Is surgery better? Jordan Kautz, MS IV A b atory are C erence, an UNC-CH School of Medicine

Transcription

1 Is surgery better? Bariatric surgery versus medical management in type 2 diabetes mellitus Jordan Kautz, MS IV Ambulatory Care Conference, Jan 08 UNC-CH School of Medicine

2 For the soon-to-be medical resident LUKE SKYWALKER: Is the dark side stronger? YODA: No, no, no. Quicker, easier, more seductive. Empire Strikes Back (1980)

3 Quasi-hypothetical case Mr. A, 48-year-old male, pmhx significant for htn, hyperlipidemia, dm, and obesity (BMI 35) presents for diabetes f/u. DM dx d 03. Tried diet, exercise. +Metformin. +Glipizide. Most recent A1c 8.6% despite optimal mgmt. Add third agent? Insulin? Other ideas? Doc, what about that weight loss surgery? In addition to weight loss (and perhaps as a result), what health benefits accrue secondary to bariatric surgery for such a patient?

4 Another quasi-hypothetical case Mrs. B, 35-year-old female, pmhx significant only for obesity (BMI 39), presents c new dx type 2 dm. Battling wt since college. Not started any meds. Baseline A1c 7.8%. Father c dm, on insulin, good control. Sister underwent gastric banding, good result. Recommendations? I heard on the news gastric banding can cure diabetes if done early is that right? For new diagnosis type 2 dm patients (preserved pancreatic beta-cell function), is there recovery from diabetes and might it be clinically significant?

5 Med Student Reasoning Twin public health epidemics Not all diabetics are obese and not all obese persons have diabetes, but DIABESITY?!?! Early and intensive treatment of diabetes improves health outcomes, quality of life Weight loss improves blood glucose control, morbidity and mortality Bariatric surgery leads to greater weight loss than therapeutic lifestyle change (in most cases but not without assuming greater risks) Observational studies suggest that surgically induced weight loss may be an effective treatment for type 2 diabetes mellitus, especially proximally

6 What & How it (might) work (we think) Not talking about one procedure Laparoscopic adjustable gastric banding (LAGB), roux-en-y, biliary-pancreatic diversion i Each procedure involves different risks, benefits, and metabolic consequences Purely a secondary outcome of surgically-induced wt loss Foregut hypothesis: Improved diabetic control by excluding the duodenum and proximal jejunum from nutrient flow Hindgut hypothesis: More rapid delivery of nutrients to distal intestine results in improved glucose metabolism (via GLP-1, other peptides) Questions re: safety, invasiveness, cost-effectiveness Underrepresented as treatment option in ADA guidelines, recommendations by similar bodies

7 First RCT hot off the press Dixon JB, O Brien PE, Playfair J, et al. Adjustable gastric banding and conventional therapy for type 2 diabetes: A randomized controlled trial. JAMA 2008; 299(3): PICO: For adults, age 20-60, BMI 30-40, and T2DM dx d w/i two yrs, does LAGB compared to wt loss by lifestyle l change lead to increased remission of type 2 diabetes (FPG<126, A1c <6.2%, no glycemic gy rx)?

8 Study Population (n=60) Inclusion: Age 20-60, BMI 30-40, Dx d c T2DM w/i 2yrs and NO evidence of renal impairment, diabetic retinopathy Exclusion: T1DM, DM secondary to specific dz, previous bariatric surgery, h/o mental impairment, drug or EtOH addiction, recent major vascular event, internal malignancy, portal HTN

9 Study Design Run-in to maximize current mgmt and assess compliance NON-blinded computer randomization Table 1: appears successful Conventional treatment: GP, dietitian, nurse, diabetes educator visit c at least 1 team member q6wks during 2yrs; diet & physical activity requirements Not treated according to standardized algorithm optimal (?) management Surgical program: ALL aspects of conventional rx PLUS LAGB; progress reviewed by bariatric surgery team q4-6wks; adjustments to band volume using standard clinical criteria Highly experienced, specialized surgical group reproducible (?) success

10 Study Metrics Primary: Proportion of patients achieving remission i (as previously defined) d) Secondary: % change in A1c, wt, bp, waist circumference, lipids, id change in medication use, proportion of pts c metabolic syndrome, change in direct measures of insulin resistance

11 Results Diabetes remission: 73% (surgical) versus 13% (medical), p< Greater percentage of wt loss at two yrs and lower baseline A1c values were independently associated with remission Percentage of weight loss explained most of the variance 20% (surgical) versus 1.4% (medical), p<0.001

12 Primary and Secondary Outcomes at 2 Years STATISTICALLY significant improvements in secondary end points though the study was NOT powered to assess multiple outcome measures Adverse events (surgical group) included superficial wound infection, gastric pouch enlargement requiring nonurgent revision, and band removal Minor events (surgical group) included postop fever, hypoglycemic episode, and GI intolerance to metformin

13 Limitations Restricted to recent diagnosis diabetes Results may not apply to those with longer hx of dz due to deterioration of beta-cell fxn Sample size and duration of follow-up More diverse population and longer f/u to see if benefits persist, evaluate hard end points

14 Ladies first Based on this study, its strengths and limitations, it ti what would you say to Mrs. B? What in the literature or about the patient would be persuasive in recommending LAGB? Should the bariatric surgeon be on speed dial for all newly diagnosed diabetics when diet and exercise fail?

15 Swedish Obese Subjects (SOS) Study design: Prospective, nonrandomized intervention trial (2y n=4,047; 10y n=1,703) Intervention: Fixed or variable banding, vertical banded gastroplasty, gastric bypass compared to customary treatment (non-standardized including no treatment) Subjects: Obese subjects who underwent gastric surgery and contemporaneously matched, conventionally treated obese control subjects Inclusion: BMI>34 (M), >38 (F), Age Exclusion: Not well detailed, available elsewhere

16 And the winners are TWO YEARS -23.4% (surgical) +0.1% (control) TEN YEARS -16.1% (surgical) +1.6% (control)

17 Effect on incidence of and recovery from risk conditions (1)

18 Effect on incidence of and recovery from risk conditions (2)

19 Questions What biologically plausible mechanism might account tfor more successful recovery from than incidence of hypertension, dyslipidemia? Does dichotomizing variables (or interventions for that matter) obscure information that may be meaningful for clinical practice? Patient health outcomes?

20 Getting back to the other guy Based on this study, its strengths and limitations, it ti what would you say to Mr. A? Is a disease-free interval likely to pay dividends id d for this gentleman years later (when we know micro- and macro-vascular complications operate on such a time scale)? Yeah, well, but what if he just looks and feels great?

21 References Dixon JB, O Brien PE, Playfair J, et al. Adjustable gastric banding and conventional therapy for type 2 diabetes: A randomized controlled trial. JAMA 2008; 299(3): Sjostrom L, Lindroos AK, Peltonen M, et al. Lifestyle, diabetes, and cardiovascular risk factors 10 years after bariatric surgery. NEJM 2004; 351(26): Buchwald H, Avidor Y, Braunwald E, et al. Bariatric surgery: a systematic review and meta-analysis. JAMA 2004; 292(14): Ferchak CV and Meneghini LF. Obesity, bariatric surgery, and type 2 diabetes a systematic review. Diabetes Metab Res Rev 2004; 20(6): Dixon JB, Pories WJ, O Brien PE, et al. Surgery as an effective early intervention for diabesity: why the reluctance? Diabetes Care 2005; 28(2):472-4 Chapman AE, Kiroff G, Game P. LAGB in the treatment of obesity: a systematic literature review. Surgery 2004; 135: PubMed search bariatric surgery [MeSH] AND diabetes mellitus, type 2 [MeSH], limits: English (134 articles)