Economic Impact of the Clinical Benefits of Bariatric Surgery in Morbidly Obese Patients with Diabetes: An Observational Study

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Economic Impact of the Clinical Benefits of Bariatric Surgery in Morbidly Obese Patients with Diabetes: An Observational Study

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Economic Impact of the Clinical Benefits of Bariatric Surgery in Morbidly Obese Patients with Diabetes: An Observational Study Samuel Klein, M.D.;1 Arindam Ghosh, PhD ... – PowerPoint PPT presentation

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Title: Economic Impact of the Clinical Benefits of Bariatric Surgery in Morbidly Obese Patients with Diabetes: An Observational Study


1
Economic 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2010 Preliminary Do Not Cite Without Permission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
2
Disclaimer
  • 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.

3
Background
  • 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

4
Effect of Bariatric Surgery on Comorbidities
5
Effect of Bariatric Surgery on Comorbidities
6
Effect of Bariatric Surgery on Comorbidities
7
Effect of Bariatric Surgery on Comorbidities
8
Objective
  • 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

9
Data 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

10
Methods
11
Sample 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.
12
Identifying 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
13
Matching 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

14
Methods 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

15
Calculating 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

16
Outcome 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

17
Results
18
Results Baseline Comorbidities (Patients vs.
Controls 6 months prior to surgery date)
Significant at the 95 level
19
Results 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.
20
Results 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

21
Results RoI to Bariatric Surgery for U.S.
Diabetes Population, Multivariate Analysis (Mean
and 95 Percent Confidence Interval)
22
Results 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.
23
Diagnostic Claims for Diabetes(Diabetes
Diagnosis)
24
Trend of Diabetes Medication Claims(Prescription
Fill)
25
Trend of Diabetes Medication ClaimsPre-Index
Insulin Claimants

26
Trend of Diabetes Medication ClaimsPre-Index
Non-Insulin Medication Claimants
27
Adjusted Diabetes Medication and Supply Costs
28
Conclusions
29
Conclusion 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.

30
Conclusion 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.

31
Conclusions
  • 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.

32
References
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    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
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  • 6. Wing RR, Koeske R, Epstein LH, Nowalk MP,
    Gooding W, Becker D. Long-term effects of modest
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    Intern Med 19871471749-1753.
  • 7. Pories WJ, Swanson MS, MacDonald KG, Long SB,
    Morris PG, Brown BM, Barakat HA, deRamon RA,
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33
  • Pierre Cremieux
  • Managing Principal
  • Analysis Group, Inc.
  • 111 Huntington Avenue
  • Boston, MA 02199
  • 617-425-8135
  • pcremieux_at_analysisgroup.com
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