Parsing safety and efficacy of this procedure isn’t easy, given the studies at hand, said Dr. McKenzie: “The data are plagued by short follow-up, low numbers, and inconsistent quality.” Of the 14 case series following 1,045 patients, none include randomized controlled data, he said.
The data that are available show total body weight loss in the 34%-39% range, with little difference between losses seen at 1 year and 2 years.
However, said Dr. McKenzie, one 100-patient case series showed that SADI-S patients averaged 2.5 bowel movements daily after the procedure, and two patients needed surgical revision because they were experiencing malnutrition. Anemia, vitamin B12 and D deficiencies, and folate deficiency are all commonly seen two years after SADI-S procedures, he said.
“The OADS procedure is very effective, although better data are needed before drawing conclusions,” said Dr. McKenzie.
A gastric bypass variation known as the “mini” bypass, or the one anastomosis gastric bypass (OAGB), is another less common bariatric technique. In this procedure, a small gastric pouch is created that forms the working stomach, which is then connected to the duodenum with bypassing of a significant portion (up to 200 cm) of the small intestine. This procedure causes both restrictive and malabsorptive weight loss, and is usually performed using minimally invasive surgery.
Four randomized controlled trials exist, said Dr. McKenzie, that compare OAGB variously to Roux-en-Y gastric bypass (RYGB) and to sleeve gastrectomy. In an 80-patient study that compared OAGB with RYGB at two years post-procedure, excess weight loss was similar, at 60% for OAGB versus 64% for RYGB ( Ann Surg. 2005;24[1]20-8). However, morbidity was less for OAGB recipients (8% vs 20%, P less than .05).
Another study looked at OAGB and sleeve gastrectomy in 60 patients, following them for 5 years. Total body weight loss was similar between groups at 20%-23%, said Dr. McKenzie (Obes Surg. 2014;24[9]1552-62).
“But what about bile reflux?” asked Dr. McKenzie. He pointed out that in OAGB, digestive juices enter the digestive path very close to the outlet of the new, surgically created stomach, affording the potential for significant reflux. Calling for further study of the frequency of bile reflux and potential long-term sequelae, he advised caution with this otherwise attractive procedure.
Those caring for bariatric patients may also see the consequences of “rogue” procedures on occasion: “Interest in metabolic surgery has led to some ‘original’ procedures, many of which are not based on firm science,” said Dr. McKenzie. An exemplar of an understudied procedure is the sleeve gastrectomy with a loop bipartition, with results that have been published in case reports, but whose longer-term outcomes are unknown.
“Caution is advised regarding operations that are devised outside of study protocols,” said Dr. McKenzie.
Dr. McKenzie reported that he had no relevant financial disclosures.
SOURCE: McKenzie, T. AACE 2018, presentation SGS4.