Costeffectiveness of Gastric Bypass Surgery for Morbidly Obese Patients

1
Cost-effectiveness of Gastric Bypass Surgery for
Morbidly Obese Patients

• HCMG 901
• December 8, 2005
• Ben Shiller
• Terry White

2
The obesity epidemic is getting worse

• In 2002, 5.1 of U.S. adults had body mass index
  (BMI) higher than 40
• BMI (weight in kg) / (height in meters)2
• Prevalence of BMI 40 increased by 4x from 1986
  to 2000
• Prevalence of BMI 50 increased by 5x during
  this period

3
Obesity is associated with adverse health
conditions

• Hypertension
• Hypercholesterolemia
• Type 2 diabetes
• Coronary heart disease
• Stroke
• Gallbladder disease
• Osteoarthritis
• Sleep apnea and respiratory problems
• Some cancers (e.g., endometrial, breast, colon)

Source http//www.cdc.gov/nccdphp/dnpa/obesity/co
nsequences.htm
4
Obesity is associated with early death

• An estimated 300,000 deaths per year may be
  attributed to obesity
• Even moderate weight excess (10 to 20 pounds for
  a person of average height) increases the risk of
  death, particularly among adults aged 30 to 64
  years
• Individuals who are obese (BMI 30) have a 50 to
  100 increased risk of premature death from all
  causes, compared to individuals with a healthy
  weight

Source http//www.surgeongeneral.gov/topics/obesi
ty/calltoaction/fact_consequences.htm
5
Losing weight through diet and exercise is rarely
successful . . . and worthy of prime-time TV
The Biggest Loser
6
While most therapies for weight loss fail . . .
gastric bypass surgery is very effective
Sjostrom L, Lindroos AK, Peltonen M, et al.
Lifestyle, diabetes, and cardiovascular risk
factors 10 years after bariatric surgery. N Eng J
Med 20043512683-93.
7
Gastric bypass surgery changes the way you eat
and digest food

• Limits food intake by dividing stomach to form
  small pouch induces malabsorption by bypassing
  proximal jejunum

8
Bariatric surgery is booming
Santry HP, Gillen DL, Lauderdale DS. JAMA
2005294(15)1909-17.
9
Gastric bypass surgery is costly

• Cost of surgery is more than 20,000
• Further costs are incurred due to complications,
  additional surgery, and long-term follow-up
• Significant indirect costs (e.g., lost work-time)

Livingston EH. Am J Surg 2005190816-20.
10

• Gastric bypass surgery is effective and
• costly, but is it cost-effective?

11
Methods

• Morbid obesity (BMI 40 - 55)
• Age 25-50
• History of failed attempts at weight-loss with
  non-surgical therapies
• Exclusion criteria include smoking and
  significant co-morbidities, consistent with
  clinical guidelines
• Two arms Gastric bypass versus no treatment
• Cost surgery lifetime expected health care
  costs for conditions related to obesity
• Outcome quality-adjusted life-years (QALYs)
• CER determined by dividing difference in total
  lifetime medical cost by difference in QALYs

12
Pathway
BMI 40-50
Surgery
No Surgery
Revisional Surgery
Reversal Surgery
Successful
Death
Obese
13
Cost variables associated with procedure,
recovery, and future health status

• Pre-operative evaluation
• Surgical procedure
• Hospital stay
• Follow-up out-patient visits
• Complications and additional surgery
• Life-time expected medical costs due to
  obesity-related diseases (at lower BMI for
  successful cases, and pre-op BMI for unsuccessful
  cases)

14
Complications

• Death
• Deep vein thrombosis
• Pulmonary embolism
• Wound infection
• Incisional hernia
• Intractable dumping syndrome
• Staple line disruption
• Dehiscence
• Gallstones
• Revision Surgery
• Reversal Surgery

15
Measurement of QALYs

• Health State Hospitalization
  Recovery Period of rapid weight-loss
  Steady-state

Quality of Life A
B C
D or E
Example of calculation of days spent in each state
QALYs (Total Days in Hospital)(A) (Total Days
in Recovery) . . .
16
QALY weights to be determined by survey

• Survey will be completed during each of the three
  postoperative states (hospitalization, recovery,
  rapid weight loss)
• Patients will rate themselves using questions
  from the HUI index. The mobility, emotion,
  self-care, and pain attributes will be included
  in the survey. This will determine the QALY
  weight for a given health state.

17
Results of study

• Cost-effectiveness ratio
• Cost (Gastric Bypass) Cost (No treatment)
• QALY (Gastric Bypass) QALY (No treatment)