TABLE 4.
Multivariable Negative Binomial Regression Model of Factors Associated With Length of Stay
| Variable | 1997 IRR (95% CI) |
2000 IRR (95% CI) |
2003 IRR (95% CI) |
2006 IRR (95% CI) |
|---|---|---|---|---|
| Age category | ||||
| <1 year | … | … | … | … |
| 1–5 years | 0.82 (0.81, 0.84)‡ | 0.83 (0.88, 0.95)‡ | 0.86 (0.85, 0.88)‡ | 0.87 (0.86, 0.89)‡ |
| 6–11 years | 0.91 (0.87, 0.95) ‡ | 0.91 (0.88, 0.94)‡ | 0.93 (0.91, 0.95)‡ | 0.93 (0.90, 0.95)‡ |
| >12 years | 1.03 (0.99, 1.07) | 1.17 (1.11, 1.22)‡ | 1.09 (1.06, 1.13)‡ | 1.13 (1.09, 1.16)‡ |
| Race | ||||
| White | … | … | … | … |
| Black | 1.04 (0.99, 1.08) | 1.00 (0.95, 1.03) | 1.00 (0.98, 1.03) | 1.02 (0.98, 1.06) |
| Other | 1.09 (1.05, 1.13)† | 1.11 (1.08, 1.15)‡ | 1.09 (1.06, 1.12)‡ | 1.08 (1.05, 1.11)‡ |
| Missing | 1.00 (0.94, 1.06) | 1.01 (0.96, 1.06) | 0.95 (0.92, 0.99)* | 0.96 (0.93, 0.99)† |
| Sex | ||||
| Female | 1.02 (0.94, 1.06) | 1.01 (0.99, 1.02) | 1.01(0.93, 100) | 1.01 (1.00, 1.02) |
| Insurance type | ||||
| Private | … | … | … | … |
| Public | 1.13 (1.11, 1.16)‡ | 1.11 (1.09, 1.14)‡ | 1.11 (1.09, 1.13)‡ | 1.11 (1.09, 1.13)‡ |
| Uninsured | 1.01 (0.91, 1.11) | 0.93 (0.89, 0.96)‡ | 0.92 (0.90, 0.96)‡ | 0.94 (0.91, 0.96)‡ |
| Other | 1.01 (0.96, 1.06) | 1.10 (1.03, 1.18)† | 1.10 (1.02, 1.19)* | 1.07 (1.02, 1.13)† |
| Hospital type | ||||
| Urban non-teaching | … | … | … | … |
| Rural | 0.98 (0.92, 1.04) | 0.96 (0.92, 1.00) | 0.97 (0.94, 1.00)† | 0.97 (0.93, 1.00) |
| Urban teaching (non-children’s) | 0.99 (0.95, 1.04) | 1.06 (1.02, 1.10)† | 1.06 (1.02, 1.10) ‡ | 1.03 (0.99, 1.07) |
| Urban teaching children’s | 1.2 (1.14, 1.26)‡ | 1.23 (1.16, 1.30)‡ | 1.28 (1.21, 1.37)‡ | 1.25 (1.19, 1.31)‡ |
| Region | ||||
| Northeast | … | … | … | … |
| Midwest | 0.93 (0.88, 0.98)* | 0.96 (0.92, 1.00) | 0.95 (0.91, 0.99)* | 0.95 (0.91, 0.99)* |
| South | 0.98 (0.94, 1.02) | 1.06 (1.02, 1.10)* | 1.04 (1.00, 1.09) | 1.03 (0.98, 1.08) |
| West | 0.97 (0.92, 1.01) | 1.22 (1.16, 1.30)* | 1.02 (0.97, 1.08) | 1.06 (1.00, 1.12)* |
| Transfer status | ||||
| Transfer | 1.35 (1.25, 1.46)‡ | 1.39 (1.27, 1.52)‡ | 1.31 (1.23, 1.37 ) | 1.16 (1.10, 1.23)‡ |
| Asthma | 0.99 (0.96, 1.03) | 0.97 (0.95, 0.99)† | 0.98 (0.96, 1.00) | 0.98 (0.97, 1.00)* |
| Pneumonia Complications | 0.99 (0.96, 1.03) | 0.97 (0.95, 0.99)* | 0.98 (0.96, 1.0) | 0.98 (0.97, 1.00)* |
| Any complication | 2.20 (2.07, 2.34)‡ | 2.23 (2.07, 2.40)‡ | 2.22 (2.22, 2.44)‡ | 2.37 (2.27, 2.47)‡ |
NOTE: All available variables included in multivariable models. KID categorizes states into the following 4 regions: Northeast (Connecticut, Maine, Massachusetts, New Hampshire, New Jersey, New York, Pennsylvania, Rhode Island, Vermont); Midwest (Illinois, Indiana, Iowa, Kansas, Michigan, Minnesota, Missouri, Nebraska, North Dakota, Ohio, South Dakota, Wisconsin); South (Alabama, Arkansas, Delaware, District of Columbia, Florida, Georgia, Kentucky, Louisiana, Maryland, Mississippi, North Carolina, Oklahoma, South Carolina, Tennessee, Texas, Virginia, West Virginia); West (Alaska, Arizona, California, Colorado, Hawaii, Idaho, Montana, Nevada, New Mexico, Oregon, Utah, Washington, Wyoming). Abbreviations: CI, confidence interval; IRR, incidence rate ratio. Significant values are noted as follows; all other values are not significant:
P < 0.05;
P < 0.01;
P < 0.001.