Table 2.
Changes in Monthly Part D and Antipsychotic Spending and Adherence After Reaching the Gap Threshold
| Standard Gap | No Gap (LIS) | Gap – No Gap | ||||
|---|---|---|---|---|---|---|
|
| ||||||
| Schizophrenia | Diff | 95% CI | Diff | 95% CI | Diff | 95% CI |
| Total Part D spending ($) | −171 | (−187, −155) | 14 | (3, 26) | −186 | (−205, −166) |
| Total antipsychotic spending ($) | −116 | (−128, −104) | 6 | (−2, 15) | −123 | (−138, −108) |
| Out-of-pocket Part D spending ($) | 235 | (229, 242) | 2 | (−3, 6) | 234 | (226, 242) |
| Out-of-pocket antipsychotic spending ($) | 104 | (99, 109) | 0 | (−3, 4) | 104 | (98, 110) |
| Proportion of days covered (percentage points) | −19.8 | (−21.2, −18.4) | 0.9 | (−0.1, 1.8) | −20.6 | (−22.3, −18.9) |
|
| ||||||
| Bipolar disorder | Diff | 95% CI | Diff | 95% CI | Diff | 95% CI |
|
| ||||||
| Total Part D spending ($) | −170 | (−184, −156) | 27 | (14, 40) | −197 | (−216, −178) |
| Total antipsychotic spending ($) | −86 | (−95, −78) | 7 | (−1, 15) | −93 | (−105, −82) |
| Out-of-pocket Part D spending ($) | 216 | (210, 223) | 2 | (−4, 8) | 214 | (206, 223) |
| Out-of-pocket antipsychotic spending ($) | 64 | (61, 68) | 0 | (−3, 3) | 64 | (59, 69) |
| Proportion of days covered (percentage points) | −20.5 | (−21.9, −19.2) | −2.4 | (−3.8, −1.1) | −18.1 | (−20.0, −16.2) |
|
| ||||||
| No Mental Health Diagnosis | Diff | 95% CI | Diff | 95% CI | Diff | 95% CI |
|
| ||||||
| Total Part D spending ($) | −108 | (−125, −91) | 20 | (4, 37) | −128 | (−152, −105) |
| Total antipsychotic spending ($) | −32 | (−41, −24) | 3 | (−5, 12) | −36 | (−48, −24) |
| Out-of-pocket Part D spending ($) | 227 | (219, 236) | 1 | (−8, 9) | 227 | (215, 239) |
| Out-of-pocket antipsychotic spending ($) | 57 | (53, 61) | −1 | (−5, 4) | 57 | (51, 63) |
| Proportion of days covered (percentage points) | −13.7 | (−15.5, −12.0) | −2.8 | (−4.5, −1.0) | −11.0 | (−13.4, −8.5) |
Notes: To examine changes in drug spending and adherence (PDC), we used linear fixed effects regression models (xtreg, fe in Stata 10). Because the average days supply of an antipsychotic prescription was 30 days, we examined separately the first month after reaching the gap (transition period), and ≥ 31 days after reaching the gap; these tables report the post-transition period, after beneficiaries would have been more likely to have exhausted any existing drug supply from fills dispensed prior to or at the point of reaching the gap. The models included indicators for these two gap periods and interactions between these indicators and an indicator for having a coverage gap vs. no gap due to the LIS. We censored outcomes during the catastrophic coverage period for subjects who reached it. Mean values of the outcomes during the pre-gap period are available in the online appendix (A2).