TABLE 4.
Multilevel Models of Infant Mortality by Rural-Urban Classification of Resident County, 2014–2016
| Urban-Rural Classification | Model 1a | Model 2a | Model 3a | Model 4a | Model 5b | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| OR | 95% CI | P | OR | 95% CI | P | OR | 95% CI | P | OR | 95% CI | P | OR | 95% CI | P | |
| Total infant deaths | |||||||||||||||
| Metropolitan | |||||||||||||||
| Large metropolitan central | 1.12 | 1.05–1.21 | **** | 1.10 | 1.02–1.18 | *** | 1.09 | 1.02–1.16 | *** | 1.02 | 0.97–1.07 | NS | 1.00 | 0.95–1.05 | NS |
| Large metropolitan fringe | 1.00 | — | 1.00 | — | — | 1.00 | — | — | 1.00 | — | — | 1.00 | — | — | |
| Medium metropolitan | 1.17 | 1.11–1.24 | **** | 1.16 | 1.10–1.22 | **** | 1.09 | 1.04–1.14 | **** | 1.09 | 1.04–1.13 | **** | 1.06 | 1.02–1.10 | *** |
| Small metropolitan | 1.20 | 1.13–1.27 | **** | 1.19 | 1.12–1.26 | **** | 1.08 | 1.02–1.13 | *** | 1.06 | 1.02–1.11 | *** | 1.06 | 1.01–1.11 | * |
| Rural | |||||||||||||||
| Micropolitan | 1.23 | 1.16–1.30 | **** | 1.22 | 1.15–1.29 | **** | 1.04 | 0.99–1.10 | NS | 1.04 | 0.99–1.09 | NS | 1.01 | 0.97–1.06 | NS |
| Noncore (most rural) | 1.28 | 1.20–1.36 | **** | 1.26 | 1.18–1.34 | **** | 1.04 | 0.98–1.10 | NS | 1.03 | 0.97–1.08 | NS | 1.00 | 0.95–1.06 | NS |
| Health care | |||||||||||||||
| HPSA | — | — | — | 1.01 | 0.97–1.05 | NS | — | — | — | 1.03 | 1.00–1.07 | NS | — | — | — |
| FQHC/RHC | — | — | — | 0.99 | 0.95–1.03 | NS | — | — | — | 1.03 | 0.99–1.06 | NS | — | — | — |
| Obstetric hospital | — | — | — | 1.05 | 1.02–1.09 | *** | — | — | — | 1.00 | 0.97–1.02 | NS | — | — | — |
| NICU | — | — | — | 1.09 | 1.04–1.14 | **** | — | — | — | 1.04 | 0.99–1.08 | NS | — | — | — |
| Advantage index | — | — | — | — | — | — | 0.84 | 0.83–0.86 | **** | 0.82 | 0.81–0.84 | **** | — | — | — |
| BIC statistic | 798 137.5 | 798 174.7 | 797 933.6 | 797 658.6 | 618 383.2 | ||||||||||
| Neonatal deaths | |||||||||||||||
| Metropolitan | |||||||||||||||
| Large metropolitan central | 1.14 | 1.05–1.22 | **** | 1.10 | 1.02–1.18 | ** | 1.10 | 1.03–1.18 | *** | 1.01 | 0.96–1.07 | NS | 0.98 | 0.91–1.05 | NS |
| Large metropolitan fringe | 1.00 | — | — | 1.00 | — | — | 1.00 | — | — | 1.00 | — | — | 1.00 | — | — |
| Medium metropolitan | 1.17 | 1.10–1.24 | **** | 1.15 | 1.09–1.22 | **** | 1.10 | 1.04–1.16 | **** | 1.10 | 1.04–1.15 | **** | 1.08 | 1.03–1.14 | *** |
| Small metropolitan | 1.14 | 1.07–1.21 | **** | 1.13 | 1.06–1.20 | **** | 1.04 | 0.99–1.11 | NS | 1.04 | 0.98–1.10 | NS | 1.04 | 0.98–1.11 | NS |
| Rural | |||||||||||||||
| Micropolitan | 1.17 | 1.10–1.24 | **** | 1.17 | 1.10–1.25 | **** | 1.03 | 0.97–1.09 | NS | 1.04 | 0.98–1.10 | NS | 1.03 | 0.96–1.09 | NS |
| Noncore (most rural) | 1.17 | 1.10–1.26 | **** | 1.18 | 1.10–1.26 | **** | 1.00 | 0.94–1.07 | NS | 1.02 | 0.96–1.09 | NS | 1.00 | 0.93–1.08 | NS |
| Health care | |||||||||||||||
| HPSA | — | — | — | 1.03 | 0.99–1.08 | NS | — | — | — | 1.05 | 1.00–1.09 | * | — | — | — |
| FQHC/RHC | — | — | — | 1.01 | 0.97–1.06 | NS | — | — | — | 1.03 | 0.98–1.07 | NS | — | — | — |
| OB hospital | — | — | — | 1.05 | 1.02–1.10 | *** | — | — | — | 1.00 | 0.97–1.04 | NS | — | — | — |
| NICU | — | — | — | 1.07 | 1.01–1.13 | ** | — | — | — | 1.03 | 0.98–1.08 | NS | — | — | — |
| Advantage index | — | — | — | — | — | — | 0.88 | 0.86–0.90 | **** | 0.87 | 0.85–0.89 | **** | — | — | — |
| BIC statistic | 551 437.2 | 551 481.2 | 551 359.5 | 551 284.8 | 415 463.5 | ||||||||||
| Postneonatal Deaths | |||||||||||||||
| Metropolitan | |||||||||||||||
| Large metropolitan central | 1.13 | 1.02–1.24 | ** | 1.13 | 1.02–1.25 | ** | 1.07 | 0.99–1.17 | NS | 1.03 | 0.96–1.10 | NS | 1.03 | 0.97–1.09 | NS |
| Large metropolitan fringe | 1.00 | — | — | 1.00 | — | — | 1.00 | — | — | 1.00 | — | — | 1.00 | — | — |
| Medium metropolitan | 1.20 | 1.11–1.30 | **** | 1.19 | 1.10–1.29 | **** | 1.08 | 1.01–1.16 | * | 1.08 | 1.01–1.14 | ** | 1.02 | 0.97–1.08 | NS |
| Small metropolitan | 1.35 | 1.22–1.48 | **** | 1.34 | 1.22–1.47 | **** | 1.15 | 1.06–1.24 | **** | 1.12 | 1.04–1.20 | *** | 1.08 | 1.02–1.15 | * |
| Rural | |||||||||||||||
| Micropolitan | 1.36 | 1.24–1.49 | **** | 1.34 | 1.22–1.47 | **** | 1.07 | 0.99–1.16 | NS | 1.05 | 0.98–1.12 | NS | 1.00 | 0.93–1.07 | NS |
| Noncore (most rural) | 1.48 | 1.33–1.65 | **** | 1.41 | 1.27–1.58 | **** | 1.10 | 1.01–1.21 | * | 1.03 | 0.95–1.12 | NS | 1.01 | 0.93–1.09 | NS |
| Health care | |||||||||||||||
| HPSA | — | — | — | 0.97 | 0.92–1.03 | NS | — | — | — | 1.01 | 0.96–1.07 | NS | — | — | — |
| FQHC/RHC | — | — | — | 0.96 | 0.91–1.01 | NS | — | — | — | 1.03 | 0.98–1.08 | NS | — | — | — |
| OB hospital | — | — | — | 1.06 | 1.01–1.11 | ** | — | — | — | 1.00 | 0.96–1.04 | NS | — | — | — |
| NICU | — | — | — | 1.12 | 1.04–1.20 | *** | — | — | — | 1.04 | 0.98–1.11 | NS | — | — | — |
| Advantage index | — | — | — | — | — | — | 0.78 | 0.76–0.80 | *** | 0.75 | 0.73–0.77 | *** | — | — | — |
| BIC statistic | 330 663.3 | 330 705.9 | 330 467.8 | 330 266.9 | 266 771.3 | ||||||||||
Model 1 = NCHS category plus county centroids and regional controls. Model 2 = model 1 plus county-level health care factors (HPSA, obstetric hospital, NICU, FQHC/RHC). Model 3 = model 1 plus county-level socioeconomic status (advantage index). Model 4 (full structural model) = model 1+ county-level socioeconomic status (advantage index) plus county population characteristics (fraction white, Black, Hispanic, other; TFR). Model 5 (complete model) = model 4 plus individual-level variables. NS, not significant; —, not applicable.
*
P < .05.
**
P < .01.
***
P < .005.
****
P < .001.
a All models control for county centroid.
b This model excludes Connecticut, Rhode Island, New Jersey, Georgia, Virginia, and Hiawaii and includes all individual level covariates.