Aubert, RE

Epstein, RS

Frueh, FW

Stanek, EJ

Teagarden, JR

Yao, J

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CV3 THE IMPACT OF PROTON PUMP INHIBITORS ON CARDIOVASCULARRELATED EVENT COSTS IN PATIENTS INITIATING CLOPIDOGREL 

Abstracts A7
year, pharmacy charges, sales tax, patient compliance, patient co-payments, hospital 
discount, hospital pharmacy costs, therapeutic drug monitoring (TDM), and wastage.
A descriptive analysis of the frequency of reporting of the extracted data was per-
formed. RESULTS: The dates and sources of drug costs were speciﬁ ed in the majority 
of cases (53 and 50 of 59 studies, respectively), but details of the routes of administra-
tion were absent from 39 studies. The source of drug costs was referenced in 48 
studies. A minority of studies considered pharmacy charges(3), sales taxes(5), hospital 
discounts(3) or patient co-payments(1). The costs of TDM were reported in 2 out 
of 24 possible cases; and no evaluations accounted for costs associated with drug 
wastage. CONCLUSIONS: The costing of drugs in pharmacoeconomic studies is often
poorly reported and sometimes poorly conducted. Estimates based on readily available
list prices may not accurately reﬂ ect true costs to payers, and this may have a signiﬁ -
cant impact on estimates of cost-effectiveness. We propose recommendations for esti-
mating drug costs for use in future studies.
CO4
COMPARISON OF INPATIENT COST ESTIMATION METHODS: 
USING DATA FROM A CYSTIC FIBROSIS TRIAL
Dinan M1, Morgan Dewitt E2, Grussemeyer C1, Reed SD1
1Duke Clinical Research Institute, Durham, NC, USA, 2Duke University, Durham, NC, USA
Inpatient costs are often assigned using reimbursement rates corresponding to diag-
nosis related groups (DRGs) or similar coding system. Other approaches to cost
assignment may provide more valid estimates. OBJECTIVE: To evaluate different
inpatient cost estimation methods utilizing data from the 2001–2005 National 
Inpatient Survey (NIS) applied to event-level data from a randomized trial of patients 
with cystic ﬁ brosis and to compare these approaches within the NIS sample. 
METHODS: Hospitalizations in a Phase 3 clinical trial were matched (1 : many) to 
NIS discharges representing cystic ﬁ brosis patients based on ICD-9 diagnostic and 
surgical procedure codes. Costs for hospitalizations in the trial were estimated using 
these NIS discharges applying six different methods; mean cost, median cost, mean 
daily cost, median daily cost, DRG-based costs, and regression analysis. Cost estima-
tion within the NIS sample was evaluated for each method by comparing root mean
squared error (RMSE) and mean absolute percent error (MAPE) between predicted
and actual discharge costs. RESULTS: All but two of the 98 hospital admissions from
the trial could be matched with 10 or more NIS discharges. Mean estimates of inpa-
tient costs in the trial ranged from $5,368 (SD  2,071) with the standard DRG 
method to $16,635 (SD  69,822) with the regression method. Of the six methods, 
median daily cost resulted in the smallest MAPE (51% o 11% SE) with a RMSE of 
12,597 within the NIS matched sample (N  8,485), followed by the mean daily cost
approach MAPE (60% o 13% SE) with a RMSE of 12,248 and regression analysis 
(69% o 12% SE). CONCLUSION: Different methods are available for estimating 
inpatient expenditures which may provide advantages over existing, more generalized
cost estimation procedures such as DRGs. Further evaluation of such methods is 
warranted to improve the validity of costs assigned to hospitalizations in studies of 
patients with serious underlying conditions.
PODIUM SESSION II: CARDIOVASCULAR DISORDERS – 
Outcomes Research Studies
CV1
ASSOCIATION OF CARDIOMETABOLIC RISK FACTORS AND
PREVALENT CARDIOVASCULAR EVENTS
Malone DC1, Boudreau D2, Nichols G3, Raebel MA4, Fishman P5, Feldstein A3, 
Ben-Joseph R6, Okamoto LJ7
1University of Arizona College of Pharmacy, Tucson, AZ, USA, 2United BioSource
Corporation, Seattle, WA, USA, 3Kaiser Permanente, Portland, OR, USA, 4Kaiser Permanente 
Colorado, Denver, CO, USA, 5Group Health, Seattle, WA, USA, 6Sanoﬁ -Aventis, Bridgewater, 
NJ, USA, 7United BioSource Corporation, Bethesda, MD, USA
OBJECTIVES: Although cardiovascular disease causes substantial morbidity and mor-
tality, how individual and groups of risk factors contribute to cardiovascular outcomes
is incompletely understood. This study evaluated cardiometabolic risk factors and
their relationship to prevalent diagnosis of acute myocardial infarction (AMI) and 
stroke. METHODS: We used retrospective data from three integrated health care 
systems that systematically collect and store detailed patient-level data. Adult enrollees
were eligible for inclusion if they had all of the following clinical measurements includ-
ing weight, height, blood pressure, high density lipoproteins, triglycerides, and fasting 
blood glucose or evidence of diabetes from July 1, 2003 to June 30, 2005. We used
National Cholesterol Education Program Adult Treatment Panel III guidelines to 
determine qualifying levels for cardiometabolic risk factors. RESULTS: A total of 
170,648 persons met the inclusion/exclusion criteria; 11,757 had no qualifying risk
factors, 25,684 had one, 38,176 had two, and 95,031 had three or more risk factors.
Compared to those without risk factors, persons with any one risk factor were 2.21
(95% CI: 1.78–2.74) times more likely to have had a diagnosis of AMI or stroke. The
risk increased to 2.79 (95% CI: 2.26–3.42) for persons with two, 3.45 (95% CI: 
2.80–4.24) for persons with three, 4.35 (95% CI: 3.54–5.35) for persons with four,
and 5.73 (95% CI: 4.65–7.07) for persons with ﬁ ve risk factors. The highest risk was 
conferred by having the combination of risk factors of diabetes, hypertension, and
dyslipidemia, with or without weight risk. CONCLUSIONS: This study demonstrates 
a direct association between an increasing number of cardiometabolic risk factors and 
prevalent diagnosis of AMI and stroke. The combination of risk factors conferring
highest risk was diabetes, hypertension, and dyslipidemia.
CV2
COMPARISON OF CARDIOVASCULAR EVENT RATES IN SUBJECTS
WITH TYPE-2 DIABETES MELLITUS WHO AUGMENTED FROM STATIN
MONOTHERAPY TO STATIN PLUS FIBRATE COMBINATION THERAPY 
WITH THOSE WHO REMAINED ON STATIN MONOTHERAPY
Suh HS, Doctor JN
University of Southern California, Los Angeles, CA, USA
OBJECTIVES: To compare cardiovascular-event (CV) rates in subjects with type II-
diabetes who augmented from short-term statin-monotherapy to statin  ﬁ brate com-
bination-therapy with those who remained on statin-monotherapy in a managed care 
setting. METHODS: “Combo-group” (deﬁ ned as subjects who used statin less than
six-months and augmented to statin plus ﬁ brate for more than six-months) and 
“mono-group” (deﬁ ned as subjects who used statin less than six-months and remained 
on statin for more than six-months) were identiﬁ ed among subjects with type-2 dia-
betes with 2-years intake-period (July 1, 2002-June 30, 2004) and three-years follow-
up using administrative claims from a Westcoast-based health plan in U.S. covering 
4million lives. Outcomes measure was any occurrence of CV including ischemic heart 
disease, cerebrovascular disease, and peripheral vascular disease. A multivariate logis-
tic model was developed to evaluate adjusted CV-risk. Multicollinearity test, model 
sensitivity, and speciﬁ city analyses were performed. RESULTS: Mean (/SD) age 
was 58(/11) years in combo-group(N  322) and 61(/11) years in mono-group 
(N  9955). In combo-group, mean(/SD) treatment-duration was 909(/409) days 
for statin plus ﬁ brate following 118(/52) days for statin-monotherapy. In mono-
group, mean(/SD) treatment-duration was 1339(/451) days for statin-monother-
apy following 115(/51) days for statin-monotherapy. Unadjusted CV-rates between
groups were not signiﬁ cantly different (odds ratio [OR]  0.93, P  0.496). Adjusting
for age, gender, prior CV, CV related pharmacy-costs, Elixhauser-comorbidity, and 
diabetes with complication, combo-group experienced 23% risk reduction in CV
compared with mono-group (OR  0.67, P  0.006). All covariates were signiﬁ cantly 
associated with CV-rates. The model did not suffer from multicollinearity and model 
sensitivity (71.8%) and speciﬁ city (76.6%) were satisfactory. CONCLUSIONS: In a 
managed care population with type-2 diabetes after adjusting for known baseline dif-
ferences, CV-risk was signiﬁ cantly lower among subjects who augmented from short-
term statin use to statin  ﬁ brate combination-therapy compared with those remained 
on statin-monotherapy. We hope this result will be useful in health policy to reduce 
CV-risk in diabetics. Future research is in progress to address the causality behind this
association.
CV3
THE IMPACT OF PROTON PUMP INHIBITORS ON CARDIOVASCULAR-
RELATED EVENT COSTS IN PATIENTS INITIATING CLOPIDOGREL
Aubert RE, Stanek EJ, Yao J, Frueh FW, Teagarden JR, Epstein RS
Medco Health Solutions, Inc, Franklin Lakes, NJ, USA
OBJECTIVES: Proton pump inhibitors (PPI) have been associated with inhibiting the 
impact of clopidogrel on cardiovascular risk. This study explores the costs associated
with cardiovascular events among patients taking clopidogrel and PPIs compared
to patients on clopidogrel alone. METHODS: We retrospectively analyzed 16,690 
patients who had undergone percutaneous coronary intervention (PCI) with stenting 
between October 2005 to September 2006, and who received clopidogrel alone (N 
9862) or with a PPI (N  6828). The primary endpoint was the incidence of major 
cardiovascular event deﬁ ned as hospitalization for myocardial infarction/unstable
angina (MI/ACS), stroke/transient ischemic attack (TIA), percutaneous coronary inter-
vention/coronary artery bypass graft (PCI/CABG), or cardiovascular death over a 12-
month period. For each primary end-point, event costs per patient-year of follow-up 
(US$2009) were calculated using Healthcare Cost and Utilization Project (HCUP) data
for 2006 hospitalization events inﬂ ated by 5%/year. Costs were derived from HCUP 
charges applying an actual cost: charge ratio of 0.4 for hospitalization. RESULTS:
The rate of primary end-point was 25.1% in patients on combined clopidogrel and 
PPI therapy and 17.9% in patients not receiving a PPI (hazard ratio 1.51, 95% conﬁ -
dence interval 1.39–1.64, p  0.001). Hospitalization event costs per pt-year related
to the composite primary end point were $6061 in patients on combined clopidogrel-
PPI therapy and $4400 in patients taking clopidogrel alone (diff  $1662 per pt-yr;
37.8%). Costs differences between combined clopidogrel-PPI therapy and clopidogrel 
alone were driven by MI/ACS ($3903 vs. $2367; 65%) and PCI/CABG ($4283 vs. 
$3508; 22%). CONCLUSIONS: Combined clopidogrel and PPI therapy signiﬁ cantly 
increased the risk of major cardiovascular events and associated costs over 12-months 
following PCI/stent placement.
CV4
ASPIRIN VERSUS CLOPIDOGREL IN COMBINATION WITH PROTON-
PUMP INHIBITORS FOR PREVENTION OF RECURRENT PEPTIC ULCER
COMPLICATIONS IN PATIENTS WITH PREVIOUS GASTROINTESTINAL
BLEEDING
Hsiao FY1, Tsai YW2, Huang WF3, Wen YW4, Chen PF4, Chang PY3, Kuo KN4
1University of Maryland School of Pharmacy, Baltimore, MD, USA, 2National Health Research 
Institutes, Zhunan Town, Taiwan, 3National Yang-Ming University, Taipei, Taiwan, 4National
Health Research Institutes, Miaoli County, Taiwan
OBJECTIVES: To compare the risk of recurrent peptic ulcer in patients who have 
experienced gastrointestinal bleeding and who require ongoing anti-platelet therapy 
(aspirin or clopidogrel) whether using proton-pump inhibitor (PPI) in combination. 
METHODS: In this population-based, retrospective cohort study, we used Taiwan’s 
2000–2006 National Health Insurance Database to explore the risk of hospitalization 


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CV3 THE IMPACT OF PROTON PUMP INHIBITORS ON CARDIOVASCULARRELATED EVENT COSTS IN PATIENTS INITIATING CLOPIDOGREL

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