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Journal Watch 4/01/2023

Welcome to our weekly round-up of the latest bariatric and obesity-related papers published in the medical literature. As ever, we have looked far and wide to give you an overview of papers including VTE prophylaxis after bariatric surgery, cost-effectiveness of SLR, dementia in bariatric surgery patients, long-term weight loss or associated medical outcomes in matched primary-LSG and revisional-LSG patients, and acute care utilisation and costs after LSG and RYGB (please note, log-in maybe required to access the full paper).

Venous Thromboembolism (VTE) Prophylaxis after Bariatric Surgery: A National Survey of MBSAQIP Director Practices

Writing on behalf of the ASMBS research committee, researchers have reported the outcomes from a web-based survey to Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program (MBSAQIP) medical directors and ASMBS members, that examined the differences in clinical practice regarding the administration of venous thromboembolism (VTE) prophylaxis after metabolic/bariatric surgery (MBS).

The study included 264 metabolic/bariatric surgeons (136 medical directors and 128 ASMBS members) and reported that both mechanical and chemical VTE prophylaxis was used by 97.1% of the participants, knee-high compression devices by 84.7%, enoxaparin (32.4% 40 mg every 24 hours, 22.7% 40 mg every 12 hours, 24.4% adjusted the dose based on body mass index [BMI]) by 56.5%, and heparin (46.1% 5000 units every 8 hours, 22.6% 5000 units every 12 hours, 20.9% 5000 units once preoperatively) by 38.1%.

Most surgeons (81.6%) administered the first dose preoperatively, while the first postoperative dose was given on the evening of surgery by 44% or the next morning by 42.2% and 86.3% used extended chemoprophylaxis for all or select patients, while 13.7% did not. Extended VTE prophylaxis was prescribed for 2 weeks by 38.7% and 4 weeks by 28.9%. No clinically significant differences were detected between the responses of medical directors and the AMSBS members.

They concluded that VTE prophylaxis practices vary widely among metabolic/bariatric surgeons and the variability may be related to limited available comparative evidence. Further large prospective clinical trials are needed to define optimal practices for VTE risk stratification and prophylaxis in bariatric surgery patients.

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Cost-effectiveness of Staple Line Reinforcement in Laparoscopic Sleeve Gastrectomy

Researchers from the University of Michigan Medical School, Ann Arbor, MI, have found that compared with standard stapling, reinforced stapling reduces minor postoperative bleeding but not major bleeding or leaks and is not cost-effective if routinely used in laparoscopic sleeve gastrectomy.

Writing in the Annals of Surgery, they performed a cost-effectiveness analysis of staple-line reinforcement in laparoscopic sleeve gastrectomy. For their study, two intervention arms were modelled: staple-line reinforcement and standard nonreinforced stapling. Bleed and leak rates and Thirty-day treatment costs were obtained from national and state registries. Quality-adjusted life-year (QALY) values were drawn from previous literature and device prices were drawn from institutional data. A final incremental cost-effectiveness ratio was calculated, and one-way and probabilistic sensitivity analyses were performed.

A total of 346,530 patient records from 2012 to 2018 were included. Complication rates for the reinforced and standard cohorts were 0.05% for major bleed in both cohorts (p= 0.8841); 0.45% compared with 0.59% for minor bleed (p< 0.0001); and 0.24% compared with 0.26% for leak (p= 0.4812).

The median cost for a major bleed was $5552 ($3287, $16,817) and $2,406 ($1861, $3484) for a minor bleed. Median leak cost was $9897 ($4589, $21,619) and median cost for patients who did not experience a bleed, leak, or other serious complication was $1908 ($1712, $2739). Mean incremental cost of reinforced stapling compared with standard was $819.60/surgery. Net QALY gain with reinforced stapling compared with standard was 0.00002. The resultant incremental cost-effectiveness ratio was $40,553,000/QALY. One-way and probabilistic sensitivity analyses failed to produce a value below $150,000/QALY.

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Development of dementia in patients who underwent bariatric surgery

Investigators from the University of Utah have found an increased hazard for dementia in individuals who underwent bariatric surgery, compared to matched non-surgical subjects.

Reporting in Surgical Endoscopy, the purpose of their study was to assess the long-term risk of dementia following bariatric surgery. Adult subjects (≥ 18 years old) at time of surgery (1996–2016) were matched with non-surgical subjects. The final sample included 51,078 subjects (1:2 matching); surgery group n=17,026; non-surgery subjects n=34,052).

Average (SD) age of the subjects was 42 (12) years old at surgery or matched baseline year, 78% were female and mean follow-up time was 10.5 years. 1.4% of the surgery group and 0.5% of the control group had an incidence of dementia. Controlling the covariates in the Cox regression, the surgery group had a higher risk for dementia incidence than the matched non-surgery subjects (HR = 1.33, p=0.02).

The authors cautioned that additional long-term data is needed to verify this association.

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Long-Term Matched Comparison of Primary and Revisional Laparoscopic Sleeve Gastrectomy

Israeli researchers have found that there were no significant differences in long-term weight loss or associated medical condition outcomes in matched primary-LSG and revisional-LSG patients.

Between May 2006, and December 2016, 194 matched patients with severe obesity (mean BMI 44.1 ± 6.7 kg/m2; age 44.2 ± 10.0 years, 67.0% female) underwent p-LSG (n=97) or r-LSG (n=97) and were followed for a mean 12.1 ± 1.5 vs 7.6 ± 2.1 years.

Respective mean weight regain from nadir was 15.0 ± 14.4 kg vs 11.9 ± 12.2 kg. Respective percent mean total weight loss and excess weight loss were 20.9 ± 12.7% and 51.8 ± 33.1%, and 18.3 ± 12.8% and 43.4 ± 31.6% at last follow-up, with no significant difference between groups. Resolution of type 2 diabetes (HbA1C < 6.5%, off medications) was 23.1% vs 11.1%; hypertension 36.0% vs 16.0%; and hyperlipidaemia 37.1% vs 35.3%.

Patients in the pLSG group were significantly more satisfied with LSG (59.8% vs 43.3%, p<0.05) and more likely to choose the procedure again.

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Acute Care Utilization and Costs Up to 4 Years After Index Sleeve Gastrectomy or Roux-en-Y Gastric Bypass

Researchers led by Harvard Medical, School, Boston, MA, have reported that sleeve gastrectomy (SG) may have fewer complications requiring emergency care and hospitalization, especially as related to digestive system disease, compared to Roux-en-Y gastric bypass (RYGB) however, any acute care cost advantages of SG may wane over time.

Writing in the Annals of Surgery, they authors sought to compare acute care utilization and costs of the two procedures using a national insurance claims database. Patients were matched on age, sex, calendar-time, diabetes, and baseline acute care use. The researchers used adjusted Cox proportional hazards to compare acute care utilization and two-part logistic regression models to compare annual associated costs (odds of any cost, and odds of high costs, defined as ≥80th percentile), between SG and RYGB, overall and within several clinical categories.

The matched cohort included 4263 SG and 4520 RYGB patients. Up to 4 years after surgery, SG patients had slightly lower risk of ED visits [adjusted hazard ratio (aHR): 0.90; 95% confidence interval (CI): 0.85,0.96] and inpatient stays (aHR: 0.80; 95% CI: 0.73,0.88), especially for events associated with digestive-system diagnoses (ED aHR: 0.68; 95% CI: 0.62,0.75; inpatient aHR: 0.61; 95% CI: 0.53,0.72).

SG patients also had lower odds of high ED and high total acute costs (eg, year-1 acute costs adjusted odds ratio (aOR) 0.77; 95% CI: 0.66,0.90) in early follow-up. However, observed cost differences decreased by years 3 and 4 (eg, year-4 acute care costs aOR 1.10; 95% CI: 0.92,1.31).

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