Abstract P206: Differences in the Characteristics of Medicare Beneficiaries with Heart Failure According to Enrollment in the Medicare Part D Prescription Drug Benefit
Authors: Eapen Zubin J , Hammill Bradley G , Setogouchi Soko , Schulman Kevin A , Peterson Eric D , Hernandez Adrian F , Curtis Lesley H 
Published: July 2021

Background
The need for comparative effectiveness studies is a national priority because efficacy studies for drug approval enroll highly selected patients. In particular, comparative effectiveness of drug therapies in heart failure (HF) is needed because HF represents a substantial portion of annual Medicare spending. Drug exposures are now captured for Medicare beneficiaries enrolled in prescription drug plans (Part D), but the population of Part D enrollees with HF has not been described.

Methods
Using a 5% national sample of Medicare claims data, we created 2 annual cohorts of Medicare beneficiaries having prevalent HF as of January 1, 2006 and January 1, 2007. We included beneficiaries aged 65 years or older who had at least 12 months of prior fee-for-service enrollment and had HF reported on one inpatient claim or at least 3 outpatient claims during the prior year. We classified patients according to enrollment in a Part D plan as of January 1st of the cohort year. We compared demographics and comorbidities of patients enrolled to those not enrolled in a Part D plan.

Results
We identified 91,135 eligible beneficiaries with prevalent HF as of January 1, 2006 and 87,344 as of January 1, 2007. Among the 2006 cohort, 35,883 (39%) had enrolled in a Part D plan as of January 1, 2006. Enrollment increased to 50,834 (58%) in the 2007 cohort. Part D enrollees tended to have fewer comorbidities and were more likely to be female and black (Table). Additionally, Part D enrollees were more likely to have a portion of their Medicare Part A and B premiums paid for by the state (state buy-in), an indication of low-income status.

Conclusions
Medicare beneficiaries with HF differ significantly according to enrollment in Part D prescription drug plans and represent a population underrepresented in clinical efficacy trials. Studies with Part D claims data linked to a clinical registry may inform clinical practice as to the effectiveness of drug therapy in real-world settings.

Baseline characteristics of Medicare beneficiaries with HF according to enrollment in Part D
*

Variable
2006
2007

Not Part D Enrolled
Part D Enrolled
Not Part D Enrolled
Part D Enrolled

N
55,252
35,883
36,510
50,834

Demographics

Age, mean (SD),y
80.1 (7.6)
80.7 (8.2)
80.1 (7.4)
80.7 (8.1)

Gender, male
26,447 (47.9%)
11,083 (30.9%)
19,087 (52.3%)
17,242 (33.9%)

Race, non-white
6,434 (11.7%)
7,622 (21.2%)
4,011 (11.0%)
9,465 (18.6%)

State buy-in
1,713 (3.1%)
19,419 (54.1%)
208 (0.6%)
19,808 (39.0%)

Comorbidities

Coronary heart disease
40,606 (73.5%)
25,026 (69.7%)
27,172 (74.4%)
35,960 (70.7%)

Diabetes mellitus
24,093 (43.6%)
18,197 (50.7%)
16,381 (44.9%)
25,156 (49.5%)

Cerebrovascular disease
17,350 (31.4%)
12,714 (35.4%)
11,745 (32.2%)
17,734 (34.9%)

Myocardial infarction
12,988 (23.5%)
7,436 (20.7%)
8,565 (23.5%)
10,787 (21.2%)

Peripheral vascular disease
20,079 (36.3%)
14,779 (41.2%)
13,708 (37.5%)
20,861 (41.0%)

*

p values for all comparisons are <.001