147 (IQR, 95-225) min, while the median blood loss was 200 (IQR, 50-500) ml. Nine (18%) patients experienced postoperative complications. There was no 90-day mortality in this study. Thirty-five (68%) patients developed disease recurrence or progression. Seven (14%) patients underwent repeat surgical procedure for recurrent liver metastases. One-, three-, and five-year overall survival rates were 85%, 52%, and 38%, respectively. The median overall survival was 37 (95%CI, 25 to 49) months. CONCLUSION: Laparoscopic liver resection for NCNNLM results in good outcomes and should be considered in patients selected for surgical treatment.

Nutritional Deficiencies in Patients after Roux-en-Y Gastric Bypass and Sleeve Gastrectomy during 12-Month Follow-Up.

INTRODUCTION: Roux-en-Y gastric bypass (RYGB) and laparoscopic sleeve gastrectomy (LSG) are the two most frequently performed bariatric operations. These two types of metabolic surgery alter the anatomy and function of digestive tract producing significant weight loss in morbidly obese patients but may lead to malnutrition. AIM: Analysis of incidence and severity of malnutrition after bariatric surgery in patients submitted to RYGB or LSG during 12 months of follow-up. MATERIAL AND METHODS: Retrospective study of 98 patients after RYGB (n = 47) or LSG (n = 51) assessed for nutritional deficiencies during 12 months after surgery was conducted. The differences in body mass index (BMI) and blood tests including erythrocytes, haemoglobin, total protein, albumin, iron, ferritin, transferrin, vitamin B12, folic acid, calcium and phosphorus concentrations were compared between groups before the operations and at 1 and 12 months. RESULTS: Nutritional deficiencies were common before surgery with prevalence up to 19.6% for albumin in the LSG group. Median preoperative BMI levels and albumin concentrations were higher in the RYGB group compared to the LSG group, but there was no difference in percent excess weight loss (%EWL) at 1 and 12 months between LSG and RYGB. One month after LSG erythrocyte count, haemoglobin, iron, ferritin and transferrin levels were significantly higher than in the RYGB group. These differences subsided at 12 months. At 12 months, only the prevalence of vitamin B12 deficiency was significantly higher in the RYGB group. CONCLUSION: Both RYGB and LSG lead to nutritional deficiencies despite different properties of operations and similar %EWL during follow-up.