Iron Supplementation and Anemia After Sleeve Gastrectomy

Background and Rationale Iron deficiency anemia (IDA) is a prevalent and clinically significant long-term complication following Laparoscopic Sleeve Gastrectomy (LSG), the most commonly performed bariatric procedure worldwide. Despite universal multivitamin supplementation, the incidence of IDA rises steadily post-operatively, impacting patient quality of life, cognitive function, and healthcare utilization. A critical evidence gap exists regarding the efficacy of routine prophylactic oral iron supplementation compared to a strategy of standard multivitamin use with iron monitoring. Current guidelines lack consensus due to insufficient comparative long-term data. This study aims to provide high-level evidence to inform postoperative protocols by directly comparing these two distinct management strategies.

Study Design and Setting This is a prospective, observational, comparative cohort study conducted within the bariatric surgery units of Kasr Al-Ainy Hospital, Cairo University. The study leverages existing, routine clinical practices at two participating units, allowing for a real-world comparison of outcomes. Participants will be managed according to the standard post-operative supplementation protocol of their treating surgical unit; the research protocol does not assign interventions.

Study Cohorts

Eligible participants will be enrolled into one of two cohorts based on the standard care protocol of their surgical unit:

Prophylactic Iron Cohort: Patients whose standard care includes a daily prophylactic dose of 60 mg elemental iron (administered as Ferrodep®, 30 mg capsule every 12 hours) in addition to a daily standard multivitamin.

Standard Multivitamin Cohort: Patients whose standard care includes a daily standard multivitamin only (e.g., Centrum Silver®), which contains approximately 10 mg of iron, with no additional prophylactic iron.

Study Procedures and Assessments Consecutively enrolled patients scheduled for primary LSG will be assessed pre-operatively (baseline) and at 3 and 6 months post-operatively. Data collection will include standardized laboratory panels (hemoglobin, ferritin, iron studies, complete blood count indices), documentation of supplementation adherence, and patient-reported outcome measures. All primary and secondary outcome measures are pre-specified and listed in the designated module.

Statistical Considerations The primary outcome is the cumulative incidence of IDA at 6 months post-surgery, with IDA defined per protocol-specific laboratory criteria. Secondary outcomes include longitudinal changes in hematological parameters, adherence rates, and patient-reported fatigue. A sample size of 66 participants (33 per cohort) was calculated to provide 85% power to detect a significant difference in the primary outcome. Data will be analyzed using SPSS software with appropriate statistical tests for between-group comparisons, as detailed in the statistical analysis plan.

Inclusion criteria

• Adults aged 18 to 65 years scheduled to undergo primary laparoscopic sleeve gastrectomy (LSG).
• Capable of understanding and providing written informed consent for participation.
• Able and willing to commit to the 6-month post-operative follow-up schedule at the bariatric clinic.

Exclusion criteria

• Prior history of major gastrointestinal surgery (e.g., bowel resection, gastrectomy) that could independently affect iron absorption.
• Pre-existing malabsorptive conditions (e.g., inflammatory bowel disease, celiac disease).
• Diagnosis of other known forms of anemia (e.g., thalassemia, vitamin B12/folate deficiency, anemia of chronic disease) that would confound the diagnosis of iron deficiency anemia (IDA).
• Any condition that, in the investigator's judgment, would interfere with full participation in the study or pose a significant risk.