Table 2.
Adjusted and unadjusted models for antibiotic administration during vaginal delivery hospitalizations without an indication for antibiotics
| Unadjusted model risk ratio (95% CI) | Adjusted model adjusted risk ratio (95% CI) | |
|---|---|---|
| Year | ||
| 2006 | Referent | Referent |
| 2007 | 0.96 (0.95, 0.97)** | 0.96 (0.95, 0.97)** |
| 2008 | 0.92 (0.91, 0.92)** | 0.92 (0.91, 0.93)** |
| 2009 | 0.87 (0.86, 0.87)** | 0.87 (0.86, 0.88)** |
| 2010 | 0.83 (0.83, 0.84)** | 0.83 (0.82, 0.84)** |
| 2011 | 0.78 (0.77, 0.79)** | 0.79 (0.78, 0.79)** |
| 2012 | 0.74 (0.74, 0.75)** | 0.75 (0.75, 0.76)** |
| 2013 | 0.68 (0.68, 0.69)** | 0.68 (0.68, 0.69)** |
| 2014 | 0.60 (0.60, 0.61)** | 0.60 (0.59, 0.60)** |
| 2015 1st quarter | 0.56 (0.55, 0.57)** | 0.56 (0.55, 0.57)** |
| Age in years | ||
| 18-24 | Referent | Referent |
| 25-34 | 0.88 (0.87, 0.88)** | 0.96 (0.96, 0.97)** |
| 35-39 | 0.89 (0.88, 0.90)** | 1.00 (0.99, 1.01) |
| ≥ 40 | 0.91 (0.89, 0.92)** | 1.02 (1.00, 1.03)* |
| Marital Status | ||
| Married | Referent | Referent |
| Single | 1.16 (1.15, 1.16)** | 1.06 (1.06, 1.07)** |
| Other/Unknown | 1.34 (1.33, 1.35)** | 1.23 (1.22, 1.23)** |
| Race | ||
| White | Referent | Referent |
| Black | 1.44 (1.43, 1.45)** | 1.26 (1.25, 1.27)** |
| Other | 1.12 (1.11, 1.12)** | 1.07 (1.06, 1.07)** |
| Unknown | 0.63 (0.56, 0.71)** | 0.80 (0.71, 0.90)* |
| Payer | ||
| Medicare | 1.25 (1.22, 1.28)** | 1.27 (1.24, 1.30)** |
| Medicaid | 1.17 (1.17, 1.18)** | 1.09 (1.08, 1.09)** |
| Commercial | Referent | Referent |
| Uninsured | 1.22 (1.20, 1.23)** | 1.09 (1.08, 1.10)** |
| Unknown | 1.06 (1.04, 1.07)** | 1.01 (0.99, 1.02) |
| Rurality | ||
| Urban | 1.38 (1.37, 1.40)** | 1.36 (1.35, 1.38)** |
| Rural | Referent | Referent |
| Hospital Teaching | ||
| No | Referent | Referent |
| Yes | 1.01 (1.00, 1.01)* | 0.97 (0.97, 0.98)** |
| Hospital Bed Size | ||
| <400 | Referent | Referent |
| 400-600 | 1.02 (1.01, 1.02)** | 0.99 (0.99, 1.00)* |
| >600 | 1.25 (1.24, 1.25)** | 1.14 (1.13, 1.14)** |
| Region of Hospital | ||
| Northeastern | Referent | Referent |
| Midwest | 1.13 (1.12, 1.14)** | 1.18 (1.17, 1.19)** |
| South | 1.42 (1.41, 1.43)** | 1.42 (1.41, 1.43)** |
| West | 0.98 (0.98, 0.99)** | 1.01 (1.00, 1.02)* |
| Postpartum hemorrhage | 1.33 (1.31, 1.35)** | 1.33 (1.31, 1.34)** |
| Preeclampsia | 1.31 (1.30, 1.33)** | 1.26 (1.24, 1.27)** |
| Gestational diabetes | 1.00 (0.99, 1.01) | 1.03 (1.02, 1.04)** |
| Pregestational diabetes | 1.26 (1.23, 1.30)** | 1.21 (1.18, 1.25)** |
| Multiple gestation | 1.50 (1.46, 1.53)** | 1.47 (1.44, 1.51)** |
Adjusted model includes all of the factors in the table as well as adjustment for hospital-level clustering. CI, confidence interval.
*
p<0.05
**
p<0.01.
Evidence-based diagnoses for administration of antibiotics includes preterm premature rupture of membranes, endometritis, chorioamnionitis, GBS colonization, and other infectious complications. Given the large sample and multiple comparisons, interpretation of results at p<0.01 may be more appropriate.