Gaps in Drug Benefits: Impact on
Utilization and Spending for Drugs Used
by Medicare Beneficiaries with Serious
Mental Illness
Linda Simoni-Wastila, PhD
(lsimoniw@rx.umaryland.edu)
Christopher Blanchette, MA
Xiaoqang Ren, MS
Bruce Stuart, PhD
Peter Lamy Center on Drug Therapy and Aging
University of Maryland Baltimore
School of Pharmacy
AcademyHealth
Boston, MA
June 28, 2005
Funded by the Robert Wood Johnson Foundation/Health Care and Financing Organization
Background
There are growing concerns that the MMA
Part D benefit’s “donut hole” design may
result in discontinuities in access to
prescribed medicines
Such coverage gaps may be particularly
detrimental to older and disabled
individuals with chronic conditions for
whom prescription drugs represent a
necessary treatment modality
Background
Prior work found that drug coverage gaps
reduced prescription drug use by Medicare
beneficiaries. Using a simulation model, we
projected total drug spending under Medicare
Part D relative to those with continuous
coverage:
– All MC Beneficiaries: 92.1%
– COPD: 79.6%
– Diabetes: 83.2%
– Mental Illness: 76.0%
(Stuart, Simoni-Wastila and Chauncey Health Affairs web exclusive 2005)
Purpose
To delve into greater detail on how drug
coverage gaps impact drug use and
spending by Medicare beneficiaries with
serious mental illness (SMI)
Objectives:
– 1) To describe extent of drug coverage gaps
experienced by SMI Medicare beneficiaries; and
– 2) To determine impact of coverage gaps on use of
and spending for prescription drugs used to treat
mental disorders
Methods - Data
1997 – 2001 Medicare Current Beneficiary Survey
(MCBS) linked to Medicare Part A and Part B claims
MCBS is longitudinal, nationally-representative sample
of Medicare beneficiaries
MCBS (linked to Part A and B claims) contains:
– Demographics
– Income and health insurance coverage, including drug benefits
(with begin and end dates of coverage)
– Health and functional status
– Utilization and expenditures for all health services, including
prescription drugs
– Diagnostic information (ICD-9 diagnoses from claims; self-report
from MCBS survey)
Methods – Study Sample
Pooled sample of three 3-year cohorts
(1997-1999, 1998-2000, and 1999-2001)
of community-dwelling MCBS respondents
Excluded from analysis: M + C plan
members, LTC residents, and those lost to
follow-up  Sample = 9,219
Methods – Study Sample
SMI defined as: 1 or more SMI diagnoses in baseline
year + at least one other of same diagnosis during any of
study years
SMI diagnoses include:
– Schizophrenia/psychotic disorders (ICD-9 = 294.xx, 295.xx,
297.xx, 298.xx, and 299.xx)
– Manic/Bipolar disorders (ICD-9 = 296.0, 296.1, 296.4-296.9)
– Major depression (ICD- 9 = 296.2, 296.3)
Application of these criteria resulted in an analytic
sample of 901 seriously mentally-ill Medicare
beneficiaries followed for up to 3 years
Methods – Dependent Variables
Mental health drug use and spending
Use defined as all Prescription Medication Events (PME) per
respondent over three year period
– % use, annual mean PMEs
Expenditures defined as all mental health drug spending per
respondent over three period, expressed in constant 2001
dollars (and annualized)
Total mental health drug use and spending, as well as by
therapeutic class:
–
–
–
–
–
Antipsychotics (atypicals, typicals)
Antidepressants (newer, traditional)
Anxiolytics/Sedative-hypnotics
Anti-mania drugs
Anticonvulsants (“mood-stabilizers”)
Methods – Independent Variables
Prescription gap months = summed
number of months over the three-year
period during which the beneficiary had no
evidence of prescription drug coverage
– 0 Gap Months (Full drug coverage) [ref]
– 1-18 Gap Months
– 19-35 Gap Months
– 36 Gap Months (No drug coverage)
Methods - Covariates
Age (<65, 65-74, 75-84, 85+ [ref])
Gender [Female is ref]
Race/ethnicity [Non-white is ref]
Education [<HS is ref]
Income [FPL > 300 is ref]
Non-drug supplemental insurance (0/1)
Geographic region [West is ref]
Urbanicity [Rural is ref]
Health Status [Poor is ref]
Death status (0/1 indicator of died in year 1, 2 or 3)
Psychosis or depression (0/1 indicator of condition)
Comorbidity Index (DCG/HCC)
Methods – Analytic Approach
Descriptive: Mental health drug use and
spending, overall and by gap status
Multivariate: Ordinary least squares regression
to estimate the impact of gap status on mental
health drug use and spending
– Tested for endogeneity of the coverage variables and
found that controlling for comorbidity (HCC/DCG)
eliminated all endogeneity
All analyses weighted  nationally
representative estimates
Results – Baseline Characteristics
Percent of SMI Beneficiaries
Age < 65
34.1%
Female
61.7
White
82.0
≤ 100% FPL
31.0
Fair/Poor Health
Mental Health Problems
Major Depression
Psychotic Disorders/Bipolar
Non-SMI MH conditions
Died
Year 1
Year 2
Year 3
44.8
52.8
55.0
67.3
4.3
5.2
6.2
Annual Mean Total and MH Drug
Spending by MC Beneficiaries (unadjusted)
$2,500
$2,421
$2,000
34.0%
$1,550
$1,500
10.7%
$1,000
$824
$500
$166
$0
SMI MC Beneficiaries
Annual Mean Total Drug Spending
All MC Beneficiaries
Annual Mean MMH Spending
Drug Coverage Gaps Among MC
Beneficiaries with SMI (unadjusted)
Prescription
Coverage Gaps
in Months
% of MC
Beneficiaries
with SMI
Mean Annual
PME Fills by SMI
MC Beneficiaries
0 (Full drug
coverage)
1-18 Months
51.4%
11.2
18.7%
9.6
19-35 Months
11.5%
6.3
36 Months (No
coverage)
18.4%
6.0
Proportion of SMI MC Beneficiaries Using Any
MH Drugs, Antidepressants and Antipsychotics
by Coverage Gap Status (unadjusted)
90.0
80.0
83.2
79.1
77.0
70.0
60.0
66.5
66.0
61.5
61.1
56.7
50.8
50.0
43.1
40.0
32.6
30.0
27.9
27.2
19.3
20.0
15.2
10.0
0.0
All SMI
Full
Coverage
All MH Drugs
1-18 Gap
Months
Antidepressants
19-35 Gap
Months
No
Coverage
Antipsychotics
Regression Results
The next several slides illustrate the
impact of having coverage gaps on
utilization of and spending on
All mental health drugs
Antidepressants
Antipsychotics
ceteris paribus
All findings are presented as mean annual
prescriptions or expenditures
Annual Mean PMEs (Fills) by Coverage Gap
Status (adjusted)
12.0
10.0
10.1
7.9
8.0
6.9
7.0
6.0
4.0
3.6
2.5
Full Coverage 1-18 Gap Months
All MH Drugs
2.5
2.2
1.8
2.0
0.0
2.3
1.7
1.4
19-35 Gap
Months
Antidepressants
No Coverage
Antipsychotics
Annual Mean Drug Spending by Coverage Gap
Status (adjusted)
$900
$893
$800
$742
$700
$612
$600
$572
$500
$400
$300
$297
$330
$308
$174
$200
$238
$210
$175
$151
$100
$0
Full Coverage 1-18 Gap Months
All Mental Health
19-35 Gap
Months
Antidepressant
No Coverage
Antipsychotics
Other Multivariate Findings
Age is important – individuals aged <65 (i.e., the
disabled) had significantly increased use and
spending of all MH drugs and drug classes
relative to those aged 85+
Sex, race/ethnicity, income, health status, and
other covariates varied by therapeutic class
Comorbidity, as assessed using the DCG/HCC,
was not a significant predictor of MH drug use or
spending; however, the individual diagnoses of
depression and psychotic disorders were
significant positive predictors of drug use and
spending
Other Multivariate Findings
In within therapeutic class analyses (not shown
here), we found that coverage gaps did not
influence use of and spending on the newer
mental health drugs, such as the atypical
antipsychotics or SSRI/SNRIs, suggesting that
coverage status may not influence type of drug
one receives
– However, when we examined the probability of
receiving any “newer” MH drug (ie, any SSRI/SRNI or
atypical), we found that among any antidepressant/
antipsychotic users, “newer” drug use and spending
was less likely among those with gaps or no coverage
relative to those with full coverage
Conclusions and Next Steps
It is clear that coverage gaps make a difference in terms
of access to medications used to treat Medicare
beneficiaries with serious mental illness, controlling for
comorbidity and other important covariates
Next Steps
– Examine variation in use of and spending for other MH
therapeutic categories (e.g., mood stabilizers; anxiolytics;
“newer” MH drugs)
– Examine how use and spending differ by age (i.e., eligibility
based on disability versus age)
– Answer the question: Do differences in mental health drug use
due to coverage gaps impact the use of and spending on other
medical services, including hospitalization, emergency
department visits, and psychiatric treatment?