the effect of bariatric surgery on type 2 diabetes mellitus gastric bypass versus gastric banding an...

The Effect of Bariatric Surgery on Type 2 Diabetes Mellitus

Gastric Bypass versus Gastric BandingAn Integrative Literature Review

Mary Jane Concengco, BSN, RN, NP Resident

University of Central Florida

Research QuestionIn morbidly obese adults with type 2

diabetes mellitus, does gastric bypass improve or resolve diabetes

better than gastric banding?


Background & Significance• In 2008 - 34% American adults are

Obese (32% men, 36% women); 17% children & teens (Flegal, Carroll, Ogden, & Curtin, 2010)

• Healthy People 2010 goal on obesity prevalence = all 50 States <15%

• 2010 – NO state reached the goal; • 12 states have obesity prevalence

>30% (CDC, 2011)


Obesity• Increased risk for development of HTN,

CVD, strokes, CA, hyperlipidemia, & T2DM (NHLBI, 1998).

• In 2008 - Medical costs for obesity related conditions est. @ $147 billion (Finkelstein, Trogdon, Cohen, & Dietz, 2009).

• Medical expenses paid by insurance companies or by 3rd party payors is $1429 more than for normal weight persons (Finkelstein et al., 2009).


Type 2 Diabetes Mellitus• Cause for CVD, strokes, renal failure,

non-traumatic limb amputations, & blindness; 7th cause of death (ADA, 2011)

• 2010 – 25.6 million adults (11.3%) dx w/ DM; w/ 1.9 million newly dx’d

• 2007 – medical costs est. @ $174 billion (directly - $116 billion; indirectly - $58 billion)

• Medical expenses for pt. w/ DM are 2.3 x higher than non-DM (CDC, 2011)


Bariatric Surgery• IDF taskforce reviewed role of bariatric surgery in

treatment & prevention of T2DM (Dixon et al., 2011)

• IDF bariatric surgery is effective, safe, & cost-effective for treating T2DM w/ people w/ BMI >35kg/m2, & treatment targets have not been met w/ medical regimens (TLC & meds)

• Avg cost of bariatric surgery over $13 000 w/ add’l costs for follow up care (Chang et al.,2011)

• Cost-effectiveness ratio less than $4000 per QALY• T2DM Improved &/or resolved• Decrease anti-DM med use (Makary et al., 2010)

• Maintained wt loss, improved lifestyle, & reduced mortality


Barriers in Using Bariatric Surgery

• Provider and patient perception and attitudes of obesity and bariatric surgery

• Cost and insurance coverage of bariatric surgery

• Accessibility

• Fear of complications and risks

• Lack of follow up care (adherence)(Reddy, 2009)


Types of Bariatric Surgery Gastric Bypass

Gastric Banding


MethodsDatabases

• Cochrane Database of Systematic Reviews

• Cochrane Central Register of Controlled Trials

• Cochrane Methodology Register

• MEDLINE/PubMed• CINHAL • Academic Search

Premier• PsychINFO

Search Terms Used

• Bariatric surgery• Obesity• Diabetes• Weight loss

Search Limitations• Pub. 2006-2011• English language• Accessible thru

UCF library or online as full-text or thru interlibrary loan


MethodsInclusion Criteria

• Adults ages 19 and above with a BMI > 35kg/m2

• Dx w/ T2DM or glucose intolerance or insulin resistance

• Compared gastric bypass or roux-en-Y gastric bypass to gastric banding or laparoscopic gastric banding

• Evidence Level I-V

Exclusion Criteria

• Obese pediatric populations

• BMI between 25-35kg/m2• Obese pregnant women • Single-arm studies

(bypass or banding) • Study compared either

bypass or banding with another bariatric surgery (eg. sleeve gastrectomy or biliopancreatic diversion/duodenal switch


Methods: Articles & Levels of Evidence

• 6 articles total in Literature Review

• 2 Systematic Reviews (Level V)

– Buchwald et al. (2009)

– Tice et al. (2008)

• 4 Cohort Studies (Level IV)

– Ballantyne et al. (2009)

– Gan et al. (2007)

– Lee et al. (2008)– Parikh et al. (2007) (Melynk & Fineout-Overholt, 2011)


Findings: Improved Blood Glucose Control • Gastric bypass showed greater reduction in BG &

HbA1c than banding; but no consistent significant difference between procedures (Ballantyne et al., 2008; Gan

et al., 2007; Lee et al., 2008).

• Lee et al. (2008) - @ 2 yr Post-Op lower BG was significantly statistically (p=0.006), but lower HbA1c did not show significance in both surgeries (p=0.938).

• Gan et al. (2007) - @13 mo. average no significant difference between surgeries in reduction of HbA1c but decrease was significant in overall DM control even though bypass mean of HbA1c=6.4% & 7.4% w/ banding (p<0.001) @ 13 mo ff up.


Findings: Diabetes Resolution

• Tice et al. (2008) – 6/14 studies; – Bypass: 72-100% of pts. had resolution T2DM – Banding: 47-77% within 1st few yrs Post-Op; – Bypass performed better w/ treating T2DM w/

absolute difference = 25% & NNT=4.

• Buchwald et al. (2009) - @ 2 yr Post-Op: % of pts had DM resolution– Bypass= 80% & Banding= 57%.


Findings: Increased Insulin Sensitivity & Decreased Insulin Resistance

• Ballantyne et al. (2009) & Lee et al. (2008), agreed bariatric surgery was effective in improving insulin resistance as evidenced by a drop in HOMA-I, but gastric bypass was more superior w/ respects to a consistent decrease in HOMA-I over time & maintained it (p=0.002).

• The gastric banding showed a rapid decrease of HOMA-I in 1st mo. post-op but had rebound effect @ 3rd mo., but decreased @ 6th mo. & maintained it thereafter (Lee, 2008).


Findings: Reduction in DM Med Use• @ Avg.13 mo Post-Op

– 39 pts. w/ Bypass – 27 D/C’d ALL meds; 11 used fewer meds; & 1 had no change in amt of med use (p<0.0001).

– 12 pts. Banding – 2 D/C’d ALL meds; 4 used fewer meds; 6 pts. Used same amt of meds (p<0.0001).

• 32 pts. on insulin pre-op, but post-op only 8 were still required to use insulin.

• 7/8 needed lower insulin doses, while 1 still cont. on same amt.

(Gan et al., 2007)


Findings: Reduction in DM Med Use (2)• Comparing LAGB & RYGB there’s NO significant

difference in rate of DM resolution w/ reduction in DM med use (p=0.12 for oral hypoglycemics & p=0.72 for insulin).

• @ 2 yrs post-op w/ bypass

13% pts use oral med (p=0.33);

13% use insulin (p=0.99).

• @ 2 yrs post-op w/ banding

34% pts. use oral med (p=0.10);

18% use insulin (p=0.99)

(Parikh et al., 2007)


Limitations & Gaps• Most studies were Cohort, Retrospective & Not

RCT’s• Selection Bias (Female = bypass; Male = banding)• Buchwald et al. (2009) had only 4.7% of studies

were RCTs, with only 1.6% actual level I evidence.• Tice et al. (2008) - all studies in review were cohort

or retrospective, except for one was RCT.• Parik et al. (2007) - didn’t have adequate HbA1c

data pre-op & post-op to perform statistical analysis on determining resolution of DM & small sample size

• Gan et al. (2007) was a very small sample size


Recommendations• Provider Awareness on options & accessibility• Screening for potential candidates for bariatric surgery• Psych support/behavior therapy pre- & post -op • Pt. Ed. on risks & benefits of different types of bariatric

surgery in order to make an informed decision.• Pt. Ed. on adherence to diet, exercise, & lifestyle

changes• Adequate ff. up w/ nutritionist, exercise physiologist, &

psychologist, surgeon & primary HCP• More research needed for those whose BMI is 30-

35kg/m2 w/ risks; obese elderly; obese adolescents; & new bariatric surgeries eg. Sleeve gastrectomy & biliopancreatic diversion /duodenal switch.


Conclusion• Obesity & T2DM are a multi-billion, multi-factorial

epidemic in U.S. that needs to be treated.• Initial txt should be focused on TLC (diet, exercise,

psych therapy & meds).• If unsuccessful w/ conventional txt, then consider

bariatric surgery, if BMI>35kg/m2 & w/ comorbidities.• Pt. ed. & ongoing care must be multidisciplinary.• Accd’g to review, in general, bariatric sx IS significant in

resolution of DM, but NO consistent statistical significant difference between bypass & banding.

• Gastric bypass does show a more rapid improvement of bld. sugar control, increase insulin sensitivity & reduction of med. use than gastric banding & therefore is preferred method for txt of obesity related T2DM.


Questions?

the effect of bariatric surgery on type 2 diabetes mellitus gastric bypass versus gastric banding an...

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