Impact of Two Medicaid Prior
Authorization Policies on
Antihypertensive Use and Costs
Michael Law
Centre for Health Services and Policy Research
The University of British Columbia
Acknowledgments
• Co-authors
– Christine Lu, Stephen Soumerai, Amy Johnson
Graves, Robert LeCates, Fang Zhang, Dennis RossDegnan, Alyce Adams
• Funding
– Pharmaceutical Policy Fellowship, Harvard
University & Harvard Pilgrim Health Care Institute
– NIMH (5R01MH069776-03)
– Social Sciences and Humanities Research Council of
C
Canada
d
Background
• Hypertension
– Highly
g yp
prevalent,, p
poorlyy controlled
– About 18% of Medicaid prescriptions
• Prior authorization policies
– At least 32 States
– Controversial
– Unknown impact
Policies Studied
• Michigan
– Implemented
p
PA in March 2002
– Particularly restrictive
• Indiana
– Implemented PA in September 2002
– Combined with step
step-therapy
therapy for ARBs
Population
• All individuals
i di id l 18
18+ that
h were:
– Dually-enrolled from July 2000 through
September 2003
– Not enrolled in managed care
• Studied all antihypertensive medicines:
– Diuretics, ACE-Is, CCBs, BBs, Alpha Blockers,
ARBs
Analysis
• Outcomes
– Prescriptions
p
/ 1,000
,
enrollees
– Use of preferred and non-preferred drugs
– Reimbursement / 1
1,000
000 enrollees
• Statistical methods
– Interrupted time series analysis
Cohort Characteristics
N
Sex
Age
Female
18-44
45 64
45-64
65 and Older
Race
White
Black
Hispanic
Other
Pre-policy Drug Use Antihypertensive
Michigan Indiana
38,684 29,463
53.4%
56.3%
36.0%
34.7%
43 7%
43.7%
45 2%
45.2%
20.2%
20.1%
77.4%
84.9%
20.1%
13.6%
0.9%
0.6%
1.6%
0.9%
32.3%
31.8%
2000
2000, 7
2000, 8
2000, 9
2000, 10
2000, 11
2000, 12
2001, 1
2001, 2
2001, 3
2001, 4
2001, 5
2001, 6
2001, 7
2001, 8
2001, 9
2001, 10
2001, 11
2001, 12
2002, 1
2002, 2
2002, 3
2002, 4
2002, 5
2002, 6
2002, 7
2002, 8
2002, 9
2002, 10
2002, 11
2002, 12
2003, 1
2003, 2
2003, 3
2003, 4
2003, 5
2003, 6
2003, 7
2003, 8
2003, 9
100
Michigan Policy
M
Number of Prrescriptions perr 1,000 Enrollees
Michigan: Prescriptions
700
600
500
400
300
200
0
2001
2002
2003
2000
2000, 7
2000, 8
2000, 9
2000, 10
2000, 11
2000, 12
2001, 1
2001, 2
2001, 3
2001, 4
2001, 5
2001, 6
2001, 7
2001, 8
2001, 9
2001, 10
2001, 11
2001, 12
2002, 1
2002, 2
2002, 3
2002, 4
2002, 5
2002, 6
2002, 7
2002, 8
2002, 9
2002, 10
2002, 11
2002, 12
2003, 1
2003, 2
2003, 3
2003, 4
2003, 5
2003, 6
2003, 7
2003, 8
2003, 9
100
In
ndiana Policy
Number of Pre
escriptions per 1
1,000 Enrollees
Indiana: Prescriptions
700
600
500
400
300
200
0
2001
2002
2003
2000
2001, 5
2001, 4
2001, 3
2001, 2
2001, 1
2000, 12
2000, 11
2000, 10
2000, 9
2000, 8
2000, 7
2001
2002, 5
2002, 4
2002, 3
2002
2003, 5
2003, 4
2003, 3
2003, 2
2003, 1
2002, 12
2002, 11
2002, 10
2002, 9
2002, 8
2002, 7
2002, 6
2003
200
Preferred
150
Non-Preferred
2003, 9
2003, 8
2003, 7
2003, 6
350
Michigan Poliicy
M
400
2002, 2
2002, 1
2001, 12
2001, 11
2001, 10
2001, 9
2001, 8
2001, 7
2001, 6
Antihy
ypertensive Prescription
ns / 1,000 Enrollees
Michigan: Preferred Drugs
450
300
250
100
50
0
2000
2001, 5
2001, 4
2001
2002, 5
2002, 4
2002, 3
2002, 2
2002, 1
2001, 12
2001, 11
2001, 10
2001, 9
2001, 8
2001, 7
2001, 6
2002
2003, 5
2003, 4
2003, 3
2003, 2
2003, 1
2002, 12
2002, 11
2002, 10
2002, 9
2003
2003, 9
2003, 8
2003, 7
2003, 6
In
ndiana Policy
y
Non-Preferred
2002, 8
2002, 7
2002, 6
50
2001, 3
2001, 2
2001, 1
2000, 12
2000, 11
2000, 10
2000, 9
2000, 8
2000, 7
Antihy
ypertensive Prescription
ns / 1,000 Enrollees
Indiana: Preferred Drugs
300
250
200
150
100
Preferred
0
2000
2001, 4
2001, 3
2001, 2
2001, 1
2000, 12
2000, 11
2000, 10
2000, 9
2000, 8
2000, 7
2001
2002, 5
2002, 4
2002, 3
2002
2003, 5
2003, 4
2003, 3
2003, 2
2003, 1
2002, 12
2002, 11
2002, 10
2002, 9
2002, 8
2002, 7
2002, 6
2003
2003, 9
2003, 8
2003, 7
2003, 6
$0
In
ndiana Policy
Michigan Polic
M
cy
$2,000
2002, 2
2002, 1
2001, 12
2001, 11
2001, 10
Indiana
2001, 9
$
$4,000
2001, 8
Michigan
2001, 7
$6,000
2001, 6
2001, 5
Antihy
ypertensive Prescription
ns / 1,000 Enrollees
Pharmacy Cost
$20,000
$18,000
$16,000
$14,000
$12,000
$10,000
$8 000
$8,000
Strengths and Limitations
• Major
M j strength
h off our study
d
– Controlled, longitudinal design
• Possible limitations
–
–
–
–
No clinical outcomes
Short follow-up
follow up period
Only dual-eligibles
D ’t accountt ffor all
Don’t
ll costs
t and
d rebates
b t
Implications
• PA for antihypertensives
– Did not have a large
g impact
p
on drug
g use
– Led to large-scale switching
– Reduced Medicaid Pharmacy costs
• Important to weigh cost savings against
potential clinical impacts
For more information…
information
Michael Law
mlaw@chspr.ubc.ca
Law MR, Lu CY, Soumerai SB, Graves AJ, LeCates RF, Zhang F,
g
D, Adams AS. Impact
p
of Two Medicaid PriorRoss-Degnan
Authorization Policies on Antihypertensive Use and Costs Among
Michigan and Indiana Residents Dually Enrolled in Medicaid and
Medicare: Results of a Longitudinal
Longitudinal, Population
Population-Based
Based Study.
Study
Clinical Therapeutics 2010; 32(4):729-741.