Table 2.
Marginal Effects of Selected Variables on Statin Compliance (PDC ≥80%)
| Variable | Marginal Effect (Standard Error) | |
|---|---|---|
| Enrollees with Gap Coverage | Enrollees without Gap Coverage | |
| Effective price ($) | −0.367 (0.197)* | −0.469 (0.218)** |
| Age | −0.032 (0.047) | 0.128 (0.056)** |
| Female | −3.008 (0.557)*** | −1.819 (0.736)** |
| White | 6.464 (0.903)*** | 9.560 (1.001)*** |
| Prescription drug hierarchical chronic condition (RxHCC) score | −2.039 (1.126)* | −3.247 (1.430)** |
| Number of therapeutic classes of drugs taken in the prior year | 0.857 (0.130)*** | 0.918 (0.218)*** |
| Chronic obstructive pulmonary disease | −0.643 (0.957) | −1.142 (1.188) |
| Diabetes | 2.196 (0.671)*** | 1.950 (0.903)** |
| Major depression | −2.728 (1.732) | −0.327 (2.337) |
| Cardiovascular disease | 0.181 (0.844) | 0.153 (1.006) |
| % of fills prescribed by primary care providers | 1.929 (0.827)** | 1.807 (0.998)* |
| Plan type | ||
| Private fee-for-service (ref.) | ||
| Health maintenance organization | −1.079 (1.603) | 1.202 (1.623) |
| Preferred provider organization | 5.945 (1.895)*** | 2.622 (2.201) |
| Number of enrollees of a plan | 0.000 (0.000)*** | 0.000 (0.000) |
| Percent college educated | 0.071 (0.024)*** | 0.082 (0.033)** |
| Median household income | ||
| Less than $35,000 (ref.) | ||
| $35,000 to $50,000 | 2.486 (0.795)*** | 1.562 (0.928)* |
| More than $50,000 | 5.605 (1.078)*** | 3.33 (1.231)** |
Corrected for sample-selectivity associated with choosing gap coverage.
The difference between the two groups was statistically significant: χ2 = 98.87 based on a test from seemingly unrelated estimation; F = 15.96 from a Chow test based on linear probability models.
*
p < .1
**
p < .05
***
p < .01.
PDC, proportion of days covered.