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Active, Not Recruiting

NCT Number: NCT07348822

8-Year Outcomes After Sleeve Gastrectomy

Obesity is a major global public health concern, and bariatric surgery is recognized as the most effective treatment for achieving sustained weight loss and improving obesity-related comorbidities. Sleeve gastrectomy (SG) is one of the most commonly performed bariatric procedures; however, long-term outcomes vary considerably among individuals. While some patients maintain satisfactory weight loss, others experience suboptimal weight loss or weight regain several years after surgery. Evidence suggests that long-term weight trajectories after SG may be influenced by metabolic changes, dietary habits, and lifestyle factors, highlighting the need for extended follow-up studies.

This observational cohort study aims to evaluate the long-term outcomes of individuals who underwent sleeve gastrectomy approximately 8 years ago. Anthropometric measurements, biochemical parameters, and nutritional status will be reassessed at an 8-year follow-up visit and compared with data obtained during the preoperative period and at postoperative 6 months. By examining within-subject changes over time, this study seeks to provide insight into the long-term sustainability of weight loss after sleeve gastrectomy and to identify metabolic and nutritional factors associated with long-term outcomes.

Active, Not Recruiting

This study is active but is not currently recruiting participants.

Key information

Conditions

Sleeve Gastrectomy Body Weight Nutrition Disorders Nutritional and Metabolic Diseases Obesity Obesity & Overweight Overnutrition Overweight Pathological Conditions, Signs and Symptoms Signs and Symptoms

Age range

18 year–65 year

Sex eligibility

All sexes

Study type

Observational

Primary location

Mudanya Univesity

Bursa, Mudanya, Turkey (Türkiye)

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Adults aged 18-65 years
  • Patients who underwent sleeve gastrectomy approximately 8 years prior to study enrollment
  • Patients with available postoperative follow-up data at 6 months, including anthropometric measurements, biochemical parameters, and nutritional status assessments
  • Patients willing to participate in long-term follow-up and attend in-person evaluations

Exclusion criteria

  • Pregnancy or lactation
  • Presence of acute illness or active infection at the time of evaluation
  • Presence of acute illness, infection, or comorbid conditions that may limit study safety or validity, including malignancy, type 1 diabetes mellitus, renal or hepatic failure, recent stroke or myocardial infarction, nephrolithiasis, drug or alcohol abuse, eating disorders, severe depression or other major psychiatric disorders, inflammatory bowel disease, cardiac arrhythmias or heart failure, respiratory failure, or chronic systemic corticosteroid therapy.
  • Professional athletes

Treatment and study plan

Primary outcomes

  1. Change in Fat Mass

    Time frame: Preoperative, postoperative 6 months, and postoperative 8 years

    Changes in fat mass measured using multi-frequency bioelectrical impedance analysis (BIA).

  2. Change in Body Weight

    Time frame: Preoperative, postoperative 6 months, and postoperative 8 years

    Body weight measured using a calibrated digital scale with participants wearing light clothing and no shoes.

  3. Change in Body Mass Index (BMI)

    Time frame: Preoperative, postoperative 6 months, and postoperative 8 years

    BMI calculated as weight in kilograms divided by height in meters squared (kg/m²), measured using a wall-mounted stadiometer.

  4. Change in Waist Circumference

    Time frame: Preoperative, postoperative 6 months, and postoperative 8 years

    Waist circumference measured in centimeters at the midpoint between the subcostal margin and the iliac crest with participants standing upright.

  5. Change in Hip Circumference

    Time frame: Preoperative, postoperative 6 months, and postoperative 8 years

    Hip circumference measured in centimeters at the level of maximum gluteal protrusion.

  6. Percent Total Weight Loss (TWL%)

    Time frame: Postoperative 6 months and postoperative 8 years

    Calculated as [(preoperative weight - postoperative weight) / preoperative weight] × 100.

  7. Percent Excess Weight Loss (EWL%)

    Time frame: Postoperative 6 months and postoperative 8 years

    Calculated as [(preoperative weight - postoperative weight) / (preoperative weight - ideal body weight)] × 100, where ideal body weight corresponds to a BMI of 25 kg/m².

  8. Change in Body Fat Percentage

    Time frame: Preoperative baseline, postoperative 6 months, and postoperative 8 years

    Changes in body fat percentage measured using multi-frequency bioelectrical impedance analysis (BIA).

  9. Change in Skeletal Muscle Mass

    Time frame: Preoperative baseline, postoperative 6 months, and postoperative 8 years

    Changes in skeletal muscle mass measured using multi-frequency bioelectrical impedance analysis (BIA).

Secondary outcomes

  1. Change in Fasting Plasma Glucose

    Time frame: Preoperative, postoperative 6 months, and postoperative 8 years

    Fasting plasma glucose measured after at least 8 hours of fasting using venous blood samples.

  2. Change in Fasting Insulin Levels

    Time frame: Preoperative, postoperative 6 months, and postoperative 8 years

    Fasting insulin levels measured from venous blood samples obtained after at least 8 hours of fasting.

  3. Change in Glycated Hemoglobin (HbA1c)

    Time frame: Preoperative, postoperative 6 months, and postoperative 8 years

    HbA1c levels measured to assess long-term glycemic control.

  4. Change in Lipid Profile Parameters

    Time frame: Preoperative, postoperative 6 months, and postoperative 8 years

    Serum lipid parameters including total cholesterol, LDL cholesterol, HDL cholesterol, and triglycerides measured after an overnight fast.

  5. Change in Liver Enzyme Levels

    Time frame: Preoperative, postoperative 6 months, and postoperative 8 years

    Serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels measured from fasting blood samples.

  6. Change in Renal and Metabolic Biomarkers

    Time frame: Preoperative, postoperative 6 months, and postoperative 8 years

    Serum urea and uric acid levels measured to assess renal and metabolic function.

  7. Change in Serum Albumin

    Time frame: Preoperative, postoperative 6 months, and postoperative 8 years

    Changes in serum albumin levels measured from venous blood samples.

  8. Change in Micronutrient Levels

    Time frame: Preoperative, postoperative 6 months, and postoperative 8 years

    Serum levels of vitamin B12, folic acid, magnesium, total calcium, sodium, and potassium measured to assess micronutrient status.

  9. Change in Physical Activity Level

    Time frame: Preoperative, postoperative 6 months, and postoperative 8 years

    Physical activity levels assessed using the International Physical Activity Questionnaire (IPAQ).

  10. Change in Fat-Free Mass

    Time frame: Preoperative baseline, postoperative 6 months, and postoperative 8 years

    Changes in fat-free mass measured using multi-frequency bioelectrical impedance analysis (BIA).

  11. Change in Total Protein

    Time frame: Preoperative baseline, postoperative 6 months, and postoperative 8 years

    Changes in total serum protein levels measured from venous blood samples.

  12. Change in Hemoglobin

    Time frame: Preoperative baseline, postoperative 6 months, and postoperative 8 years

    Changes in hemoglobin levels measured from venous blood samples.

  13. Change in Hematocrit

    Time frame: Preoperative baseline, postoperative 6 months, and postoperative 8 years

    Changes in hematocrit levels measured from venous blood samples.

  14. Change in Serum Ferritin

    Time frame: Preoperative baseline, postoperative 6 months, and postoperative 8 years

    Changes in serum ferritin levels measured from venous blood samples.

  15. Change in Serum Iron

    Time frame: Preoperative baseline, postoperative 6 months, and postoperative 8 years

    Changes in serum iron levels measured from venous blood samples.

Sponsors and collaborators

Lead sponsor

Medipol University

Other

Registry information

Official study title

8-Year Outcomes After Sleeve Gastrectomy: Anthropometric, Biochemical, and Nutritional Evaluation

Important dates

Study start
2025
Primary completion
2026
Study completion
2026
First posted
Jan 16, 2026
Registry last updated
Feb 3, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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