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 the risk of oesophageal and gastric cancer after bariatric surgery, RYGB decreases myocardial infarction but not ischaemic stroke, common barriers to shared decision-making around bariatric surgery, patient perceptions on alcohol use after bariatric surgery, out-of-pocket costs LSG and RYGB, Caucasian race and female sex are risk factors for developing cholelithiasis after bariatric surgery and BMI may be associated with modified response to vitamin D supplementation (please note, log-in maybe required to access the full paper).
Risk of Esophageal and Gastric Cancer After Bariatric Surgery
French researchers have found that bariatric surgery is associated with a significant reduction of oesophageal and gastric cancer incidence and overall in-hospital mortality, suggesting bariatric surgery can be performed as treatment for severe obesity without increasing the risk of these cancers.
Writing in JAMA Surgery, the investigators compared the incidence of oesophageal and gastric cancer between patients with obesity who underwent bariatric surgery (adjustable gastric banding, gastric bypass and sleeve gastrectomy) and those who did not (control group). The main outcome was incidence of esophageal and gastric cancer. A secondary outcome was overall in-hospital mortality.
The study included 303,709 patients who underwent bariatric surgery (245,819 females [80.9%]; mean [SD] age, 40.2 [11.9] years) and matched 1:2 with 605,140 patients who did not receive surgery (500,929 females). After matching, a total of 337 patients had esophagogastric cancer: 83 in the surgical group and 254 in the control group. The incidence rates were 6.9 per 100 000 population per year for the control group and 4.9 per 100 000 population per year for the surgical group, resulting in an incidence rate ratio of 1.42 (95% CI, 1.11-1.82; p=0.005). The hazard ratio (HR) of cancer incidence was significantly in favour of the surgical group (HR, 0.76; 95% CI, 0.59-0.98; p=0.03). Overall mortality was significantly lower in the surgical group (HR, 0.60; 95% CI, 0.56-0.64; p<0.001).
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Risk of Myocardial Infarction, Ischemic Stroke, and Mortality in Patients Who Undergo Gastric Bypass for Obesity Compared With Nonoperated Obese Patients and Population Controls
Swedish researchers have reported that Roux-en-Y gastric bypass (RYGB) decreases myocardial infarction but not ischaemic stroke, according to a study published in the Annals of Surgery.
The aim of this study was to estimate risks of myocardial infarction, ischemic stroke and cardiovascular-related and all-cause mortality after RYGB for obesity (n=28,204) vs. non-operated obese patients and matched non-obese population controls (n=40,827).
RYGB patients had a reduced risk of myocardial infarction [HR=0.44 (95% CI 0.28-0.63)], similar risk of ischemic stroke [HR=0.79 (95% CI 0.54–1.14)] and decreased risks of cardiovascular-related [HR=0.47 (95% CI 0.35–0.65)] and all-cause mortality [HR=0.66 (95% CI 0.54–0.81)] within the first three years of follow-up, but not later.
Compared with non-obese population controls, RYGB patients had excess risks of ischemic stroke [HR=1.57 (95% CI 1.08–2.29)], cardiovascular-related mortality [HR=1.82 (95% CI 1.29–2.60)] and all-cause mortality [HR=1.42 (95% CI 1.16–1.74)], but not of myocardial infarction [HR=1.02 (95% CI 0.72–1.46)].
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Identifying barriers to shared decision-making about bariatric surgery in two large health systems
Health systems face numerous barriers to shared decision-making (SDM) around bariatric surgery, and these can be easily identified and prioritised by multistakeholder teams, according to a paper published in Obesity.
US authors stated the aim of the study was to identify and prioritise barriers to SDM around bariatric surgery to help guide implementation of SDM. Two large US health care systems formed multidisciplinary teams to facilitate the implementation of SDM around bariatric surgery. The teams used a nominal group process approach involving (1) generation of multilevel barriers, (2) round-robin recording of barriers, (3) facilitated discussion, and (4) selection and ranking of barriers according to importance and feasibility to address.
One health system identified 13 barriers and prioritised five as the most important and feasible to address. The second health system identified 14 barriers and prioritised 6. Both health systems commonly prioritised six barriers: lack of insurance coverage; lack of understanding of insurance coverage; lack of organizational prioritisation of SDM; lack of knowledge about bariatric surgery; lack of interdepartmental clarity between primary and specialty care; and limited training on SDM conversations and tools.
They concluded that future research should seek to identify effective strategies to address these common barriers.
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Patient perceptions regarding alcohol use after bariatric surgery
Patients consume alcohol after bariatric surgery for a variety of reasons and they do not believe recommending abstinence is useful, according to US researchers writing in Surgical Endoscopy.
Bariatric patients are at increased risk of an alcohol use disorder and this study was designed purpose of this study was to identify factors associated with post-surgical alcohol use. Twenty patients who were 1–3 years post-bariatric surgery and were consuming alcohol at least twice monthly participated in a 60-min interview. Participants responded about their knowledge regarding risk of post-surgical alcohol use and reasons why patients may start drinking.
Although nearly all participants were aware of the risks associated with post-surgical alcohol use, most believed that lifelong abstinence from alcohol was unrealistic. Common reasons identified for using alcohol after bariatric surgery included social gatherings, resuming pre-surgical use, and addiction transfer. Inductive coding identified three themes: participants consumed alcohol in different ways compared to prior to surgery; the effect of alcohol was substantially stronger than pre-surgery; and beliefs about why patients develop problematic alcohol use following surgery.
They concluded that understanding patient perceptions can inform interventions to minimise alcohol use after bariatric surgery and modifying traditional alcohol relapse prevention strategies may provide a more robust solution to decreasing negative outcomes experienced by individuals undergoing bariatric surgery.
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Out-of-pocket Costs for Commercially-insured Patients in the Years Following Bariatric Surgery Sleeve Gastrectomy Versus Roux-en-Y Gastric Bypass
A study examining the association between bariatric surgery procedure and out-of-pocket (OOP) costs have report differences between procedures of approximately US$100 per year, which may be an important factor for some patients deciding whether to pursue laparoscopic sleeve gastrectomy (SG) or Roux-en-Y gastric bypass (RYGB).
US researchers, reporting in Annals of Surgery, compared OOP costs for patients up to three years after bariatric surgery in a large, commercially-insured population. Of 63,674 patients, 64% underwent SG and 36% underwent RYGB. Adjusted OOP costs after SG were $1083, $1236, and $1266 postoperative years 1, 2, and 3.
For RYGB, adjusted OOP costs were $1228, $1377, and $1369. In their primary analysis, SG OOP costs were $122 (95% confidence interval [CI]: –$155 to –$90) less than RYGB year 1. This difference remained consistent at –$119 (95%CI: –$158 to –$79) year 2 and –$80 (95%CI: –$127 to –$35) year 3. These amounts were equivalent to relative differences of –7%, –7%, and –5% years 1, 2, and 3. Plan features contributing the most to differences were co-insurance years 1, 2, and 3.
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Incidence and risk factors for cholelithiasis after bariatric surgery: a systematic review and meta-analysis
Caucasian race and female sex are risk factors for developing cholelithiasis after bariatric surgery, according to the outcomes from a systematic review and meta-analysis by Chinese researchers.
Writing in Lipids in Health and Disease, they explored the risk factors for post-operative cholelithiasis after weight-loss surgery and propose suggestions for clinical decision making. A total of 19 articles were included in this meta-analysis (20,553 patients) Sex [OR = 0.62, 95% CI (0.55, 0.71), p<0.00001] and race [OR = 1.62, 95% CI (1.19, 2.19), p=0.002] were risk factors for cholelithiasis after bariatric surgery.
The researchers noted that surgical procedure, BMI, weight loss ratio, hypertension, diabetes mellitus, dyslipidaemia and smoking are not risk factors for cholelithiasis after bariatric surgery.
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Association of Body Weight With Response to Vitamin D Supplementation and Metabolism
US researchers have reported that BMI may be associated with modified response to vitamin D supplementation and may in part explain the observed diminished outcomes of supplementation for various health outcomes among individuals with higher BMI.
Writing in JAMA Network Open, they investigated whether baseline BMI modifies vitamin D metabolism and response to supplementationm using data from VITAL - a completed randomised, double-blind, placebo-controlled trial for the primary prevention of cancer and cardiovascular disease. In the present cohort study, an analysis was conducted in a subset of VITAL participants who provided a blood sample at baseline and a subset with a repeated sample at 2 years’ follow-up.
Compared with placebo, randomisation to vitamin D supplementation was associated with an increase in total 25-OHD, 25-OHD3, FVD, and BioD levels compared with placebo at 2 years’ follow-up, but increases were significantly lower at higher BMI categories (all treatment effect interactions p<0.001). Supplementation did not substantially change VDBP, albumin, PTH, or calcium levels.
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