Table 5.
Association between hospital competition and total hospital charge with HHI as a categorical variable
| Surgical Group | ||||
|---|---|---|---|---|
| Prostatectomy | Appendectomy | |||
| Factors | Proportional Change (95% CI) | P Value | Proportional Change (95% CI) | P Value |
| Hospital Competition | ||||
| Insufficient (high concentrated, HHI ≧ 0.25) | 1[Reference] | NA | 1[Reference] | NA |
| Moderate (moderately concentrated, 0.15 < HHI < 0.25) | −0.016 | 0.62 | 0.051 | 0.009 |
| (−0.048, 0.081) | (0.013, 0.089) | |||
| High (unconcentrated, HHI ≦0.15) | −0.642 | < 0.001 | 0.090 | < 0.001 |
| (−1.019, −0.265) | (0.046, 0.134) | |||
| Control Variablesa | Yes | Yes | ||
Abbreviations: NA not applicable, HHI Herfindahl-Hirschman Index; CI confidence interval
aControl variables: gender, age, occupation, insurance, admission severity, whether in critical condition, admission approach, length of stay, hospital classification, hospital level, profit and ownership classification, urbanization rate, GDP per capita and a set of county dummies