Table 4.
Unadjusted and adjusted analysis for severe maternal morbidity during postpartum readmission
| Unadjusted model | Adjusted model | |||
|---|---|---|---|---|
| RR | 95% CI | aRR | 95% CI | |
| Readmission to hospital other than delivery hospital | 1.84 | 1.79, 1.89 | 1.81 | 1.76, 1.86 |
| Maternal age | ||||
| 15–19 years old | 1.02 | 0.97, 1.07 | 0.96 | 0.92, 1.01 |
| 20–24 years old | 1.03 | 0.99, 1.06 | 0.97 | 0.94, 1.01 |
| 25–29 years old | Reference | Reference | ||
| 30–34 years old | 0.98 | 0.94, 1.01 | 1.02 | 0.99, 1.06 |
| 35–39 years old | 0.93 | 0.89, 0.97 | 1.00 | 0.96, 1.04 |
| 40–54 years old | 0.99 | 0.93, 1.06 | 1.08 | 1.01, 1.15 |
| Payer | ||||
| Medicare | 1.22 | 1.09, 1.35 | 1.14 | 1.02, 1.27 |
| Medicaid | 1.17 | 1.14, 1.20 | 1.11 | 1.08, 1.14 |
| Private insurance | Reference | Reference | ||
| Self-pay | 1.21 | 1.09, 1.34 | 1.15 | 1.04, 1.28 |
| No charge | 1.35 | 0.85, 2.16 | 1.21 | 0.76, 1.94 |
| Other | 1.01 | 0.93, 1.09 | 0.98 | 0.90, 1.06 |
| Median ZIP code income quartile | ||||
| Lowest income quartile | 1.21 | 1.17, 1.25 | 1.15 | 1.11, 1.20 |
| 2nd lowest quartile | 1.12 | 1.08, 1.17 | 1.08 | 1.04, 1.13 |
| 2nd highest quartile | 1.08 | 1.04, 1.12 | 1.06 | 1.02, 1.11 |
| Highest income quartile | Reference | Reference | ||
| Delivery postpartum hemorrhage | 1.46 | 1.38, 1.54 | 1.48 | 1.40, 1.56 |
| Cesarean delivery | 0.97 | 0.95, 0.99 | 0.99 | 0.96, 1.01 |
| Pregestational diabetes | 1.07 | 0.99, 1.15 | 1.14 | 1.06, 1.23 |
| Gestational diabetes | 1.01 | 0.97, 1.06 | 1.04 | 1.00, 1.09 |
| Systemic lupus erythematosus | 1.13 | 0.93, 1.36 | 1.13 | 0.93, 1.36 |
| Multiple gestation | 1.22 | 1.15, 1.29 | 1.30 | 1.22, 1.38 |
| Asthma | 0.99 | 0.94, 1.04 | 1.01 | 0.96, 1.07 |
| Chronic kidney disease | 1.43 | 1.25, 1.62 | 1.45 | 1.27, 1.65 |
| Hypertensive diseases of pregnancy | 0.85 | 0.83, 0.88 | 0.87 | 0.84, 0.89 |
| Chronic hypertension | 0.70 | 0.65, 0.75 | 0.68 | 0.64, 0.73 |
| Hospital bed size | ||||
| Small | Reference | Reference | ||
| Medium | 1.00 | 0.96, 1.05 | 1.03 | 0.98, 1.08 |
| Large | 0.97 | 0.93, 1.01 | 0.99 | 0.95, 1.03 |
| Hospital teaching status | ||||
| Metropolitan non-teaching | Reference | Reference | ||
| Metropolitan teaching | 0.89 | 0.87, 0.91 | 0.90 | 0.87, 0.92 |
| Non-metropolitan | 1.10 | 1.05, 1.14 | 1.07 | 1.02, 1.11 |
RR, risk ratio. 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. All variables in the table were included in the adjusted analysis.