Why carry out this study?
|
Reduced adherence and persistence of direct oral anticoagulants (DOACs) use are associated with increased risk of poor clinical outcomes including increased risk of stroke and systemic embolism (SE) among Medicare beneficiaries |
Increased out-of-pocket (OOP) costs that Medicare beneficiaries experience during the Medicare coverage gap phase may lead to reduced adherence and persistence of DOACs |
We examined the implications of increases in OOP costs during the Medicare coverage gap on patterns of DOAC use and incidence of stroke and SE among beneficiaries with non-valvular atrial fibrillation |
What was learned from this study?
|
Medicare beneficiaries not receiving financial assistance via the low-income subsidy (LIS) had a significantly higher risk of discontinuing DOACs compared to those receiving subsidies to shield them from increased OOP costs, which subsequently increased the risk of serious cardiovascular events (stroke and SE) |
Reducing shifts in cost sharing burden could minimize medication discontinuation and improve overall health of vulnerable populations |
Introduction
Methods
Data Source
Study Design
Study Populations
Measures
Baseline Characteristics
Follow-Up Outcomes
Statistical Analysis
Results
Baseline Characteristics
All beneficiaries | LIS [A] | Non-LIS [A] | Standardized differencea [A] vs. [B] | |
---|---|---|---|---|
N = 303,695 | N = 84,857 | N = 218,838 | ||
Demographic characteristics at index dateb | ||||
Age, years | ||||
Mean ± SD | 77.3 ± 7.8 | 77.9 ± 8.4 | 77.1 ± 7.6 | 10.03%† |
Male, n (%) | 133,673 (44.0%) | 29,667 (35.0%) | 104,006 (47.5%) | − 25.74%† |
Region of residence, n (%) | 21.67%† | |||
Northeast | 57,860 (19.1%) | 19,486 (23.0%) | 38,374 (17.5%) | |
Midwest | 71,611 (23.6%) | 15,518 (18.3%) | 56,093 (25.6%) | |
South | 122,400 (40.3%) | 34,274 (40.4%) | 88,126 (40.3%) | |
West | 51,382 (16.9%) | 15,537 (18.3%) | 35,845 (16.4%) | |
Other/unknownc | 442 (0.1%) | 42 (0.0%) | 400 (0.2%) | |
Race, n (%) | 67.89%† | |||
White | 262,166 (86.3%) | 59,055 (69.6%) | 203,111 (92.8%) | |
Black | 12,848 (4.2%) | 8761 (10.3%) | 4087 (1.9%) | |
Asian | 7083 (2.3%) | 4817 (5.7%) | 2266 (1.0%) | |
Hispanic | 14,302 (4.7%) | 10,143 (12.0%) | 4159 (1.9%) | |
North American native, other, or unknown | 7296 (2.4%) | 2081 (2.4%) | 5215 (2.3%) | |
Year of index date, n (%) | 7.80% | |||
2015 | 16,698 (5.5%) | 4122 (4.9%) | 12,576 (5.7%) | |
2016 | 46,798 (15.4%) | 14,078 (16.6%) | 32,720 (15.0%) | |
2017 | 55,918 (18.4%) | 15,845 (18.7%) | 40,073 (18.3%) | |
2018 | 82,303 (27.1%) | 22,792 (26.9%) | 59,511 (27.2%) | |
2019 | 101,978 (33.6%) | 28,020 (33.0%) | 73,958 (33.8%) | |
Clinical characteristics during baseline periodd | ||||
CHA2DS2-VASc scoree,f | ||||
Mean ± SD | 4.0 ± 1.5 | 4.5 ± 1.6 | 3.8 ± 1.4 | 48.43%† |
n (%) | 45.55%† | |||
0–1 | 8127 (3.0%) | 1275 (1.7%) | 6852 (3.4%) | |
2 | 36,803 (13.4%) | 5726 (7.7%) | 31,077 (15.6%) | |
3 | 65,894 (24.0%) | 13,229 (17.8%) | 52,665 (26.4%) | |
4 | 73,176 (26.7%) | 18,745 (25.2%) | 54,431 (27.3%) | |
5 | 48,286 (17.6%) | 16,906 (22.7%) | 31,380 (15.7%) | |
6 | 25,866 (9.4%) | 10,788 (14.5%) | 15,078 (7.6%) | |
≥ 7 | 15,838 (5.8%) | 7780 (10.5%) | 8058 (4.0%) | |
HAS-BLED scoree,g | ||||
Mean ± SD | 2.3 ± 0.9 | 2.5 ± 0.9 | 2.2 ± 0.8 | 29.79%† |
n (%) | 33.48%† | |||
0–1 | 41,488 (15.1%) | 8491 (11.4%) | 32,997 (16.5%) | |
2 | 144,103 (52.6%) | 35,019 (47.0%) | 109,084 (54.7%) | |
3 | 65,989 (24.1%) | 21,470 (28.8%) | 44,519 (22.3%) | |
≥ 4 | 22,410 (8.2%) | 9469 (12.7%) | 12,941 (6.5%) | |
Quan-CCI scored,g | ||||
Mean ± SD | 1.2 ± 1.5 | 1.8 ± 1.7 | 1.0 ± 1.3 | 56.56%† |
Other relevant comorbidities, n (%) | ||||
Cardiac arrhythmia | 248,775 (81.9%) | 65,195 (76.8%) | 183,580 (83.9%) | − 17.84%† |
Hypertension, uncomplicated | 215,817 (71.1%) | 61,085 (72.0%) | 154,732 (70.7%) | 2.83% |
Hypertension, complicated | 38,008 (12.5%) | 14,305 (16.9%) | 23,703 (10.8%) | 17.52%† |
Coronary artery disease | 90,411 (29.8%) | 27,485 (32.4%) | 62,926 (28.8%) | 7.90% |
Peripheral artery disease | 35,885 (11.8%) | 15,808 (18.6%) | 20,077 (9.2%) | 27.59%† |
Hyperlipidemia | 153,619 (50.6%) | 40,377 (47.6%) | 113,242 (51.7%) | − 8.34% |
Obesity | 49,438 (16.3%) | 13,683 (16.1%) | 35,755 (16.3%) | − 0.58% |
Smoking history | 47,094 (15.5%) | 13,433 (15.8%) | 33,661 (15.4%) | 1.24% |
Strokeh/SE | 7453 (2.5%) | 2934 (3.5%) | 4519 (2.1%) | 8.51% |
Strokeh | 7194 (2.4%) | 2817 (3.3%) | 4377 (2.0%) | 8.21% |
Medication use during baseline periodd,j | ||||
Cardiovascular-related medications, n (%) | 295,300 (97.2%) | 83,024 (97.8%) | 212,276 (97.0%) | 5.29% |
Non-oral anticoagulant therapyi | 1228 (0.4%) | 453 (0.5%) | 775 (0.4%) | 2.70% |
Antihyperlipidemic agentsj | 189,724 (62.5%) | 54,474 (64.2%) | 135,250 (61.8%) | 4.95% |
Antihypertensivesk | 260,004 (85.6%) | 74,614 (87.9%) | 185,390 (84.7%) | 9.36% |
Antiplatelet agentsl | 19,875 (6.5%) | 7092 (8.4%) | 12,783 (5.8%) | 9.81% |
Other cardiovascular medicationsm | 178,863 (58.9%) | 52,753 (62.2%) | 126,110 (57.6%) | 9.27% |
Anti-hyperglycemic agents, n (%) | 51,631 (17.0%) | 18,380 (21.7%) | 33,251 (15.2%) | 16.73%† |
All-cause healthcare costs during baseline periodd,o | ||||
Total costs (medical + pharmacy) | ||||
Mean ± SD | $8577 ± $13,788 | $11,115 ± $17,474 | $7593 ± $11,915 | 23.55%† |
Total medical costs | ||||
Mean ± SD | $6013 ± $13,512 | $7978 ± $17,151 | $5252 ± $11,714 | 18.56%† |
Total pharmacy costs | ||||
Mean ± SD | $2564 ± $2298 | $3138 ± $3235 | $2341 ± $1759 | 30.59%† |
Additional beneficiary characteristics | ||||
Months of follow-upp | ||||
Mean ± SD | 3.7 ± 1.9 | 3.5 ± 1.7 | 3.8 ± 1.9 | − 12.56%† |
Duration of DOAC treatment prior to the index dateq | ||||
Mean ± SD | 9.1 ± 7.0 | 9.2 ± 7.8 | 9.1 ± 6.7 | 2.25% |
Month of entering coverage gap, n (%) | 41.72%† | |||
January–March | 14,812 (4.9%) | 8530 (10.1%) | 6282 (2.9%) | |
April–June | 55,498 (18.3%) | 21,009 (24.8%) | 34,489 (15.8%) | |
July–September | 236,019 (45.3%) | 33,355 (39.3%) | 28,800 (47.7%) | |
October–December | 95,742 (31.6%) | 21,963 (25.9%) | 30,893 (33.7%) |
All beneficiaries | Unadjusted | IPTW-adjusteda | |||||
---|---|---|---|---|---|---|---|
Discontinue [A] | Non-discontinue [B] | Standardized differenceb [A] vs. [B] | Discontinue [A] | Non-Discontinue [B] | Standardized differenceb [A] vs. [B] | ||
N = 270,405 | N = 91,397 | N = 179,008 | N = 91,397 | N = 179,008 | |||
Demographic characteristics at index datec | |||||||
Age, years | |||||||
Mean ± SD | 77.7 ± 7.6 | 77.4 ± 7.3 | 77.8 ± 7.7 | − 6.03% | 77.3 ± 7.2 | 77.4 ± 7.5 | − 1.58% |
Male, n (%) | 128,740 (47.6%) | 43,637 (47.7%) | 85,103 (47.5%) | 0.41% | 43,461 (47.6%) | 85,701 (47.9%) | − 0.65% |
Region of residence, n (%) | 14.59%† | 12.31%† | |||||
Northeast | 47,352 (17.5%) | 14,648 (16.0%) | 32,704 (18.3%) | 13,702 (15.0%) | 29,935 (16.7%) | ||
Midwest | 68,780 (25.4%) | 20,958 (22.9%) | 47,822 (26.7%) | 19,242 (21.1%) | 43,321 (24.2%) | ||
South | 109,049 (40.3%) | 40,789 (44.6%) | 68,260 (38.1%) | 43,646 (47.8%) | 75,940 (42.4%) | ||
West | 44,803 (16.6%) | 14,855 (16.3%) | 29,948 (16.7%) | 14,607 (16.0%) | 29,398 (16.4%) | ||
Other/unknownd | 421 (0.2%) | 147 (0.2%) | 274 (0.2%) | 200 (0.2%) | 413 (0.2%) | ||
Race, n (%) | 8.24% | 0.00% | |||||
White | 252,280 (93.3%) | 84,830 (92.8%) | 167,450 (93.5%) | 84,436 (92.4%) | 166,516 (93.0%) | ||
Black | 4670 (1.7%) | 1905 (2.1%) | 2765 (1.5%) | 2131 (2.3%) | 3437 (1.9%) | ||
Asian | 2590 (1.0%) | 974 (1.1%) | 1616 (0.9%) | 1053 (1.2%) | 1806 (1.0%) | ||
Hispanic | 4723 (1.7%) | 1896 (2.1%) | 2827 (1.6%) | 2186 (2.4%) | 3468 (1.9%) | ||
North American native, other, or unknown | 6142 (2.2%) | 1792 (1.9%) | 4350 (2.4%) | 1591 (1.8%) | 3781 (2.1%) | ||
Year of index date, n (%) | 24.53%† | 16.10%† | |||||
2015 | 18,990 (7.0%) | 6252 (6.8%) | 12,738 (7.1%) | 5141 (5.6%) | 13,738 (7.7%) | ||
2016 | 38,194 (14.1%) | 14,842 (16.2%) | 23,352 (13.0%) | 14,951 (16.4%) | 28,911 (16.2%) | ||
2017 | 50,371 (18.6%) | 19,019 (20.8%) | 31,352 (17.5%) | 19,873 (21.7%) | 36,096 (20.2%) | ||
2018 | 75,572 (27.9%) | 28,346 (31.0%) | 47,226 (26.4%) | 31,001 (33.9%) | 51,926 (29.0%) | ||
2019 | 87,278 (32.3%) | 22,938 (25.1%) | 64,340 (35.9%) | 20,431 (22.4%) | 48,336 (27.0%) | ||
Clinical characteristics during baseline periode | |||||||
CHA2DS2-VASc scoref,g | |||||||
Mean ± SD | 3.7 ± 1.4 | 3.8 ± 1.4 | 3.7 ± 1.4 | 9.44% | 3.8 ± 1.4 | 3.7 ± 1.4 | 10.06%† |
n (%) | 9.72% | 12.53%† | |||||
0–1 | 8141 (3.3%) | 2320 (2.8%) | 5821 (3.5%) | 2149 (2.6%) | 5644 (3.4%) | ||
2 | 38,077 (15.4%) | 11,602 (13.9%) | 26,475 (16.1%) | 11,224 (13.4%) | 26,236 (15.8%) | ||
3 | 66,463 (26.9%) | 21,507 (25.9%) | 44,956 (27.4%) | 21,385 (25.5%) | 44,849 (27.1%) | ||
4 | 70,933 (28.7%) | 24,650 (29.6%) | 46,283 (28.2%) | 24,824 (29.6%) | 46,148 (27.9%) | ||
5 | 39,838 (16.1%) | 14,361 (17.3%) | 25,477 (15.5%) | 14,895 (17.8%) | 26,216 (15.8%) | ||
6 | 16,637 (6.7%) | 6016 (7.2%) | 10,621 (6.5%) | 6321 (7.5%) | 11,282 (6.8%) | ||
≥ 7 | 7406 (3.0%) | 2726 (3.3%) | 4680 (2.8%) | 2995 (3.6%) | 5191 (3.1%) | ||
HAS-BLED scoref | |||||||
Mean ± SD | 2.1 ± 0.8 | 2.2 ± 0.8 | 2.1 ± 0.8 | 14.62%† | 2.2 ± 0.8 | 2.1 ± 0.8 | 13.19%† |
n (%) | 12.52%† | 12.68%† | |||||
0–1 | 43,592 (17.6%) | 12,350 (14.8%) | 31,242 (19.0%) | 11,613 (13.9%) | 29,136 (17.6%) | ||
2 | 141,644 (57.2%) | 47,272 (56.8%) | 94,372 (57.4%) | 47,623 (56.8%) | 94,963 (57.4%) | ||
3 | 50,303 (20.3%) | 18,468 (22.2%) | 31,835 (19.4%) | 18,978 (22.6%) | 33,649 (20.3%) | ||
≥ 4 | 11,956 (4.8%) | 5092 (6.1%) | 6864 (4.2%) | 5579 (6.7%) | 7817 (4.7%) | ||
Quan-CCI scoref | |||||||
Mean ± SD | 1.0 ± 1.3 | 1.1 ± 1.3 | 0.9 ± 1.2 | 12.00%† | 1.2 ± 1.4 | 1.0 ± 1.3 | 11.87%† |
Other relevant comorbidities, n (%) | |||||||
Cardiac arrhythmia | 223,046 (82.5%) | 75,951 (83.1%) | 147,095 (82.2%) | 2.45% | 76,472 (83.7%) | 147,983 (82.7%) | 2.68% |
Hypertension, uncomplicated | 189,159 (70.0%) | 65,961 (72.2%) | 123,198 (68.8%) | 7.34% | 67,583 (73.9%) | 126,944 (70.9%) | 6.78% |
Hypertension complicated | 27,557 (10.2%) | 10,432 (11.4%) | 17,125 (9.6%) | 6.03% | 11,595 (12.7%) | 18,873 (10.5%) | 6.69% |
Coronary artery disease | 76,563 (28.3%) | 28,713 (31.4%) | 47,850 (26.7%) | 10.33%† | 30,890 (33.8%) | 53,262 (29.8%) | 8.69% |
Peripheral artery disease | 25,000 (9.2%) | 8990 (9.8%) | 16,010 (8.9%) | 3.06% | 9522 (10.4%) | 16,883 (9.4%) | 3.30% |
Hyperlipidemia | 135,582 (50.1%) | 48,069 (52.6%) | 87,513 (48.9%) | 7.42% | 49,929 (54.6%) | 91,597 (51.2%) | 6.94% |
Obesity | 42,114 (15.6%) | 15,768 (17.3%) | 26,346 (14.7%) | 6.92% | 17,163 (18.8%) | 28,974 (16.2%) | 6.83% |
Smoking history | 36,743 (13.6%) | 14,131 (15.5%) | 22,612 (12.6%) | 8.15% | 15,590 (17.1%) | 25,682 (14.3%) | 7.46% |
Strokeh/SE | 1962 (0.7%) | 694 (0.8%) | 1268 (0.7%) | 0.60% | 727 (0.8%) | 1345 (0.8%) | 0.50% |
Strokeh | 1868 (0.7%) | 658 (0.7%) | 1210 (0.7%) | 0.53% | 679 (0.7%) | 1254 (0.7%) | 0.49% |
Medication use during baseline periode | |||||||
Cardiovascular-related medications, n (%) | 262,368 (97.0%) | 89,026 (97.4%) | 173,342 (96.8%) | 3.42% | 89,286 (97.7%) | 174,015 (97.2%) | 3.05% |
Non-oral anticoagulant therapyi | 872 (0.3%) | 367 (0.4%) | 505 (0.3%) | 2.05% | 412 (0.5%) | 610 (0.3%) | 1.75% |
Antihyperlipidemic agentsj | 167,905 (62.1%) | 57,808 (63.2%) | 110,097 (61.5%) | 3.60% | 58,198 (63.7%) | 110,928 (62.0%) | 3.54% |
Antihypertensivesk | 228,893 (84.6%) | 77,985 (85.3%) | 150,908 (84.3%) | 2.85% | 78,312 (85.7%) | 151,976 (84.9%) | 2.21% |
Antiplatelet agentsl | 13,231 (4.9%) | 5063 (5.5%) | 8168 (4.6%) | 4.46% | 4974 (5.4%) | 8526 (4.8%) | 3.09% |
Other cardiovascular medicationsm | 154,738 (57.2%) | 54,727 (59.9%) | 100,011 (55.9%) | 8.13% | 54,960 (60.1%) | 101,132 (56.5%) | 7.38% |
Anti-hyperglycemic agentsn, n (%) | 42,042 (15.5%) | 16,352 (17.9%) | 25,690 (14.4%) | 9.64% | 16,428 (18.0%) | 26,212 (14.6%) | 9.03% |
All-cause healthcare costs during baseline periode,o | |||||||
Total costs (medical + pharmacy) | |||||||
Mean ± SD | $6699 ± $10,437 | $8078 ± $12,057 | $5995 ± $9426 | 19.26%† | $9404 ± $14,836 | $7159 ± $12,201 | 16.53%† |
Total medical costs | |||||||
Mean ± SD | $5048 ± $10,203 | $6108 ± $11,904 | $4507 ± $9167 | 15.07%† | $7448 ± $14,683 | $5680 ± $11,918 | 13.22%† |
Total pharmacy costs | |||||||
Mean ± SD | $1651 ± $1450 | $1970 ± $1236 | $1488 ± $1522 | 34.81%† | $1956 ± $1358 | $1480 ± $1783 | 30.07%† |
Additional beneficiary characteristics | |||||||
Months of follow-upp | |||||||
Mean ± SD | 11.7 ± 1.6 | 11.6 ± 1.7 | 11.7 ± 1.5 | − 4.20% | 11.6 ± 1.7 | 11.7 ± 1.5 | − 4.52% |
Duration of DOAC treatment prior to the index dateq | |||||||
Mean ± SD | 13.3 ± 8.4 | 16.1 ± 10.9 | 11.8 ± 6.3 | 48.37%† | 19.9 ± 12.4 | 13.5 ± 8.3 | 60.52%† |
Month of entering coverage gap, n (%) | 69.23%† | 67.86%† | |||||
January–March | 8726 (3.2%) | 3539 (3.8%) | 5187 (3.0%) | 3637 (4.0%) | 5336 (3.0%) | ||
April–June | 56,720 (20.9%) | 28,637 (31.3%) | 28,083 (15.6%) | 28,828 (31.6%) | 28,046 (15.7%) | ||
July–September | 129,563 (47.9%) | 48,770 (53.3%) | 80,793 (45.2%) | 48,993 (53.5%) | 82,306 (46.0%) | ||
October–December | 75,396 (12.3%) | 10,451 (8.0%) | 64,945 (36.3%) | 9939 (10.9%) | 63,320 (35.4%) |
DOAC Discontinuation Stratified by LIS Status
Proportion of discontinuation, % (n/N) | Adjusted hazard ratioa,b,c (95% CI), p-value | ||
---|---|---|---|
Non-LIS | LIS | Non-LIS vs. LIS | |
DOAC treatment discontinuation during coverage gapd | 18.2% (39,906/218,838) | 10.6% (8999/84,857) | 1.78 (1.73, 1.82), p < 0.001*** |
Incidence of Stroke and Systemic Embolism by DOAC Discontinuation
Doubly robust model-adjusted hazard ratioa,b | 95% CI | p-valuec | |
---|---|---|---|
Composite (ischemic stroke + hemorrhagic stroke + SE) | 1.14 | (1.08, 1.20) | < 0.001*** |
Stroke (ischemic or hemorrhagic) | 1.12 | (1.06, 1.18) | < 0.001*** |
SE | 1.48 | (1.20, 1.82) | < 0.001*** |