Table 4.
Adherence, Out-of-Pocket Costs and Switching Rates, By Physician Prescribing
| a. Predicted MPR within the class within six months of the initial prescription | |||||
|---|---|---|---|---|---|
|
| |||||
| Degree of narrow (concentrated) prescribing. | Statins | PPIs | SSRI/SNRI | Antihistamines | Calcium Channel Blockers |
| High | 0.77 | 0.58*** | 0.66 | 0.35*** | 0.77 |
| Medium | 0.76 | 0.60 | 0.66 | 0.37 | 0.76 |
| Low | 0.75* | 0.61 | 0.66 | 0.37 | 0.76 |
| Total Average MPR | 0.76 | 0.60 | 0.66 | 0.36 | 0.77 |
| N | 60,366 | 42,057 | 36,039 | 32,191 | 10,844 |
| Degree of narrow (concentrated) prescribing. | b. Predicted Annual Copay (Patient Cost of One Year’s Supply) within the class | ||||
|---|---|---|---|---|---|
|
| |||||
| Statins | PPIs | SSRI/SNRI | Antihistamines | Calcium Channel | |
| High | $144.03*** | $208.51 | $146.94 | $177.68* | $123.97** |
| Medium | $139.77 | $208.51 | $145.47 | $170.72 | $116.75 |
| Low | $139.77 | $214.86** | $141.17* | $179.467** | $108.85*** |
| Mean Avg Annual Copay | $141.17 | $210.61 | $144.03 | $175.91 | $116.75 |
| N | 41,566 | 26,508 | 31,163 | 18,767 | 8,715 |
| c. Predicted Switching within the class during six months after the initial prescription | |||||
|---|---|---|---|---|---|
|
| |||||
| Statins | PPIs | SSRI/SNRI | Antihistamines | Channel Blockers | |
| High | 0.10 | 0.19 | 0.20 | 0.15 | 0.19* |
| Medium | 0.10 | 0.18 | 0.20 | 0.15 | 0.21 |
| Low | 0.12*** | 0.18 | 0.22** | 0.14 | 0.20 |
| Total Probability of Switching | 0.11 | 0.18 | 0.21 | 0.15 | 0.20 |
|
| |||||
| N | 41,621 | 19,930 | 20,436 | 6,585 | 7,594 |
Notes: Dependent variable is calculated as total daily doses purchased within 180 days of initial prescription, divided by 180. Categories of narrowness are tertiles of the percent deviation of each doctor’s number of drugs prescribed from predicted number of drugs prescribed.
Asterisks reflect statistical signifcance at the 1% (***), 5% (**) and 10% (*)
Notes: Dependent variable is calculated as the year-equivalent total copay amount, based on the average copay payment per daily dose in the six months following the initial prescription. To capture plan formulary characteristics, we control for the mean brand copay in the class for each patient’s plan, as well as the mean copay difference between brand and generic drugs. We exclude plans in which these values could not be determined (see Appendix).
Asterisks reflect statistical signifcance at the 1% (***), 5% (**) and 10% (*) level relative to Medium prescribing.
Notes: Dependent variable is binary, equal to 1 if the patient is observed to fill a prescription for another drug in the class, written by the same prescriber as the initial prescription, within six months following the initial prescription. For this analysis, we exclude patients who discontinue therapy in the class within the first six months, and we control for the drug initially prescribed.
Asterisks reflect statistical signifcance at the 1% (***), 5% (**) and 10% (*) level relative to Medium prescribing.