The Effect of Bariatric Surgery on Type 2 Diabetes Mellitus Gastric Bypass versus Gastric Banding An Integrative Literature Review Mary Jane Concengco, BSN, RN, NP Resident

University of Central Florida Research Question In morbidly obese adults with type 2 diabetes mellitus, does gastric bypass improve or resolve diabetes better than gastric banding?

University of Central Florida Background & Significance In % 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)

University of Central Florida Obesity Increased risk for development of HTN, CVD, strokes, CA, hyperlipidemia, & T2DM (NHLBI, 1998). In Medical costs for obesity related conditions $147 billion (Finkelstein, Trogdon, Cohen, & Dietz, 2009). Medical expenses paid by insurance companies or by 3 rd party payors is $1429 more than for normal weight persons (Finkelstein et al., 2009).

University of Central Florida 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 $174 billion (directly - $116 billion; indirectly - $58 billion) Medical expenses for pt. w/ DM are 2.3 x higher than non-DM (CDC, 2011)

University of Central Florida 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 $ 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

University of Central Florida 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)

University of Central Florida Types of Bariatric Surgery Gastric Bypass Gastric Banding

University of Central Florida Methods Databases 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 English language Accessible thru UCF library or online as full-text or thru interlibrary loan

University of Central Florida Methods Inclusion 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

University of Central Florida 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)

University of Central Florida 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) 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 13 mo ff up.

University of Central Florida Findings: Diabetes Resolution Tice et al. (2008) – 6/14 studies; –Bypass: % of pts. had resolution T2DM –Banding: 47-77% within 1 st 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%.

University of Central Florida 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 3rd mo., but 6th mo. & maintained it thereafter (Lee, 2008).

University of Central Florida Findings: Reduction in DM Med 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)

University of Central Florida 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 2 yrs post-op w/ bypass 13% pts use oral med (p=0.33); 13% use insulin 2 yrs post-op w/ banding 34% pts. use oral med (p=0.10); 18% use insulin (p=0.99) (Parikh et al., 2007)

University of Central Florida 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

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

University of Central Florida 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.

University of Central Florida Questions?