The effect of protein supplementation on body muscle mass and fat mass in post-bariatric surgery: a randomized controlled trial (RCT) study protocol

Severe weight loss through means of bariatric surgery has been associated with loss of muscle mass due to lack of absorption of protein. The aim of this RCT is to investigate the effectiveness of protein supplementation in reducing the risk of developing protein malnutrition and muscle wasting in post-bariatric surgery patients in Qatar.

The study was based at the Department of bariatric and metabolic surgery, Doha metropolitan and regional areas. It is envisaged that approximately 160 post-bariatric surgery patients will be randomized and followed up for 6 months. These will be males and females obese (BMI >35) Qatari patients between the aged 18–60 years. Subjects with renal or liver disease and those with past history of bariatric surgery will be excluded. By the completion of the trial, patients who took less than 80% of the supplement will be further excluded from the final analysis. Protein supplement (Cubitan,Protein, Nutricia, Netherlands) that contain daily intake of 20 g of protein to be taken orally 3 times a day throughout the study period. The placebo group will receive identical ampule containing zero-protein with exact instructions as per the intervention group. Body weight, muscle and fat mass, total protein, albumin, vit B12, Magnesium and Zinc will be measured at baseline and every follow up/study visit. Study variables will be compared between the 2 groups at different stages of the trial, including baseline, using Sample T-test (paired and unpaired) and the significance level will be confirmed with the 95% confidence interval with alpha error set to 0.05.

Protein supplementation for post-bariatric patients is not yet a standard procedure at Hamad Medical Corporation in Qatar and requires an RCT to establish evidence-based clinical practice guidelines. This study was approved by the Hamad Medical Corporation IRB and MRC committees (approval no. 16433/16).

ClinicalTrials.gov NCT03147456 (registration date: 18 April 2017).

One major strength of our study is that our population is a distinctive population (Qatari Obese patients) where results from international studies may not apply to the local and unique context. A local study like ours will provide healthcare providers in Qatar an opportunity to ensure good clinical practice and healthy and sustainable weight loss following bariatric surgery.

The well-designed double-blinded RCT will almost certainly provide us with the evidence-based clinical practice guideline that we seek as health professionals.

One limitation of our study is the slight discrepancy in caloric content of the intervention and the placebo (250 cal and 100 cal, respectively). However, it is the intervention that has the higher caloric content, in which case it may not influence the results in the direction of our hypothesis that protein supplementation leads to lower fat mass and higher muscle mass.

Another limitation is that the use of the intervention and the placebo are not objectively measured. However, all efforts will be made to ensure compliance and reporting of consumption of products.

A third limitation could be loss to follow up. Participants may cease to participate, particularly, once they have lost “sufficient’ weight and gained the fitness to consume any type of foods they desire. This is common in late stages of post-bariatric surgery (beyond 3 months). We feel that this may be a challenge, particularly in reference to our specific population. However, such findings albeit negative, should serve in improving the clinical practice delivered by healthcare providers.