An observational study in Obesity, Morbid, Weight Regain After Bariatric Surgery and Insufficient Weight Loss After Bariatric Surgery, sponsored by Kasr El Aini Hospital. Completed. Open to participants aged 25 Years to 65 Years. Per ClinicalTrials.gov, last updated 2026-10-19.
Sponsored by Kasr El Aini Hospital · Observational
Some people who have had weight-loss (bariatric) surgery do not lose enough weight, regain much of the weight they lost, see obesity-related diseases such as diabetes or high blood pressure return, or develop complications of the first operation. Many of them need a second, revisional operation.
This study reviews the medical records of adults who had revisional bariatric surgery between 2017 and 2025 at a single surgical centre. It describes which revisional operations were performed after each type of first operation and measures how much weight patients lost 6 months, 12 months and up to 3 years after the revision. It also records whether obesity-related diseases and quality of life improved after the revision, and looks at patient factors linked to better weight loss.
Background Revisional bariatric surgery is performed when a primary bariatric operation results in insufficient weight loss or weight regain, when obesity-related comorbidities recur, or when complications of the primary operation require revision. The choice of revisional procedure depends largely on the primary operation, and outcome data across the range of primary and revisional procedures remain limited.
Design and setting Retrospective, single-centre, observational cohort study of patients who underwent revisional bariatric surgery in the Department of General Surgery between 2017 and 2025. Data are extracted from the centre's follow-up records. The study was approved by the scientific committee of the Department of General Surgery and the institutional research ethics committee, and is reported according to the STROBE guideline.
Data collected Age, sex and height; the primary bariatric procedure and its year; reflux (GERD) symptoms before and after the primary operation; complications of the primary operation; weight before the primary operation, the lowest weight reached after it and the weight before revision; the interval from the primary operation to weight rebound; satisfaction with weight loss after the primary operation; the revisional procedure and its date; weights at 6 months, 12 months and 3 years after revision; obesity-related comorbidities and their outcome after revision; and quality of life after revision.
Revisional procedures Roux-en-Y gastric bypass (RYGB), banded RYGB, one-anastomosis gastric bypass (OAGB), single-anastomosis duodeno-ileal bypass (SADI), SADI with sleeve gastrectomy (SADI-S), re-sleeve or conversion to sleeve gastrectomy (LSG), distalisation of a bypass, and reversal of the primary operation.
Definitions BMI = weight (kg) / height (m) squared. Weight regain = weight before revision minus the lowest weight after the primary operation. Total weight loss: %TWL = (weight before revision - follow-up weight) / weight before revision x 100. Excess weight loss: %EWL = (weight before revision - follow-up weight) / (weight before revision - weight at BMI 25 kg/m2) x 100, calculated only for patients with a recorded height. A successful result is defined as %EWL of 50% or more.
Data management Source data are cleaned before analysis (date conversion, standardisation of free text, checking of implausible values). Missing values are not imputed; each analysis is a complete-case analysis and the number of patients analysed is reported for every result.
Statistical analysis SPSS 27 and Python 3 (SciPy). Categorical variables as n (%) with Wilson 95% confidence intervals for the main proportions; continuous variables as mean +/- SD or median (IQR), with normality assessed by the Shapiro-Wilk test. Paired weights are compared with the paired t test and Wilcoxon signed-rank test (Cohen's d for paired samples); weights at the four time points with the Friedman test followed by pairwise Wilcoxon tests with Bonferroni correction. Independent groups are compared with the Mann-Whitney U or Kruskal-Wallis test; paired proportions with the exact McNemar test; unpaired proportions with Fisher's exact test or a permutation chi-square test. Associations are assessed with Spearman correlation, and a multiple linear regression examines factors associated with %TWL at 12 months after conversion procedures (age, sex, weight before revision, years from primary operation to revision, and LSG versus bypass-type revision). Reversal and distalisation operations are excluded from group comparisons and the regression. Tests are two-sided with p \< 0.05 considered significant; comparisons between revisional procedures are exploratory. The protocol sample-size calculation (alpha 0.05, power 80%) targeted 164 patients.
936 studies on the registry are indexed under Obesity, Morbid; 169 are open to participants now.
This study's enrollment of 96 is above the median of 77 across 311 observational studies indexed under Obesity, Morbid.
Browse Obesity, Morbid studies →Kasr El Aini Hospital is the lead sponsor of 283 studies on the registry; 33 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Adults aged 25 to 65 years who underwent revisional bariatric surgery in the Department of General Surgery between 2017 and 2025 after one or more previous bariatric operations, identified from the centre's follow-up records.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Adults aged 25 to 65 years who underwent revisional bariatric surgery between 2017 and 2025 after one or more previous bariatric operations, for insufficient weight loss, weight regain, recurrence of comorbidities or complications of the primary operation.
Procedure: Revisional bariatric surgery
Revisional or conversional bariatric operation after a previous bariatric procedure, as chosen by the treating team: Roux-en-Y gastric bypass (RYGB), banded RYGB, one-anastomosis gastric bypass (OAGB), single-anastomosis duodeno-ileal bypass (SADI), SADI with sleeve gastrectomy (SADI-S), re-sleeve or conversion to sleeve gastrectomy, distalisation of a bypass, or reversal of the primary operation.
Percentage of Total Weight Loss (%TWL) After Revisional Bariatric Surgery
Weight loss after revision expressed as the percentage of total weight loss (%TWL), calculated as: %TWL = \[(body weight before revision - body weight at follow-up) / body weight before revision\] x 100. Body weight is measured in kilograms (kg) on a clinic weighing scale before revision and at each follow-up visit, and recorded in the patient's follow-up file. Unit of measure: percentage (%) of pre-revision body weight.
Time frame: 6 months, 12 months and 3 years after revisional surgery
Percentage of Excess Weight Loss (%EWL) After Revisional Bariatric Surgery
Weight loss after revision expressed as the percentage of excess weight loss (%EWL), calculated as: %EWL = \[(body weight before revision - body weight at follow-up) / (body weight before revision - ideal body weight)\] x 100, where ideal body weight is the weight corresponding to a body mass index (BMI) of 25 kg/m2 for the patient's height. Body weight is measured in kilograms (kg) on a clinic weighing scale and height in metres (m); both are recorded in the patient's follow-up file. Unit of measure: percentage (%) of excess body weight.
Time frame: 6 months, 12 months and 3 years after revisional surgery
Percentage of Patients With Improvement of Obesity-Related Comorbidities After Revisional Surgery
Among patients with at least one obesity-related comorbidity before revision (such as hypertension, type 2 diabetes mellitus, dyslipidaemia or asthma), the percentage whose comorbidity improved after revision. Each comorbidity is assessed clinically by the treating surgical team at follow-up and recorded in the patient's follow-up file as "improved" or "not improved". Unit of measure: percentage (%) of patients.
Time frame: Up to 3 years after revisional surgery
Percentage of Patients Reporting Improved Quality of Life After Revisional Surgery
Patient-reported overall quality of life after revision compared with before revision. At follow-up, patients are asked whether their overall quality of life has improved after the revisional operation, and the answer is recorded in the patient's follow-up file as "improved" or "not improved". No validated quality-of-life questionnaire is used. Unit of measure: percentage (%) of patients.
Time frame: Up to 3 years after revisional surgery
Number of Patients With Complications of Revisional Surgery
Number of patients with any intraoperative or postoperative complication related to the revisional operation, as documented by the treating surgical team in the patient's medical and follow-up records. Unit of measure: number of patients.
Time frame: From the day of revisional surgery up to 3 years after surgery
No study locations are listed for this record.
Plan to share: No — Individual participant data will not be shared; aggregate results are reported in the publication.
No publications or documents are linked to this record.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
This study is completed, as verified in Oct 2026. You cannot join it, but the record below documents what was studied.
Get an email when the registry record changes — status, dates, results — or when someone posts here.
Sign in to followQuestions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.
Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.
Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.