Table 3.
Propensity-weighted, adjusted differences in utilization of care between pilot and comparison practices among continuously enrolled patients (n=10548 pilot and n=6815 comparison patients).
| Pilot | Comparison | Difference (95% CI) | P value | |
|---|---|---|---|---|
| Hospitalizations, all-cause | Rate per 1000 patients per month (95% CI)* | |||
| Pre-intervention | 7.0 | 7.0 | NA** | NA |
| Intervention year 1 | 7.3 | 8.8 | −1.5 (−3.1, 0.2) | 0.069 |
| Intervention year 2 | 7.4 | 9.2 | −1.8 (−3.3, −0.2) | 0.001 |
| Intervention year 3 | 8.5 | 10.2 | −1.7 (−3.2, −0.03) | 0.006 |
| Hospitalizations, ambulatory care-sensitive | ||||
| Pre-intervention | 0.5 | 0.5 | NA | NA |
| Intervention year 1 | 0.5 | 0.7 | −0.2 (−0.6, 0.2) | 0.21 |
| Intervention year 2 | 0.8 | 0.9 | −0.1 (−0.5, 0.4) | 0.67 |
| Intervention year 3 | 0.8 | 1.0 | −0.2 (−0.6, 0.3) | 0.52 |
| ED visits, all-cause | ||||
| Pre-intervention | 23.9 | 23.9 | NA | NA |
| Intervention year 1 | 24.5 | 27.5 | −3.0 (−6.6, 0.5) | 0.090 |
| Intervention year 2 | 26.3 | 28.4 | −2.1 (−5.6, 1.1) | 0.29 |
| Intervention year 3 | 29.5 | 34.2 | −4.7 (−8.7, −0.9) | 0.001 |
| ED visits, ambulatory care-sensitive | ||||
| Pre-intervention | 13.5 | 13.5 | NA | NA |
| Intervention year 1 | 13.5 | 15.0 | −1.4 (−3.8, 1.1) | 0.11 |
| Intervention year 2 | 14.5 | 15.6 | −1.2 (−3.8, 1.3) | 0.16 |
| Intervention year 3 | 16.2 | 19.4 | −3.2 (−5.7, −0.9) | <0.001 |
| Pre-intervention | 379.6 | 379.6 | NA** | NA |
| Intervention year 1 | 357.0 | 304.2 | 52.8 (9.1, 99.4) | 0.024 |
| Intervention year 2 | 357.1 | 250.0 | 107 (51.1, 178.5) | 0.002 |
| Intervention year 3 | 349.0 | 271.5 | 77.5 (37.3, 120.5) | 0.001 |
| Ambulatory visits, specialist | ||||
| Pre-intervention | 106.2 | 106.2 | NA | NA |
| Intervention year 1 | 108.7 | 117.3 | −8.7 (−16.2, −1.2) | 0.01 |
| Intervention year 2 | 104.8 | 121.3 | −16.5 (−27.5, −5.9) | <0.001 |
| Intervention year 3 | 104.9 | 122.2 | −17.3 (−26.6, −8.0) | <0.001 |
Abbreviations: NA, Not Applicable; CI, confidence interval.
Point estimates for utilization and utilization differences are propensity-weighted recycled predictions from two-part logistic and negative binomial regression models adjusting for baseline utilization rates; patient gender, age, Charlson comorbidity score; health plan contributing each observation, and whether each patient was in an HMO product at the time of the observation. Confidence intervals are bootstrap estimates from these two-part models; p-values are from one-part negative binomial regression models.
Due to the inclusion of fixed effects for practices, regression models do not estimate pre-intervention differences between pilot and comparison.
For primary care visits, only one-part negative binomial models converged (because, due to attribution methods, no patients had zero primary care visits in the pre-intervention period).