Table 3.
Difference-in-Difference Results for Medical Specialties Sub-analysis of Schedule V and PDMP Cohorts. Difference Values Comparing Raw Gabapentin Days Supply for Each Prescriber Group in 2013–2018, and DID Estimates Comparing Control and Intervention Groups After Accounting for Covariates
| Schedule V regulation cohort | Control states (n = 10) |
States exposed to policy (n = 3) |
Difference-in-differences estimate | |||||
|---|---|---|---|---|---|---|---|---|
| 2013 | 2018 | Difference | 2013 | 2018 | Difference | Estimate | 95% CI | |
| Primary care total days per enrollee | 15.60 | 20.57 | 4.96 | 18.09 | 19.97 | 1.87 | − 5.68 | − 7.04 to − 4.31 |
| Anesthesia/pain total days per enrollee | 1.66 | 2.21 | 0.55 | 1.79 | 2.27 | 0.48 | 0.57 | 0.10 to 1.03 |
| Neurology total days per enrollee | 1.50 | 1.64 | 0.14 | 1.73 | 1.59 | − 0.14 | − 0.28 | − 0.44 to − 0.13 |
| Medical & surgical specialties total days per enrollee | 3.08 | 3.59 | 0.51 | 3.30 | 3.29 | − 0.01 | − 0.65 | − 0.95 to − 0.35 |
| Other prescribers total days per enrollee | 2.42 | 6.34 | 3.92 | 5.38 | 9.22 | 3.84 | − 2.20 | − 3.41 to − 0.99 |
| PDMP regulation cohort |
Control states (n = 39) |
States exposed to policy (n = 9) |
Difference-in-differences estimate | |||||
| 2013 | 2018 | Difference | 2013 | 2018 | Difference | Estimate | 95% CI | |
| Primary care total days per enrollee | 12.03 | 16.08 | 4.06 | 12.07 | 15.80 | 3.72 | − 0.73 | − 1.20 to − 0.26 |
| Anesthesia/pain total days per enrollee | 1.12 | 1.47 | 0.35 | 0.90 | 1.13 | 0.23 | − 0.10 | − 0.21 to − 0.012 |
| Neurology total days per enrollee | 1.29 | 1.42 | 0.12 | 1.31 | 1.51 | 0.20 | − 0.04 | − 0.11 to 0.022 |
| Medical & surgical specialties Total days per enrollee | 2.16 | 2.62 | 0.47 | 2.05 | 2.53 | 0.48 | − 0.07 | − 0.18 to 0.040 |
| Other prescriber total days per enrollee | 2.47 | 5.78 | 3.31 | 2.61 | 5.72 | 3.11 | − 0.07 | − 0.42 to 0.29 |