Study Roundup

Published in February Issue             

Short-Term Preoperative Weight Loss and Postoperative Outcomes in Bariatric Surgery  (Journal of the American College of Surgeons)

To determine the impact short-term preoperative excess weight loss (EWL) on postoperative outcomes in patients undergoing primary bariatric surgery, 355 patients who completed a
4-week long low-calorie diet (LCD) immediately before sleeve gastrectomy (SG = 167) or Roux-en-Y gastric bypass (RYGB = 188) were divided into two cohorts: those who achieved 8% or greater EWL preoperatively (n = 224) and those who did not (n = 131). Patients achieving ≥8% EWL preoperatively experienced a greater percentage of EWL at 3 months (42.3% vs. 36.1%), 6 months (56.0% vs. 47.5%), and 12 months (65.1% vs. 55.7%) postoperatively. Patients achieving ≥8% EWL also had a shorter median operative duration (117 minutes vs. 125 minutes) and a shorter mean hospital stay (1.8 days vs. 2.1 days).
No significant differences were seen in follow-up, readmission or reoperation rates. Results suggest that patients who achieve ≥8% EWL during a 4-week LCD can lose 7.5% more excess weight in the first year after surgery.

Association of Bariatric Surgery Using Laparoscopic Banding, Roux-en-Y Gastric Bypass,
or Laparoscopic Sleeve Gastrectomy vs. Usual Care Obesity Management With
All-Cause Mortality
(Journal of the American Medical Association)

This retrospective cohort study assessed the association of bariatric surgery compared to nonsurgical treatment with mortality and clinical outcomes in patients enrolled in a large Israeli integrated health fund. In the study of 33,540 participants, patients who had bariatric surgery (n=8,385) between January 1, 2005, and December 31, 2014, were compared to individuals who received usual care obesity management only (n=25,155) – provided by a primary care physician, which may include dietary counseling and behavior modification – matched on age, sex, body mass index (BMI) and diabetes. Patients who underwent bariatric surgery (laparoscopic banding [n = 3635], Roux-en-Y gastric bypass [n = 1388], laparoscopic sleeve gastrectomy [n = 3362]) had a baseline median BMI of 40.6. Nonsurgical matched patients had a baseline median BMI of 40.5. There were 105 deaths (1.3%) among surgical patients during a median follow-up of 4.3 years (61 [1.7%] banding, 18 [1.3%] gastric bypass, and 26 [0.8%] sleeve gastrectomy), and 583 deaths (2.3%) among nonsurgical patients during a median follow-up of 4.0 years. The absolute difference was 2.51 fewer deaths per 1000 person-years in the surgical vs. nonsurgical group. Adjusted hazard ratios (HRs) for mortality among nonsurgical versus surgical patients were 2.02 for the entire study population. HRs were 2.01 for banding, 2.65 for gastric bypass, and 1.60 for sleeve gastrectomy. Compared with nonsurgical obesity management, bariatric surgery is associated with lower all-cause mortality over a median follow-up of approximately 4.5 years.

Association of Bariatric Surgery vs. Medical Obesity Treatment with Long-term
Medical Complications and Obesity-Related Comorbidities

(Journal of the American Medical Association)

Study compared changes in obesity-related comorbidities among patients with severe obesity (BMI ≥40 or ≥35 and at least one comorbidity) having bariatric surgery (n = 932, 92% gastric bypass) to those receiving specialized medical treatment including individual or group-based lifestyle intervention programs (n = 956) between November 2005 through July 2010 with follow-up data from 2006 through December 2015. Among 1,888 patients, baseline BMI was 44.2 and 100% of participants completed follow-up at a median of 6.5 years. Surgically treated patients had a greater likelihood of remission and lesser likelihood for new onset of hypertension (remission absolute risk [AR], 31.9% vs. 12.4%; new onset AR,
3.5% vs. 12.2%,), greater likelihood of diabetes remission (AR, 57.5% vs. 14.8%), greater risk of new-onset depression (AR, 8.9% vs. 6.5%) and treatment with opioids (AR, 19.4% vs. 15.8%). Surgical patients had a greater risk for undergoing at least one additional gastrointestinal surgical procedure (AR, 31.3% vs. 15.5%). The proportion of patients with low ferritin levels was significantly greater in the surgical group (26% vs. 12%). Data suggests bariatric surgery compared with medical treatment is associated with lower risks of obesity-related comorbidities, though, a “clinically important” increased risk for complications.

Evaluation of Weight Loss Indicators and Laparoscopic One-Anastomosis Gastric Bypass Outcomes (Nature)

Non-randomized prospective observational study of patients undergoing bariatric laparoscopic one-anastomosis gastric bypass (OAGB) analyzed weight loss progress in patients from the first pre-surgery appointment through a two-year follow-up, using weight-reduction indicators and surgically-inherent determinants including bowel loop length, surgery duration, associated complications, hospital stay, and weight loss at six postoperative points. In the study, 100 patients with a mean BMI of 42.61 had a mean surgery duration of 97.84 minutes and a mean biliopancreatic loop length of 274.95 cm. Average hospital stay was 24 hours in 98% of patients, and no surgical complications arose. Weight decreased significantly during follow-up, with the greatest weight loss observed at
12 months post-surgery (68.56 kg). The study suggests OAGB surgery is a safe and effective way to treat obesity.

Rate of Acute Hospital Admissions Before and After Roux-en-Y Gastric Bypass Surgery: A Population-based Cohort Study (Annals of Surgery)

To examine rates of acute inpatient hospital admissions, 9,985 patients undergoing
Roux-en-Y gastric bypass surgery in Denmark during 2006 to 2010 were compared to a matched population-based cohort of 247,375.Admissions for surgical complications occurred in 3.3% (n = 328) of gastric bypass patients <30 days after surgery and in 23.9% (n = 2367) during the entire follow-up period (median 4.2 years). Fifteen percent (n = 1486) were admitted with abdominal pain, 5.2% (n = 518) with intestinal obstruction during follow-up. Overall admission rates in gastric bypass patients versus comparisons were 11.5 versus 5.9 per 100 person-years before gastric bypass, increasing to 24.9 versus 7.1 per 100 person-years after gastric bypass. Incidence rate ratios (RRs) of cardiovascular and chronic pulmonary disease admissions decreased considerably. RRs increased for alcohol abuse (0.59 to 2.17), self-harm (suicide attempts, medication overuse: 1.72 to 3.61) anemia (0.84 to 17.92), and osteoporosis
(1.19 to 1.65). Short-term surgical complications occurred in 3% and long-term complications in one-fourth of gastric bypass patients. Compared with the general population, the RR for any inpatient admission increased after gastric bypass.

Mastery in Bariatric Surgery: The Long-term Surgeon Learning Curve of Roux-en-Y
Gastric Bypass
(Annals of Surgery)

To determine the learning curve needed to master gastric bypass, researchers studied the effect of cumulative volume on all-cause morbidity and the operative-time of 29 surgeons during their first six years of performing bariatric surgery in a high-volume, regionalized center of excellence system. The surgeons performed a total of 11,684 gastric bypass procedures, and the overall morbidity rate was 10.1%. Short-term outcomes were related significantly to cumulative volume, with perioperative risk plateauing after approximately 500 cases. The perioperative risk was lowest for surgeons who had completed more than 600 cases (odds ratio 0.53) compared to the first 75 cases. Operative-time also stabilized after about 500 cases, with an operative-time 44.7 minutes faster than surgeons in their
first 75 cases.

Meta-analysis of Metabolic Surgery versus Medical Treatment for Microvascular Complications in Patients with Type 2 Diabetes Mellitus (British Journal of Surgery)

This review of 10 studies, including 17,532 patients, assessed the effect of metabolic surgery to medical treatment on pre-existing and future microvascular complications in patients with type 2 diabetes. In patients with diabetes, metabolic surgery prevented the development of microvascular complications better than medical treatment (odds ratio 0.26). Pre-existing diabetic nephropathy was also “remarkably improved” by metabolic surgery compared with medical treatment (odds ratio 15.41).

Clinical and Patient-Centered Outcomes in Obese Type 2 Diabetes Patients 3 Years After Randomization to Roux-en-Y Gastric Bypass Surgery Versus Intensive Lifestyle Management: The SLIMM-T2D Study (Diabetes Care)

The study compares the effect of Roux-en-Y gastric bypass surgery versus intensive medical diabetes and weight management (IMWM) on clinical and patient-reported outcomes in patients with obesity who have type 2 diabetes. Researchers randomized 38 patients with obesity and diabetes (mean BMI 36.3, age 52 years, HbA1c 8.5%) to gastric bypass (n = 19) or IMWM (n = 19). After three years, the gastric bypass group had greater weight loss, losing on average 24.9 kg compared to the 5.2 kg in the IMWM group, lowered their HbA1C by 1.79% compared to 0.39% in the IMWM group. Changes in cardiometabolic risk for coronary heart disease and stroke and improvements in obesity-related quality of life were all more favorable in RYGB versus IMWM patients.

Insurance-Mandated Pre-Operative Diet and Outcomes Following Bariatric Surgery (SOARD)

The study compared weight loss outcomes at 6, 12, and 24 months after bariatric surgery between patients who participated in insurance mandated pre-operative diet and those that did not. Patients had either laparoscopic Roux-en-Y gastric bypass (RYGB) or sleeve gastrectomy (SG) over a five-year period. Of 284 patients, 225 (79%) were required, and
59 (21%) were not required to complete a pre-operative diet by their insurance provider. Patients without the requirement had a shorter time to operation from initial consultation, were older and were more likely to have government-sponsored insurance. There was no difference in pre-operative weight or BMI or comorbidities. Percentage of excess weight loss was superior in the group without an insurance-mandated diet at 6, 12 and 24 months, and had a greater percentage of total weight loss at 24 months and change in BMI at 6 and 24 months. There was no difference in length of stay or complication rates. Results indicate that insurance-mandated pre-operative diets delay treatment and may lead to inferior weight loss.