Table 3.
The Impact of Coverage Gap on Heart Failure Medication Use and Spending among Elderly Beneficiaries Diagnosed with Depression in 2007
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|---|---|---|---|---|---|---|---|
| Unadjusted Data* | Diff-in-Diff Coverage Gap Effect† | % Change, Diff-in-Diff Effects/Pre-Gap Values‡ | |||||
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| Pre-Gap | Within-Gap | Estimate | 95% CI | % | 95% CI | ||
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Probability of Using a Drug
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| All | No-coverage | 0.88 | 0.72 | −0.05 | (−0.05, −0.04) | −5.2 | (−6.2, −4.2) |
| Generic-only | 0.91 | 0.80 | −0.04 | (−0.05, −0.03) | −4.6 | (−5.7, −3.6) | |
| LIS | 0.90 | 0.82 | Reference | ||||
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| Brand-name | No-coverage | 0.65 | 0.40 | −0.05 | (−0.07, −0.04) | −8.2 | (−10.1, −6.3) |
| Generic-only | 0.66 | 0.45 | −0.06 | (−0.08, −0.05) | −9.7 | (−11.8, −7.6) | |
| LIS | 0.60 | 0.42 | Reference | ||||
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| Generics | No-coverage | 0.75 | 0.64 | −0.02 | (−0.03, −0.01) | −2.3 | (−3.7, −1.0) |
| Generic-only | 0.79 | 0.73 | −0.02 | (−0.03, −0.01) | −2.2 | (−3.6, −0.7) | |
| LIS | 0.81 | 0.75 | Reference | ||||
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No. of Monthly Prescriptions
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| All | No-coverage | 1.79 | 1.33 | −0.23 | (−0.26, −0.20) | −12.9 | (−14.7, −11.2) |
| Generic-only | 2.04 | 1.63 | −0.18 | (−0.21, −0.14) | −8.7 | (−10.4, −7.0) | |
| LIS | 1.90 | 1.66 | Reference | ||||
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| Brand-name | No-coverage | 0.71 | 0.36 | −0.15 | (−0.17, −0.13) | −21.1 | (−23.4, −18.7) |
| Generic-only | 0.78 | 0.40 | −0.14 | (−0.16, −0.13) | −18.6 | (−21.1, −16.2) | |
| LIS | 0.61 | 0.39 | Reference | ||||
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| Generics | No-coverage | 1.08 | 0.97 | −0.08 | (−0.11, −0.06) | −7.6 | (−10.0, −5.1) |
| Generic-only | 1.27 | 1.23 | −0.03 | (−0.06, 0.00) | −2.6 | (−4.9, −0.2) | |
| LIS | 1.29 | 1.27 | Reference | ||||
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Monthly Pharmacy Spending
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| All | No-coverage | 65 | 40 | −12.10 | (−13.38, −10.82) | −18.7 | (−20.7, −16.7) |
| Generic-only | 72 | 47 | −11.39 | (−12.86, −9.92) | −15.8 | (−17.8, −13.7) | |
| LIS | 62 | 49 | Reference | ||||
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| Brand-name | No-coverage | 49 | 25 | −10.44 | (−11.64, −9.25) | −21.5 | (−24.0, −19.1) |
| Generic-only | 53 | 27 | −10.26 | (−11.64, −8.88) | −19.5 | (−22.1, −16.9) | |
| LIS | 43 | 28 | Reference | ||||
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| Generics | No-coverage | 16 | 15 | −1.66 | (−2.23, −1.08) | −10.3 | (−13.9, −6.7) |
| Generic-only | 20 | 20 | −1.13 | (−1.81, −0.45) | −5.8 | (−9.3, −2.3) | |
| LIS | 20 | 21 | Reference | ||||
*
These are average numbers in the pre-gap and within-gap periods, but they are unadjusted raw data.
†
“Diff-in-Diff Coverage Gap Effects” are adjusted estimates from the difference-in-difference model with the inverse of propensity score as a weight. The estimates measure changes in outcomes between within-gap and pre-gap periods in each study group, relative to the changes in outcomes in the comparison group (“Reference”).
‡
“% Change” is calculated using “Diff-in-Diff Coverage Gap Effects” divided by pre-gap values. Abbreviations: LIS = low-income-subsidies; this is the comparison group.