Title: Economic Impact of the Clinical Benefits of Bariatric Surgery in Morbidly Obese Patients with Diabetes: An Observational Study
1Economic Impact of the Clinical Benefits of
Bariatric Surgery in Morbidly Obese Patients with
Diabetes An Observational Study
- Samuel Klein, M.D.1 Arindam Ghosh, PhD2
Pierre-Yves Cremieux, PhD2,3 Sara Eapen, PhD2
Tamara J. McGavock, BA2 - 1 Center for Human Nutrition, Washington
University School of Medicine in St. Louis - 2 Analysis Group, Inc., Boston, Massachusetts,
USA - 3 Université du Québec à Montréal, Montréal,
Québec, Canada -
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Prepared for First Canadian Summit on Metabolic
Surgery for Type II Diabetes May 7,
2010 Preliminary Do Not Cite Without Permission
from Authors
2Disclaimer
- Sponsored study funded by Ethicon Endo-Surgery,
Inc - Ethicon Endo-Surgery, Inc. has no independent
knowledge concerning the information contained in
this article, and findings and conclusions
expressed are those reached by the authors - This presentation is the work of the author and
may not necessarily reflect the views of Ethicon
Endo-Surgery, Inc.
3Background
- In 2007, the prevalence rate of diabetes in the
US was 7.8, affecting 12 million men and 11.5
million women1 - Estimated yearly costs of managing a diabetes
patient (13,243) are more than five times that
of a patient without diabetes (2,560)2 - The estimated annual total economic cost of
diabetes in the US was 174 billion in 2007
116 billion in medical expenditures and 58
billion in reduced productivity - Obesity is a major risk factor for type II
diabetes,3 and the risk of diabetes increases
directly with body mass index (BMI)4 - Diabetes-related costs represent a
disproportionate share of healthcare costs among
the obese5 - Weight loss is an important therapeutic goal in
obese patients with type II diabetes, because
even moderate weight loss (5) improves insulin
sensitivity6 - Bariatric surgery is the most effective weight
loss therapy and has considerable beneficial
effects on diabetes7,8,9
4Effect of Bariatric Surgery on Comorbidities
5Effect of Bariatric Surgery on Comorbidities
6Effect of Bariatric Surgery on Comorbidities
7Effect of Bariatric Surgery on Comorbidities
8Objective
- To estimate the economic impact of the clinical
benefits of bariatric surgery on medical costs
and return on investment (RoI) of the surgery in
morbidly obese diabetes patients
9Data Source
- De-identified health insurance and disability
claims from approximately 8.5 million employees,
spouses, and dependents from 40 large companies
throughout the U.S. - Time period covered January 1, 1999 - December
31, 2007 - The database includes
- Outpatient medical services (including diagnoses
and procedures) - Inpatient medical services (including diagnoses
and procedures) - Outpatient prescription drug dispensing records
- Demographics
- Enrollment history
- Billed charges
- Insurance payments
10Methods
11Sample Selection
- Patients with diabetes at baseline, were
identified using the following criteria - At least one bariatric surgery claim (HCPCS
codes 43770, 43644, 43645, 43845, 43846, 43847,
43842, 43843, S2085, S2082, S2083) for surgery
patients. No bariatric surgery claim for control
patients - The date of the first such claim was identified
as the date of surgery (index date) - At least one medical claim with the diagnosis of
morbid obesity (ICD-9-CM 278.01) anytime prior
to index date - At least six months of continuous enrollment
prior to the initial date of index and one month
following - Age between 18 and 65 as of the index date
- Diabetes diagnosis prior to index date
For surgery eligible controls, the index date
is their matched patient surgery date. The
average patient length in the sample was 18
months.
12Identifying Patients with Diabetes
- Following Pladevall et al.,10 patients were
classified as having diabetes if both of these
were true in the months five through two prior to
index date - 1 medical claim for any of these conditions
- Diabetes (ICD-9-CM 250.xx)
- Dyslipidemia (ICD-9-CM 272.xx)
- Hypertension (ICD-9-CM 401.xx-405.xx)
- 1 drug claim for anti-diabetic medications
Includes type I and II diabetes
13Matching Diabetic Surgery and Control Patients
- Each diabetic surgery patient was matched to a
diabetic control on the following
socio-demographic and comorbid characteristics - Age group (18-30, 31-40, 41-50, and 51-60) as of
index date - Gender
- Other Comorbidities (Asthma, Coronary Artery
Disease, Gall Stones, Gastroesophageal Reflux,
NASH/NAFLD, Sleep Apnea, Urinary Incontinence) - State of residence
- 5-month pre-surgery direct costs (excluding month
prior to index date) - In case of multiple matches, we randomly selected
one
14Methods Calculation of ROI
- The cost associated with bariatric surgery
(investment) is estimated from the incremental
costs incurred during the surgery hospital stay,
and, typically, in the month prior to the
surgery, and the two months after surgery - Cost savings from bariatric surgery are
calculated as the difference in direct costs
between bariatric surgery patients and their
controls - The ROI is the ratio of cost savings to the
initial surgery investment cost - Both the cost associated with bariatric surgery
and the associated cost savings are estimated
using a multivariate analysis - Monthly medical costs were normalized to December
2008 dollar value by first deflating by the
CPI-MC (medical care consumer price index) and
discounting by the 3-month T-bill rate of 3.22
15Calculating an ROI (contd.)
- The normalized monthly costs were regressed
(using a Tobit model with cluster option) on an
indicator variable for bariatric surgery
interacted with a number of time indicator
variables - Three to Six Months Prior to Surgery Month Prior
to Surgery Time of Surgery Two Months Post
Surgery Three to Six Months Post Surgery Seven
to Twelve Months Post Surgery Thirteen to
Eighteen Months Post Surgery Nineteen to
Twenty-Four Months Post Surgery Twenty-Five
Months or More Post Surgery - Additionally, the multivariate model also
controls for - Age
- A number of comorbidities which were not used for
matching in the first step including breast
cancer, congestive heart failure, lymphedema,
major depression, osteoarthritis, polycystic
ovary syndrome, pseudo tumor cerebri, and venous
stasis/leg ulcers
16Outcome Measures
- Three outcome measures were compared between
diabetic surgery and control patients post index
date - Total medical costs
- Diagnostic claims for diabetes, where diabetes is
defined using the definition in Pladevall et al. - Trend in diabetes diagnostic claims was
calculated using the percentage of available
patients satisfying the diabetes definition post
index - Frequency and pattern of use of anti-diabetic
medication - Non-Insulin medications including Sulfonylureas,
Biguanides, Alpha-Glucosidase Inhibitors,
Meglitinides, Thiazolidinediones, DPP-4
Inhibitors, Incretin Mimetics, Synthetic Amylin
Analogs - Insulin medications
- Adjusted average total anti-diabetic drug costs
including supplies post index date - Calculated as the total of the amounts covered by
both insurance and co-pay for each prescription
fill - Outcomes between surgery and control patients
were compared using chi squared tests for
categorical measures and Wilcoxon rank sum tests
for continuous measures
17Results
18Results Baseline Comorbidities (Patients vs.
Controls 6 months prior to surgery date)
Significant at the 95 level
19Results Baseline Health Care Utilization and
Costs (Patients vs. Controls 6 months prior to
surgery date)
Significant at the 95 level Cost are calculated
based on months -6 to -2.
20Results ROI to Bariatric Surgery, Multivariate
Analysis1
- The multivariate model controls for age, gender,
and the following comorbidities breast cancer,
congestive heart failure, lymphedema, major
depression, osteoarthritis, polycystic ovary
syndrome, pseudo tumor cerebri, and venous
stasis/leg ulcers. - There are no procedure codes that break out
laparoscopic surgery until 2004. - Significant at the 5 level
21Results RoI to Bariatric Surgery for U.S.
Diabetes Population, Multivariate Analysis (Mean
and 95 Percent Confidence Interval)
22Results ROI to Bariatric Surgery, All Patients
Total Direct Medical Costs in December 2008
dollars. Inflated to 2008 dollars using CPI-MC
(medical care consumer price index) and grown at
a rate of 3.22.
23Diagnostic Claims for Diabetes(Diabetes
Diagnosis)
24Trend of Diabetes Medication Claims(Prescription
Fill)
25Trend of Diabetes Medication ClaimsPre-Index
Insulin Claimants
26Trend of Diabetes Medication ClaimsPre-Index
Non-Insulin Medication Claimants
27Adjusted Diabetes Medication and Supply Costs
28Conclusions
29Conclusion on Economic Outcomes
- The initial investment averaged approximately
25,000 for all surgeries 1999-2007, 31,000 for
open surgeries 1999-2003, 29,000 for open
surgeries 2004-2007, and 19,000 for laparoscopic
surgeries 2004-2007. - When the comorbidities and demographic factors
are controlled for, initial investment is
returned within - 30 months for patients who undergo any type of
bariatric surgery. - 29 months for patients who undergo open surgery.
- 26 months for patients who undergo laparoscopic
surgery. - Cost savings associated with surgery started
accruing at month 3.
30Conclusion on Clinical Benefit Outcomes
- For diagnostic claims of diabetes, by the first
three-month period after surgery, 40.7 of
surgery patients had a diabetes related claim
compared to 72.1 of control patients (plt.001). - By month 6, only 28.2 of surgery patients
reported a claim of diabetes versus 73.5 of
control patients (plt.001) - By the first three-month period post-index, 45.6
of surgery patients had filled a prescription for
diabetes medication in the previous 3 months,
compared to 90.8 of control patients. - At month 6, the percentages were 33.5 and 89.7,
respectively (plt.001). - Among patients who had insulin claims prior to
index date, insulin claims dropped to 42.8 for
surgery patients and remained at 92.4 for
control patients at month 3 after index (plt.001).
- Among surgery patients who had claims for
non-insulin diabetes medications prior to
surgery, 37.3 had claims for non-insulin
medications at month 3, compared with 86.3 of
control patients (plt.001). - 84.5 of surgery patients who had claims for
non-insulin medication at index had no claims for
any diabetes medications by month 36. - By the first three-month period after index, the
average total cost of diabetes medications and
supplies for surgery patients was 33, compared
to 123 for control patients.
31Conclusions
- Bariatric surgery has a large, statistically
significant and sustained positive effect on
diabetes within six months, in obese patients. - Surgery patients appear to have resolution or
more durable control of their diabetes compared
to controls, as evidenced by their switching
patterns of anti-diabetic medications, post index
date. - The results of this study demonstrate that the
clinical benefits of bariatric surgery in
morbidly obese diabetes patients translate into
considerable economic benefits. - These data indicate that surgical therapy is
clinically more effective and ultimately less
expensive than standard therapy for morbidly
obese diabetes patients.
32References
- 1. National diabetes fact sheet United States,
2007. CDC Diabetes. 2007. - 2. Campbell RK, Martin TM. The chronic burden of
diabetes. Am J Manag Care. 200915S248-S254 . - 3. Ford ES, Williamson DF, Liu S. Weight changes
and diabetes incidence findings from a national
cohort of US adults. Am J Epidemiology
1997146214-222. - 4. Colditz GA, Willett WC, Rotnitzky A, Manson
JE. Weight gain as a risk factor for clinical
diabetes mellitus in women. Ann Intern Med
1995122481-486. - 5. Cawley, J, Rizzo, J, Gunnarsson, C, Haas, K.
The health care cost effects of diabetes among
obese and morbidly obese adults in the United
States. Poster presented at International Society
of Pharmacoeconomic Outcomes Research (ISPOR)
13th Annual International meeting. Toronto, ON,
Canada. - 6. Wing RR, Koeske R, Epstein LH, Nowalk MP,
Gooding W, Becker D. Long-term effects of modest
weight loss in type II diabetic patients. Arch
Intern Med 19871471749-1753. - 7. Pories WJ, Swanson MS, MacDonald KG, Long SB,
Morris PG, Brown BM, Barakat HA, deRamon RA,
Israel G, Dolezal JM, Dohm L. Who would have
thought it? An operation proves to be the most
effective therapy for adult-onset diabetes
mellitus. Ann Surg 1995222(3)339-352. - 8. Dixon JB, OBrien PE, Playfair J, Chapman L,
Schachter LM, Skinner S, Proietto J, Bailey M,
Anderson M. Adjustable gastric banding and
conventional therapy for type 2 diabetes. JAMA
2008 299(3)316-323. - 9. Schauer PR, Ikramuddin S, Gourash W,
Ramanathan R, Luketich J. Outcomes of
laparoscopic roux-en-Y gastric bypass for morbid
obesity. Ann Surg 2000232(4)515-529. - 10. Pladevall M, Williams LK, Potts LA, Divine G,
Xi H, Lafata JE. Clinical Outcomes and Adherence
to Medications Measured by Claims Data in
Patients With Diabetes. Diabetes Care, 2004, Vol
27 Part 12, pages 2800-2805.
33- Pierre Cremieux
- Managing Principal
- Analysis Group, Inc.
- 111 Huntington Avenue
- Boston, MA 02199
- 617-425-8135
- pcremieux_at_analysisgroup.com