Clinical Trial Details
— Status: Completed
Administrative data
| NCT number |
NCT01486680 |
| Other study ID # |
NTY/11/07/082 |
| Secondary ID |
ACTRN12611000751 |
| Status |
Completed |
| Phase |
N/A
|
| First received |
|
| Last updated |
|
| Start date |
September 2011 |
| Est. completion date |
October 2019 |
Study information
| Verified date |
September 2021 |
| Source |
North Shore Hospital, New Zealand |
| Contact |
n/a |
| Is FDA regulated |
No |
| Health authority |
|
| Study type |
Interventional
|
Clinical Trial Summary
Type 2 diabetes (T2DM) and obesity are becoming increasingly common in New Zealand (NZ) and
worldwide. Both are associated with a risk of early mortality (death). Whilst weight loss
surgery is known to be effective for weight loss, current research suggests that it may also
be effective in resolving T2DM in around 60-80% of patients, with some no longer requiring
their medication. The mechanism for this remains unclear.
Two main types of weight loss surgery are performed in NZ public hospitals, which include
gastric bypass and sleeve gastrectomy. The gastric bypass is a more complex procedure
compared to the sleeve gastrectomy. Whilst both appear to be effective for weight loss (with
most patients losing more than 60% of their excess weight), it is still not known which one
is better for treating T2DM.
This study will therefore compare which of these two surgical procedures is most effective at
treating T2DM in obese patients, as well as comparing whether there are any differences in
the amount of weight lost, side effects and quality of life.
Description:
EFFECTS OF DIABETES AND OBESITY The World Health Organization indicates that 346 million
people worldwide have diabetes. This is expected to double between 2005 and 2030. Type 2
diabetes mellitus (T2DM) accounts for 90% of people with diabetes and is known to result from
a combination of physical inactivity and excess weight. In New Zealand (NZ) more than 200,000
people have diabetes, with an incidence amongst the Maori and Pacific population three times
greater than other NZ ethnic groups. Obesity is also more prevalent amongst this population,
with each 5 kg/m2 higher BMI resulting in a 30% higher overall mortality.
Over the last 10 years bariatric surgery has been recognised as an effective strategy to
treat both morbid obesity and T2DM. Indeed in a systematic review in 2004, by Buchwald et al,
an overall T2DM remission rate of 76% was seen following bariatric surgery. In March 2011 the
International Diabetic Federation released a position statement recognising bariatric surgery
as an appropriate treatment option in those patients with T2DM and a body mass index (BMI)>
OR = 35kg/m2 or BMI 30-35kg/m2 where medical treatment has failed.
SURGICAL PROCEDURES Laparoscopic Roux-en-Y gastric bypass (LRYGB): Currently the most
commonly performed bariatric procedure worldwide. It combines a restrictive and malabsorptive
(duodenal bypass) component, with a mean excess weight loss (EWL) of 61.6% and T2DM remission
rate of 83.8% reported. Analysis of our own series identified a T2DM remission rate at 1 year
of 88%.
Laparoscopic sleeve gastrectomy (LSG): A predominantly restrictive procedure (no bypass
component), which was initially used as a staged approach to biliopancreatic diversion and
duodenal switch (BPD-DS), has gained increasing popularity due its relatively lower technical
complexity. In a recent systematic review a mean EWL of >45% (range 6.3 - 74.6%) was reported
with an overall T2DM remission rate of 66%, which reduced to 59% where only those studies
reporting 1 year outcomes were analysed. There is however a lack of medium and long term data
and meta-analysis is currently not feasible in view of the high heterogeneity of studies and
the lack of randomised controlled trials.
MECHANISM OF ACTION The mechanism of T2DM remission following these procedures remains
unclear and may relate to the effects of reduced caloric intake or gut hormone effects in the
proximal and distal intestine. Following LRYGB, the improvement in glycaemic control appears
to occur before weight loss and may be explained by exclusion of the duodenum / proximal
jejunum reducing insulin resistance or an enhanced hormonal response resulting from nutrients
in the distal small bowel. Following LSG both hormonal changes and a hindgut theory have been
proposed. In addition there is increasing evidence that changes in bone mineral density and
body composition, with a reduction in body fat and lean tissue mass, and an increase in
resting energy expenditure, may also occur following gastric bypass and other restrictive
surgical procedures. It is unclear whether such changes correlate with the degree of
comorbidity resolution after surgery.
CONCLUSION At the current time much of the data relating to LSG is based on non-randomised
observational studies and it remains unclear whether the promising T2DM remission rates and
excess weight loss reported will be sustainable in the long term. In the only published
randomised trial, by Lee et al. from Taiwan, to compare T2DM remission rates at 1 year
between LSG and gastric bypass in BMI < 35, a much higher remission rate of 93% was seen
following gastric bypass compared with 47% following LSG. Given the potential technical
benefits of LSG, there is an urgent need to compare the efficacy of this procedure with the
more commonly performed LRYGB procedure, at a time when clinical equipoise remains, in order
to determine the optimum approach to T2DM in the future.