Table 4.
Results of the Instrumental Variables Regression Analysis Estimating the Effect of Primary Care Encounters on Other Types of Service Use and Costs
| Variables† | Specialty Medical Encounters | Specialty Mental Encounters | Physical Health Admits | Mental Health Admits | Outpatient Cost | Inpatient Cost |
|---|---|---|---|---|---|---|
| Intercept | −6.00*** | 1.88 | −0.14 | 0.026 | −7.56*** | −0.55* |
| Primary care encounters | −0.40*** | 0.71 | −0.01 | 0.008 | −0.03 | 0.00 |
| Age | 0.21*** | −0.05 | 0.00 | −0.001 | 0.19*** | 0.01 |
| Age squared | −0.00*** | 0.00 | 0.00 | 0.000* | −0.00*** | 0.00 |
| Male gender | 0.29* | 0.01 | 0.02* | −0.018* | −0.25 | −0.03 |
| Married | 0.09 | −0.13 | −0.01 | 0.023*** | 0.21*** | 0.08* |
| Race | ||||||
| Caucasian (ref.) | ||||||
| African American | −0.26* | 0.20 | −0.03* | −0.027*** | 0.22** | −0.18 |
| Hispanic | −0.13 | 0.22 | −0.03 | −0.026* | 0.38*** | −0.17* |
| Unknown race | −1.44* | −0.28 | −0.08 | −0.045 | −0.72* | −0.28 |
| Percent service connect | −0.13* | −0.07 | 0.00 | −0.000 | 0.03** | −0.00 |
| Means test | ||||||
| Cat A, NSC (ref.) | ||||||
| Cat A, SC | 0.22** | 0.25 | 0.01 | −0.002 | 0.43*** | 0.05 |
| Cat C | −0.65** | 0.35* | −0.05** | 0.002 | −0.79*** | −0.10 |
| Cat NA | 0.12 | −0.52 | 0.03 | −0.001 | −1.17*** | −0.06 |
| DCG risk score | 3.15*** | −2.58** | 0.33*** | −0.156*** | 2.58*** | −0.37 |
| DCG risk score squared | −1.86*** | 1.11* | −0.23*** | 0.048*** | −1.16*** | 0.01 |
| DCG risk score cubed | 0.177*** | −0.12* | 0.02*** | −0.004*** | 0.11*** | −0.01 |
†
Parameter estimates for VISN fixed effects are not displayed.
*
p<.05;
**
p<.01;
***
p<.001.
DCG, Diagnostic Cost Group; VISN, Veterans Integrated Service Networks.