Table 5.
Adjusted analyses for prolonged length of stay and high readmission costs
| Prolonged length of stay | High costs | |||
|---|---|---|---|---|
| aRR | 95% CI | aRR | 95% CI | |
| Readmission to hospital other than delivery hospital | 1.48 | 1.42, 1.54 | 1.74 | 1.67, 1.81 |
| Maternal age | ||||
| 15–19 years old | 1.08 | 1.01, 1.15 | 0.89 | 0.83, 0.95 |
| 20–24 years old | 1.03 | 0.98, 1.08 | 0.94 | 0.89, 0.99 |
| 25–29 years old | Reference | Reference | ||
| 30–34 years old | 0.98 | 0.93, 1.02 | 1.04 | 0.99, 1.09 |
| 35–39 years old | 1.00 | 0.94, 1.06 | 1.08 | 1.02, 1.14 |
| 40–54 years old | 0.92 | 0.84, 1.01 | 1.19 | 1.10, 1.30 |
| Payer | ||||
| Medicare | 1.82 | 1.62, 2.05 | 1.74 | 1.54, 1.95 |
| Medicaid | 1.44 | 1.38, 1.50 | 1.25 | 1.20, 1.30 |
| Private insurance | Reference | Reference | ||
| Self-pay | 1.57 | 1.37, 1.80 | 1.26 | 1.09, 1.47 |
| No charge | 1.12 | 0.53, 2.38 | 1.06 | 0.50, 2.23 |
| Other | 1.17 | 1.05, 1.31 | 1.01 | 0.91, 1.13 |
| Median ZIP code income quartile | ||||
| Lowest income quartile | 1.28 | 1.21, 1.35 | 0.97 | 0.92, 1.02 |
| 2nd lowest quartile | 1.11 | 1.04, 1.17 | 0.94 | 0.89, 0.99 |
| 2nd highest quartile | 1.10 | 1.04, 1.16 | 0.93 | 0.88, 0.98 |
| Highest income quartile | Reference | Reference | ||
| Delivery postpartum hemorrhage | 1.10 | 1.02, 1.18 | 1.44 | 1.34, 1.53 |
| Cesarean delivery | 1.74 | 1.68, 1.80 | 1.39 | 1.34, 1.44 |
| Pregestational diabetes | 1.42 | 1.30, 1.55 | 1.44 | 1.32, 1.58 |
| Gestational diabetes | 1.11 | 1.05, 1.18 | 1.04 | 0.98, 1.10 |
| Systemic lupus erythematosus | 1.47 | 1.19, 1.81 | 1.63 | 1.34, 1.99 |
| Multiple gestation | 1.03 | 0.95, 1.12 | 1.10 | 1.02, 1.20 |
| Asthma | 1.07 | 1.00, 1.15 | 1.10 | 1.03, 1.18 |
| Chronic kidney disease | 1.34 | 1.15, 1.56 | 1.38 | 1.19, 1.61 |
| Hypertensive diseases of pregnancy | 0.84 | 0.81, 0.88 | 0.86 | 0.82, 0.90 |
| Chronic hypertension | 1.01 | 0.94, 1.10 | 0.87 | 0.80, 0.95 |
| Hospital bed size | ||||
| Small | Reference | Reference | ||
| Medium | 1.05 | 0.98, 1.13 | 0.82 | 0.77, 0.87 |
| Large | 1.21 | 1.14, 1.29 | 0.89 | 0.84, 0.94 |
| Hospital teaching status | ||||
| Metropolitan non-teaching | Reference | Reference | ||
| Metropolitan teaching | 1.02 | 0.98, 1.06 | 0.94 | 0.90, 0.97 |
| Non-metropolitan | 0.81 | 0.76, 0.86 | 1.02 | 0.96, 1.08 |
aRR, adjusted risk ratio. CI, confidence interval. Estimates for medical and obstetric conditions are with absence of the condition as the reference. For the fragmentation variable, hospital where delivery occurred is the reference. High readmission costs were defined as >90th percentile or ≥$13,720.27. Prolonged lengths of stay were defined as >90th percentile or ≥6 days. All variables in the table were included in the adjusted analysis.