Table 3.
Factors that Influence Whether Patients are Initiated on Generic Medications
| Patient characteristics | Relative risk | 95% C.I. lower limit | 95% C.I. upper limit | p-value |
|---|---|---|---|---|
| Males age* | ||||
| 25–39 | 0.50 | 0.37 | 0.67 | 0.001 |
| 40–55 | 0.49 | 0.39 | 0.63 | 0.001 |
| >55 | 0.57 | 0.43 | 0.75 | 0.001 |
| Females age† | ||||
| 25–39 | 1.36 | 1.15 | 1.61 | 0.001 |
| 40–55 | 1.12 | 0.91 | 1.36 | 0.29 |
| >55 | 1.08 | 0.84 | 1.39 | 0.55 |
| Median household income in zip code‡ | ||||
| $30–60,000 | 1.28 | 1.06 | 1.56 | 0.01 |
| >$60,000 | 1.29 | 1.04 | 1.60 | 0.02 |
| Avg. number of prescriptions per month§ | ||||
| 1–3 | 1.17 | 0.86 | 1.59 | 0.32 |
| >3 | 1.27 | 0.93 | 1.74 | 0.14 |
| Pharmacy characteristics// | ||||
| Chain pharmacy | 1.09 | 0.94 | 1.26 | 0.28 |
| Mail-order pharmacy | 1.24 | 0.92 | 1.67 | 0.16 |
| Pharmacy benefit design characteristics¶ | ||||
| No copayments | 0.65 | 0.39 | 1.06 | 0.08 |
| 3 or 4 tiers with lower copayments | 0.97 | 0.75 | 1.26 | 0.83 |
| 3 or 4 tiers with higher copayments | 1.03 | 0.80 | 1.32 | 0.86 |
| Physician characteristics | ||||
| Age# | ||||
| 46–55 | 1.07 | 0.96 | 1.21 | 0.20 |
| >55 | 0.99 | 0.87 | 1.14 | 0.90 |
| Male | 1.03 | 0.92 | 1.16 | 0.58 |
| Specialty** | ||||
| Medical Subspecialist | 0.82 | 0.69 | 0.98 | 0.03 |
| Cardiologist | 0.92 | 0.64 | 1.32 | 0.65 |
| Obstetrics–Gynecology | 0.81 | 0.69 | 0.95 | 0.01 |
| Other | 0.95 | 0.76 | 1.18 | 0.63 |
Results of generalized estimating equations;n = 5,399; controlling for drug class
*Males age 25
†Females age 25
‡Income $30,000
§1 or less avg. prescription filled per month
//Independent pharmacy
¶1 or 2 tier of copayment benefit design;
#Physician age 45 or less
**Generalist physician