Effect of Increased Copayments on Pharmacy Use in the Department of Veterans Affairs

1
Effect of Increased Copayments on Pharmacy Use in
the Department of Veterans Affairs

• Kevin T. Stroupe, PhD1,2,3,4
• 1 Midwest Center for Health Services Policy
  Research, Hines VA Hospital, Hines, IL
• 2 Cooperative Studies Program Coordinating
  Center, Hines VA Hospital, Hines, IL
• 3 VA Information Resource Center, Hines VA
  Hospital, Hines, IL
• 4 Northwestern University Feinberg School of
  Medicine, Chicago, IL

2
Collaborators

• Bridget M. Smith, PhD1
• Todd A. Lee, PharmD, PhD1,3
• Ramon Durazo-Arvizu, PhD1
• Elizabeth Tarlov, PhD1,4
• Lishan Cao, MS3
• Zhiping Huo, MS3
• Tammy Barnett, MA1,2
• Denise Hynes, PhD, RN1,4
• Kevin Weiss, MD1,3
• 1 Midwest Center for Health Services Policy
  Research, Hines, IL
• 2 Cooperative Studies Program Coordinating
  Center, Hines, IL
• 3 Northwestern University Feinberg School of
  Medicine, Chicago, IL
• 4 VA Information Resource Center, Hines, IL

3
Background

• In 2001, VA spent over 3 billion on outpatient
  medications
• As in the private sector, the VA has increased
  cost sharing by patients

4
Background

• February 4, 2002 VA raised the medication
  copayment from 2 to 7 per 30-day supply
• This increase was the first change in the
  copayment amount for medications since the
  copayment was instituted in 1990

5
Study Objectives

• To examine the association of the copayment
  increase with medication acquisition from VA
  pharmacies
• For all chronic medications
• For specific categories of medications
• To examine the association of the copayment
  increase with medication acquisition for higher
  and lower pharmacy users

6
Study Objectives

• To examine rates of discontinuation of VA
  pharmacy use
• For all chronic medications, over-the-counter
  (OTC) medications, and prescription only
  medications
• For medications to treat common chronic conditions

7
SettingMedication Copayments in VA

• Veterans may obtain both Rx-only medications and
  OTC medications from VA pharmacies
• All medications require a prescription from VA
• The same copayment applies to Rx-only and OTC
  medications
• Veterans are not subject to copayments for
  supplies (e.g., gauze) from the VA pharmacy

8
SettingMedication Copayments in VA

• Veterans are subject to the copayment depending
  on their VA Priority category (1 though
  8),
• which were established to manage access to VA
  care in relation to VAs resources

9
SettingMedication Copayments in VA

• Veterans in Priority 1
• have a service-connected condition that is 50 or
  more disabling
• are exempt from drug copayments

10
SettingMedication Copayments in VA

• Veterans in Priorities 2 through 6
• have service-connected conditions lt50 disabling,
  low incomes, or other recognized statuses (e.g.,
  former POW)
• are exempt from copayments for drugs for their
  service-connected disabilities
• have a cap on their out-of-pocket medication
  spending set at 840 annually (increased to 960
  in 2006)

11
SettingMedication Copayments in VA

• Veterans in Priorities 7 and 8
• are subject to copayments for all drugs
• have no cap on their annual out-of-pocket
  prescription copayments

12
SettingMedication Copayments in VA

• Veterans may have copayments for
• No Drugs
• Priority Category 1
• Some Drugs
• Priority Categories 2 - 6
• All Drugs
• Priority Categories 7 - 8

13
Study Design

• Retrospective observational study using data from
  national VA databases
• We examined medication acquisition of patients
  from VA in the 1-year periods
• before (February 4, 2001 to February 3, 2002) and
  
• after (February 4, 2002 to February 4, 2003) the
  copayment increase

14
Study Sample

• 5 random sample of male VA users in fiscal year
  (FY) 2001
• To ensure that differences in medication
  acquisition before and after the copayment
  increase were not due to length of time in the
  study, we restricted sample to
• veterans who used VA inpatient or outpatient
  services in the 1-year period before the study
• veterans who were alive at the end of the study
  period

15
Study Timeline
16
Study Sample
17
Data Sources for Study

• VA Pharmacy Benefit Management (PBM) Database
• Used to obtain Medication acquisition 1 year
  before and after copayment increase (Feb 4, 2001
  Feb 4, 2003)
• VA National Patient Care Database (NPCD) Medical
  SAS Datasets
• Used to obtain Patient characteristics
• e.g., age, race, etc.
• VA Enrollment file
• Used to obtain Veteran priority category

18
Pharmacy Utilization

• VA copayment applies to each 30-day supply or
  less
• We calculated the number of 30-day equivalent
  supplies by dividing the days supply as
  dispensed by 30
• e.g., one prescription with an 90-day supply
  dispensed became three 30-day equivalent supplies
• We considered a prescription with lt30-day supply
  as one 30-day supply because the full copayment
  applies to these prescriptions

19
Pharmacy Utilization

• Patients may obtain drugs from VA to treat
  chronic conditions (e.g., hypertension) or for
  short-term conditions (e.g., infections)
• Because changes in acquisition of drugs for
  chronic conditions could affect the long-term
  management and consequences of these conditions,
• we focused on drugs for chronic rather than acute
  conditions

20
Pharmacy Utilization

• To exclude medications that were likely to be
  used on a short-term basis
• we removed any type of drug that the patient did
  not receive at least one 30-day supply before or
  after the copayment increase

21
Pharmacy Use Categories

• We divided patients into higher and lower
  pharmacy use groups based on the number of
  different medications patients received before
  the copayment increase

22
Pharmacy Use Categories

• Based on quartiles of the number different
  medications, we grouped patients as
• low medication users ( 3 medications)
• moderately low users (4 6 medications),
• moderately high users (7 11 medications)
• and high users (gt 11 medications)

23
Medication Categories

• All chronic medications
• Medications with al least one 30-day supply

24
Medication Categories

• Higher and lower-cost medications
• medications with a retail cost more or less than
  the copayment
• Based on adjusted Average Wholesale Price
• OTC and Rx-only medications
• Based on indicator variables in the database

25
Medication Categories

• More and less essential medications
• Medications that prevented deterioration in
  health, prolonged life, and were not likely to be
  prescribed without a definitive diagnosis
• Medications were that could relieve symptoms
  without affecting the underlying disease process
• Based on modified lists from WHO that have been
  used in previous studies

26
Medication Categories

• Medications for chronic conditions
• These medications included anti-hypertensives,
  lipid lowering agents, anti-coagulants, diabetes
  medications, antiarrhythmics, antianginals,
  antidepressants, and antipsychotics
• To ensure that antidepressant users were not
  receiving them on only a short-term basis, we
  restricted antidepressant users to
• Patients with Dx of depression during the 2 years
  prior to the copayment increase
• Who were using an antidepressant at the beginning
  of the study period

27
Analysis

• To examine the effect of the copayment on the
  number of 30-day supplies in the 1-year periods
  before and after the copayment increase
• We used zero-inflated negative binomial count
  models
• controlling for age, race, comorbidities,
  insurance status, distance, and socio-economic
  status

28
Analysis

• To determine the impact of the copayment increase
  on medication acquisition from the VA,
• we used the natural experiment that occurred when
  the copayment was increased for certain veterans
• Veterans with no copays were control group
• Veterans with copays for some or all medications
  were experimental groups

29
Analysis

• We used a difference-in-differences approach to
• estimate the change in number of 30-day supplies
  after the increase for veterans subject to the
  copayment relative to
• the change in number of 30-day supplies after the
  increase for veterans with no copayments

30
Analysis

• Advantage of difference-in-differences method
• any change in control groups medication
  acquisition reflects changes unrelated to the
  copayment
• while any change in the experimental groups
  medication acquisitions reflects both the (same)
  naturally occurring change plus the impact of the
  copayment change

31
Analysis

• To implement the difference-in-differences
  estimator, we specified the conditional mean
  number of 30-day prescriptions from VA as
• E(yitxit) (1-qit) exp(ß0 ß1Some_copayit
  ß2All_copayit ß3Postt ß4Some_copayit ?
  Postt ß5 All_copayit ? Postt ?'zit)
• Where Some_copayit is an indicator that patient
  i was subject to
• the copayment for some medications in period
  t,
• All_copayit is an indicator that the patient was
  subject to the
• copayment for all medications,
• Postt is an indicator whether the copayment
  increase was
• applicable in period t,
• Some_copayit ? Postt and All_copayit ? Postt
  indicate
• patients subject to the copayment after the
• copayment increase
• zit are other patient characteristics

32
Analysis

• To examine the impact of copay increase on
  discontinuation of VA pharmacy services (for all
  chronic medications, Rx-only medications, OTC
  medications, and medications for specific
  conditions),
• we used multivariable logistic regression models
  to examine the probability of discontinuing VA
  pharmacy use for medications after the copayment
  increase
• For all models, the veterans with no medication
  copayments were the reference group

33
Analysis

• For each logistic regression model, we included
  only patients who had a prescription for the type
  of medication being examined

34
Patient Characteristics by Copay Category
35
Monthly 30-Day SuppliesAll Chronic Drugs
Copay Increase
36
Adjusted Change in Number of 30-Day Supplies
Annually After Copay IncreaseAll Chronic Drugs
37
Adjusted Change in Number of 30-Day Supplies
Annually After Copay Increase
38
Percentage Reduction in Annual Number of 30-Day
Supplies Following Copay Increase
39
Number of 30-Day SuppliesLow Medication Users
40
Number of 30-Day SuppliesModerately Low
Medication Users
41
Number of 30-Day SuppliesModerately High
Medication Users
42
Number of 30-Day SuppliesHigh Medication Users
43
Change in Number of 30-Day Supplies After Copay
By Medication User Groups
NS
NS Not Significant for all other values P lt
0.01
NS
Copays for No Drugs
Copays for All Drugs
Copays for Some Drugs
44
Percent of Patients Discontinuing VA Pharmacy
After Copay Increase


P lt 0.001




45
Percent of Patients Discontinuing VA Pharmacy
After Copay Increase








P lt 0.001



46
Discontinuation of VA Pharmacy UseOdds Ratios
from Logistic Regression Analyses
P lt 0.001
47
Discontinuation of VA Pharmacy UseOdds Ratios
from Logistic Regression Analyses
P lt 0.001
48
Discontinuation of VA Pharmacy UseOdds Ratios
from Logistic Regression Analyses
P lt 0.001
49
Conclusions

• For veterans subject to the copayment, the number
  of 30-day supplies from VA fell following the
  copayment increase
• The copayment increase had a larger effect as the
  number of different drugs that patients received
  increased
• E.g., for high medication users with copays for
  all drugs
• Copays increased gt 300 annually
• (218 to 670)
• Drug acquisition decreased 12

50
Conclusions

• Longer-term follow-up is needed to determine if
  the decrease in drug acquisition of moderately
  high or high medication users had adverse health
  effects

51
Conclusions

• The copay increase had a relatively larger effect
  on acquisition of lower cost and OTC medications
• Charging veterans copayments for some drugs that
  is larger than they might pay elsewhere might
  lead veterans to obtain drugs from multiple
  pharmacies, limiting VAs ability to monitor for
  drug-drug interactions or discontinuation

52
Conclusions

• The copayment increase had a significant effect
  on the probability of discontinuing VA pharmacy
  use for all chronic medications, Rx-only and OTC
  medications, and for medications to treat chronic
  conditions including hypertension and depression
• If these medications are not obtained elsewhere
  there could be unintended consequences on health
  outcomes and overall health care costs