Five years out, sleeve gastrectomy had a lower risk of mortality, complications, and reinterventions than gastric bypass, but there was a higher risk of surgical revision, including conversion to another bariatric surgery, gastrectomy, or anastomotic revision, according to a new analysis.
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Sleeve gastrectomy has gained rapid popularity, and now represents 60% of all bariatric procedures. It has demonstrated good efficacy and short-term safety, it is easier to perform than laparoscopic Roux-en-Y gastric bypass, and it is a safe option for high-risk patients, authors led by Ryan Howard, MD, of University of Michigan, Ann Arbor, wrote in JAMA Surgery.
Still, there are few comparative data on the long-term efficacy of the two procedures. Randomized, controlled trials have conducted long-term follow-up, but their small size has made it difficult to detect differences in rare outcomes. Observational studies are limited by the potential for bias. A novel approach to limiting bias is instrumental variables analysis, which controls for possible confounding using a factor that impacts treatment choice, but not patient outcome, to control for possible confounders. Studies using this approach confirmed the superior safety profile of sleeve gastrectomy in the short term.
The current study’s authors, used that method to examined 5-year outcomes in a Medicare population, in which obesity and its complications are especially frequent. Partly because of that lack of data, the Medical Evidence Development and Coverage Committee has called for more data in older patients and in patients with disabilities.
The researchers analyzed data from 95,405 Medicare claims between 2012 and 2018, using state-level variation in sleeve gastrectomy as the instrumental variable.
Dr. Ryan Howard
At 5 years, sleeve gastrectomy was associated with a lower cumulative frequency of mortality (4.27%; 95% confidence interval, 4.25%-4.30% vs. 5.67%; 95% CI, 5.63%-5.69%]), complications (22.10%; 95% CI, 22.06%-22.13% vs. 29.03%; 95% CI, 28.99%-29.08%), and reintervention (25.23%; 95% CI, 25.19%-25.27% vs. 33.57%; 95% CI, 33.52%-33.63%). At 5 years, surgical revision was more common in the sleeve gastrectomy group (2.91%; 95% CI, 2.90%-2.93% vs. 1.46%; 95% CI, 1.45%-1.47%).
The sleeve gastrectomy group had lower odds of all-cause hospitalization at 1 year (adjusted hazard ratio, 0.83; 95% CI, 0.80-0.86) and 3 years (aHR, 0.94; 95% CI, 0.90-0.98), as well as emergency department use at 1 year (aHR, 0.87; 95% CI, 0.84-0.90) and 3 years (aHR, 0.93; 95% CI, 0.90-0.97). There was no significant difference between the two groups at 5 years with respect to either outcome.
The effort to understand long-term outcomes of these two procedures has been challenging because follow-up is often incomplete, and because reporting isn’t always standardized, according Anita P. Courcoulas, MD, MPH, and Bestoun Ahmed, MD, in an accompanying editorial in JAMA Surgery. They noted that the differences in mortality is a new finding and the difference in surgical revisions confirmed something often seen in clinical practice. “Overall, these novel methods, which creatively balance unmeasured factors, have succeeded in providing important incremental findings about the long-term comparative safety outcomes between bariatric procedures that will be helpful in clinical practice,” the editorial authors wrote.
The complications discussed in the study are also difficult to interpret, according to Ali Aminian, MD, who is a professor of surgery and director of Bariatric and Metabolic Institute at Cleveland Clinic. They may be related to the surgery, or they may be complications that accrue as patients age. “So that doesn’t mean those were surgical complications, but [the findings are] in line with the other literature that [gastric sleeve] may be safer than gastric bypass, but in a different cohort of patients,” said Dr. Aminian, who was asked to comment.
“I thought it validated that which many of us in clinical practice see on a day to day basis,” said Shanu Kothari, MD, chair of surgery at Prisma Health, and the current president of American Society for Bariatric and Metabolic Surgery. He pointed out that the study was limited by its reliance on administrative claims, which makes it impossible to know the reduction in weight and obesity-related comorbid conditions following the procedures, as well as factors driving individual decisions: A surgeon might offer sleeve to a patient at higher risk of complications, but a gastric bypass to someone with more comorbidities. “What we don’t know is how to interpret this 35,000-foot view of Medicare data to that conversation with the patient sitting right in front of you,” said Dr. Kothari.
The authors similarly cited the “lack of clinical granularity in administrative claims data” among study limitations, as well as how the use of instrumental variables may leave the findings less applicable to patients more strongly indicated for one procedure over the other.
“Longer-term randomized clinical trials and observational studies are warranted to confirm these findings,” the study authors concluded. “Understanding the risk profile of various bariatric operations may further help patients and surgeons make the most appropriate decisions regarding plans of care.”
The study was funded by the National Institute of Diabetes and Digestive and Kidney Diseases. Some study authors and editorialists reported funding from various groups and institutions, such as the National Institutes of Health and the VA Ann Arbor Health System. Dr. Kothari and Dr. Aminian have no relevant financial disclosures.