Table 3.
Linear Fixed Effects Models of Retail and Mail Prescription Drug Utilization† (N=1,074)
| Variable | Number of Retail rxs PMPQ | Number of Mail rxs PMPQ | Mail Distribution Rate (MDR) |
|---|---|---|---|
| Two-tier member cost sharing‡ | |||
| Retail coinsurance | −0.24809*** | 0.03542 | 0.04002*** |
| (0.06691) | (0.07997) | (0.01090) | |
| Retail generic OOP cost | 0.05502 | 0.07340*** | −0.00041 |
| (0.03934) | (0.02619) | (0.00446) | |
| Retail generic OOP cost squared | −0.00435* | −0.00124 | 0.00070** |
| (0.00234) | (0.00147) | (0.00028) | |
| Retail brand OOP cost | −0.02957*** | 0.00263 | 0.00139 |
| (0.00607) | (0.00346) | (0.00100) | |
| Retail brand OOP cost squared | 0.00039*** | −0.00011** | −0.00003* |
| (0.00011) | (0.00005) | (0.00002) | |
| Mail–retail generic OOP cost ratio | 0.13557*** | 0.02756 | −0.01021* |
| (0.04438) | (0.07736) | (0.00528) | |
| Mail–retail generic OOP cost ratio squared | −0.01581*** | −0.00256 | 0.00190** |
| (0.00447) | (0.00792) | (0.00074) | |
| Mail–retail brand OOP cost ratio | −0.20627*** | −0.29181*** | −0.04426*** |
| (0.04160) | (0.06907) | (0.01321) | |
| Mail–retail brand OOP cost ratio squared | 0.01168*** | 0.01314*** | 0.00170** |
| (0.00192) | (0.00367) | (0.00069) | |
| Three-tier member cost sharing§ | |||
| Retail coinsurance | 0.04413 | −0.08987 | −0.01150* |
| (0.07548) | (0.05907) | (0.00669) | |
| Retail generic OOP cost | −0.00863 | −0.02178*** | −0.00502*** |
| (0.01246) | (0.00545) | (0.00095) | |
| Retail generic OOP cost squared | −0.00010 | 0.00056*** | 0.00020*** |
| (0.00023) | (0.00008) | (0.00003) | |
| Retail P brand OOP cost | −0.02413 | 0.05051*** | 0.01026*** |
| (0.01643) | (0.01707) | (0.00160) | |
| Retail P brand OOP cost squared | 0.00004 | −0.00086*** | −0.00015*** |
| (0.00028) | (0.00027) | (0.00002) | |
| Retail NP brand OOP cost | 0.00945 | −0.01553*** | −0.00244*** |
| (0.00679) | (0.00601) | (0.00051) | |
| Retail NP brand OOP cost squared | −0.00004 | 0.00009** | 0.00001*** |
| (0.00006) | (0.00004) | (0.00000) | |
| Mail–retail generic OOP cost ratio | 0.03622 | 0.00454 | −0.00553*** |
| (0.02406) | (0.01779) | (0.00160) | |
| Mail–retail generic OOP cost ratio squared | −0.00229*** | −0.00207 | −0.00000 |
| (0.00084) | (0.00146) | (0.00016) | |
| Mail–retail P brand OOP cost ratio | 0.17569 | −0.69608*** | −0.08708*** |
| (0.28698) | (0.24399) | (0.00843) | |
| Mail–retail P brand OOP cost ratio squared | −0.03378 | 0.15397** | 0.02119*** |
| (0.06491) | (0.06794) | (0.00443) | |
| Mail–retail NP brand OOP cost ratio | −0.50486* | 0.41969*** | 0.08572*** |
| (0.30047) | (0.10726) | (0.01556) | |
| Mail–retail NP brand OOP cost ratio squared | 0.10245** | −0.11496*** | −0.02268*** |
| (0.04926) | (0.02967) | (0.00409) | |
| Other pharmacy benefit design elements | |||
| Retail deductible | −0.10245** | −0.17318*** | −0.02317*** |
| (0.04156) | (0.02766) | (0.00372) | |
| Retail dispense as written penalty (physician) | −0.13314*** | 0.08707*** | 0.04351*** |
| (0.02987) | (0.03039) | (0.00701) | |
| Retail dispense as written penalty (patient) | −0.05743 | 0.19050*** | 0.04367*** |
| (0.04050) | (0.06432) | (0.00864) | |
| Retail maximum allowable benefit | 0.01071 | 0.11482*** | 0.01881*** |
| (0.03463) | (0.03229) | (0.00666) | |
| Retail maximum out-of-pocket | 0.01930 | −0.15155 | −0.00866 |
| (0.11792) | (0.12804) | (0.00613) | |
| Mandatory mail | −0.26787*** | 0.28661*** | 0.08597*** |
| (0.02059) | (0.02914) | (0.00855) | |
Notes: Presented are coefficient estimates with robust Driscoll–Kraay standard errors in parentheses.
Included in models but not reported are 11 plan sponsor characteristic variables, 11 time dummies, and a constant.
Statistical significance denoted as:
p<.01.
p<.05.
p<.10.
Prescription drug utilization measures calculated using 30-day supply equivalents (i.e., 1 mail rx=3 retail rxs).
Coefficients and standard errors are of member cost-sharing variables interacted with two-tier plan indicator.
Coefficients and standard errors are of member cost-sharing variables interacted with three-tier plan indicator.
NP brand, nonpreferred brand; OOP, out-of-pocket; P brand, preferred brand; PMPQ, per member per quarter.