Table 3.
Multivariable Correlates of Cost-related Medication Skipping in 1998 and 2000*
| 1998 | 2000 | P Value for Change§ | |||
|---|---|---|---|---|---|
| OR [95% CI] | P Value | OR [95% CI] | P Value | ||
| Monthly medication costs ($ per month) | <.0001 | ||||
| $0 | Reference group | Reference group | |||
| $1 to $24 | 1.3 [0.74, 2.3] | .34 | 1.5 [0.74, 3.1] | .26 | |
| $25to $49 | 1.6 [0.9, 2.8] | .11 | 4.1 [2.1, 8.3] | .0001 | |
| $50 to $99 | 3.2 [1.8, 5.7] | .0001 | 6.0 [3.0, 12] | <.0001 | |
| $100 to $199 | 4.0 [2.1, 7.4] | <.0001 | 11 [5.5, 24] | <.0001 | |
| $200 and greater | 6.1 [2.9, 12.9] | <.0001 | 16 [7.4, 35] | <.0001 | |
| Lowest quartile of physician-patient relationship quality† | 2.2 [1.4, 3.4] | .001 | 2.1 [1.4, 3.2] | .0003 | .007 |
| Low income | 2.2 [1.6, 3.0] | <.0001 | 1.4 [1.0, 2.0] | .04 | .96 |
| No prescription medication coverage | 1.8 [1.3, 2.4] | .0001 | 1.7 [1.3, 2.3] | .0001 | .89 |
| Age† | 0.61 [0.49, 0.76] | <.0001 | 0.54 [0.42, 0.69] | <.0001 | .38 |
| Physical component scale‡ | 0.69 [0.60, 0.79] | <.0001 | 0.77 [0.66, 0.89] | .0005 | .09 |
| Mental component scale‡ | 0.67 [0.58, 0.77] | <.0001 | 0.73 [0.64, 0.83] | <.0001 | .03 |
| HMO member | 1.0 [0.80, 1.3] | .84 | 1.5 [1.2, 2.0] | .0004 | .001 |
| Disease count | 0.94 [0.86, 1.02] | .12 | 0.99 [0.91, 1.1] | .83 | .16 |
| Number of prescriptions | 0.97 [0.91, 1.02] | .25 | 0.99 [0.92, 1.1] | .85 | .31 |
| Inpatient stay | 0.91 [0.65, 1.3] | .58 | 0.93 [0.63, 1.4] | .73 | .43 |
| Outpatient visits | 0.98 [0.89, 1.1] | .75 | 0.91 [0.81, 1.02] | .11 | .60 |
| Female | 1.0 [0.77, 1.3] | .96 | 0.89 [0.67, 1.2] | .42 | .38 |
| Caucasian race | 0.98 [0.67, 1.4] | .90 | 1.2 [0.82, 1.7] | .35 | .22 |
| High school education | 0.97 [0.91, 1.03] | .33 | 0.93 [0.89, 0.98] | .008 | .03 |
| Married | 1.04 [0.77, 1.4] | .79 | 0.76 [0.56, 1.03] | .08 | .50 |
*
We applied sampling weights to all results to correct for difference in sampling probabilities across the strata. The observed sample size was 7,130 for 1998 and 4,630 for 2000
†
Reference group is the top quartile of the physician-patient relationship score
‡
The OR is the odds of reporting cost-related medication skipping for each 10-point improvement in physical or mental health, and each 10-year increment in age
§
P value for the change in the OR from 1998 to 2000, using seemingly unrelated regression method
OR, odds ratio; CI, confidence interval