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Veilleux et al. Mini-invasive Surg 2020;4:4 I http://dx.doi.org/10.20517/2574-1225.2020.01 Page 3 of 7

have comparatively advanced diabetes, with mean preoperative HbA1C at 9.2 ± 1.5, duration of disease of
[13]
8.5 ± 5.2 years, and 44% on insulin therapy preoperatively. In a study from Argentina, Viscido et al.
found much higher rates of remission at five years post sleeve gastrectomy (71%) in their cohort of patients,
of whom only 13% were on insulin preoperatively, and mean HbA1C was 7.15. As we might expect, of
their patients who were taking insulin preoperatively, the remission rate at five years was much lower at
[14]
37.5%. Sánchez-Pernaute et al. further supported this finding in a study of 97 patients undergoing single
anastomosis duodenal ileal bypass (SADI-S). Duodenal switch and SADI are regarded by many as the most
efficacious surgeries for diabetes. However, in their study, we still observe a large disparity in remission
rates in patients taking preoperative oral antidiabetics vs. insulin. Absolute remission rate in these two
groups was 92.5% vs. 47% at one year, and 75% vs. 38.4% at five years .
[14]
Indeed, we see large variability in the remission rates between studies, as a strong determining factor is
the patient selection and the severity of preoperative diabetes. This is acknowledged by the authors of
multiple studies when comparing their higher remission rates to that of the STAMPEDE trial, typically
[13]
quoting lower HbA1C, shorter duration of disease, and lower use of insulin in their patient populations .
The discerning reader must also be aware of the differing values that denote “remission” amongst the
various studies, which can yield results that appear inflated when cutoffs are less stringent. Further multi-
institutional studies inclusive of a broader, more generalizable range of patients with subgroup analysis will
help to elucidate accurate remission rates.

CHOICE OF PROCEDURE
Sleeve gastrectomy is currently the most common procedure performed for weight loss. When evaluating
the effectiveness of metabolic procedures on long-term diabetic improvement, current studies suggest
anastomotic procedures to be more efficacious over restrictive procedures, with duodenal switch
[6,7]
outperforming gastric bypass . However, many of the randomized controlled trials from which we
abstract these data were not powered to detect significant differences between procedures. Considering
[10]
this, Aminian et al. evaluated the pooled data from four randomized controlled trials [6,15-17] of T2DM
remission for sleeve and bypass (each providing at least five-year follow up data). Interestingly, they found
that there was no significant difference between procedures, or, at most, if we assume a difference exists
that the pooled power was insufficient to show, a 15% advantage in remission rate of bypass over sleeve
[10]
would exist .

[18]
In a larger, single center, triple blind, randomized controlled study from Norway, Hofsø et al. sought to
compare the effects of bypass vs. sleeve on remission of T2DM in obese individuals while also looking at
the improvement in β-cell function. With 107 patients at one-year follow up, they found a 75% remission
rate for gastric bypass and 48% remission rate for sleeve gastrectomy. Interestingly, despite a higher rate of
resolution with the bypass, the authors did not find a significant difference between procedures when they
assessed improvement in β-cell function. This was tested by the validated method of intravenous glucose
tolerance test.

Despite these results from randomized trials which tend to favor duodenal switch or gastric bypass, the
most efficacious procedure does not always equate to be the best choice for all patients. It can be easy to
lose sight of other mitigating variables when intending to follow the published evidence. At our practice,
we agree it is essential to consider a variety of factors when discussing procedure choice with our patients.
Clearly, there are several technical, nutritional, pathologic, pharmacologic, and behavioral factors that may
dictate the appropriateness of one procedure over another. However, in terms of guiding the choice as it
relates to metabolic improvement, it is important to consider the severity of the disease and ability of the
pancreas’ β-cell reserve to respond to the gastrointestinal modulatory effects of surgery.