Table 2.
Stratified analysis and meta-regression of the incidence rate of HIV during pregnancy and breastfeeding
| Stratum Specific Estimates | Univariate Meta-Regression | Multivariate Meta-Regression* | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Variable | Number of Estimates | Pooled incidence rate | (95% PI) | Ratio of the pooled incidence rate | (95% CI) | P-value | Omnibus p-value | Ratio of the pooled incidence rate | (95% CI) | P-value | Omnibus p-value |
| Region | |||||||||||
| Southern Africa | 18 | 4.2 | (1.4, 12.3) | 1.0 | - | - | - | 1.0 | - | - | - |
| Eastern Africa | 10 | 3.3 | (1.1, 9.9) | 0.8 | (0.5, 1.2) | 0.3 | - | 0.7 | (0.4, 1.1) | 0.1 | - |
| Southeastern Africa | 3 | 2.4 | (0.7, 8.1) | 0.6 | (0.3, 1.1) | 0.1 | - | 0.9 | (0.3, 2.3) | 0.8 | - |
| Western Africa | 3 | 2.9 | (0.7, 11.5) | 0.7 | (0.3, 1.8) | 0.4 | 0.3 | 0.7 | (0.3, 1.8) | 0.4 | 0.4 |
| Calendar time† | |||||||||||
| Pre-2010 | 23 | 4.1 | (1.4, 12.2) | 1.0 | - | - | - | 1.0 | - | - | - |
| 2010–2014 | 8 | 2.9 | (0.9, 8.8) | 0.7 | (0.4, 1.2) | 0.2 | - | 0.7 | (0.4, 1.2) | 0.2 | - |
| Post-2014 | 4 | 2.1 | (0.7, 6.5) | 0.5 | (0.3, 0.9) | 0.02 | 0.04 | 0.4 | (0.2, 0.7) | 0.002 | 0.007 |
| High risk cohort | |||||||||||
| No | 32 | 3.6 | (1.2, 11.3) | 1.0 | - | - | - | 1.0 | - | - | - |
| Yes | 4 | 4.3 | (1.2, 15.9) | 1.2 | (0.5, 1.8) | 0.8 | 0.8 | 1.2 | (0.6, 2.5) | 0.3 | 0.3 |
| Participants enrolled in an HIV-prevention clinical trial | |||||||||||
| No | 29 | 3.5 | (1.2, 10.5) | 1.0 | - | - | - | 1.0 | - | - | - |
| Yes | 5 | 4.3 | (1.3, 14.2) | 1.2 | (0.6–2.4) | 0.6 | 0.6 | 1.9 | (0.9–4.1) | 0.2 | 0.2 |
| Age group | |||||||||||
| < 20 years | 7 | 3.8 | (1.5, 10.1) | 1.0 | - | - | - | 1.0 | - | - | - |
| 20–24 years | 6 | 2.8 | (1.1, 7.4) | 0.7 | (0.6, 1.0) | 0.05 | - | 0.7 | (0.5, 1.0) | 0.05 | - |
| 25–29 years | 5 | 2.5 | (0.9, 6.6) | 0.6 | (0.5, 0.9) | 0.01 | - | 0.6 | (0.4, 0.9) | 0.01 | - |
| 30+ years | 6 | 1.8 | (0.7, 4.8) | 0.5 | (0.3, 0.7) | <0.001 | <0.001 | 0.5 | (0.3, 0.7) | <0.001 | <0.001 |
| Undefined | 16 | - | - | - | - | - | - | - | - | - | - |
| Study Design | |||||||||||
| Prospective cohort | 21 | 3.4 | (1.2, 9.4) | 1.0 | - | - | - | 1.0 | - | - | - |
| Cross-sectional retesting | 11 | 4.7 | (1.6, 13.5) | 1.4 | (0.9, 2.1) | 0.1 | - | 1.8 | (1.0, 3.4) | 0.06 | - |
| Surveillance study | 2 | 2.2 | (0.6, 7.4) | 0.6 | (0.3, 1.4) | 0.2 | 0.1 | 0.9 | (0.3, 2.8) | 0.8 | 0.1 |
| Use of results from repeat HIV testing to identify HIV seroconversions | |||||||||||
| Yes | 30 | 3.7 | (1.3, 11.1) | 1.0 | - | - | - | 1.0 | - | - | - |
| No | 4 | 2.8 | (0.8, 9.4) | 0.8 | (0.4, 1.4) | 0.4 | 0.4 | 0.6 | (0.2, 1.6) | 0.3 | 0.3 |
| Reproductive periods observed during study follow-up | |||||||||||
| Pregnancy only | 11 | 4.3 | (1.4, 13.0) | 1.0 | - | - | - | 1.0 | - | - | - |
| Breastfeeding only | 5 | 3.8 | (1.2, 11.9) | 0.9 | (0.5, 1.6) | 0.7 | - | 0.9 | (0.4, 1.7) | 0.6 | - |
| Pregnancy and Breastfeeding | 10 | 3.8 | (1.2, 11.6) | 0.9 | (0.5, 1.5) | 0.7 | - | 0.7 | (0.4, 1.3) | 0.2 | - |
| Pregnancy, Breastfeeding, Non-Pregnant/Non-Breastfeeding | 8 | 2.7 | (0.9, 8.3) | 0.6 | (0.4, 1.1) | 0.1 | 0.4 | 0.6 | (0.3, 1.3) | 0.2 | 0.6 |
| Estimated timing of HIV seroconversion | |||||||||||
| Date between last negative and first positive HIV test | 11 | 2.6 | (0.9, 7.3) | 1.0 | - | - | - | 1.0 | - | - | - |
| Date of the first positive HIV test | 4 | 5.3 | (1.8, 16.1) | 2.0 | (1.1, 3.7) | 0.02 | 0.02 | 4.3 | (1.4, 13.2) | 0.01 | 0.01 |
| Undefined | 19 | - | - | - | - | - | - | - | - | - | - |
| HIV RNA/DNA PCR used in HIV testing algorithm | |||||||||||
| No | 21 | 4.2 | (1.5, 12.0) | 1.0 | - | - | - | 1.0 | - | - | - |
| Yes | 5 | 3.1 | (1.0, 9.5) | 0.7 | (0.4, 1.3) | 0.3 | 0.3 | 0.9 | (0.4, 2.1) | 0.8 | 0.8 |
| Undefined | 8 | - | - | - | - | - | - | - | - | - | - |
Acronyms: CI=confidence interval; HR=hazard ratio; PI=prediction interval
*
Unless otherwise indicated, models were adjusted for region, length of study implementation, and calendar time.
†
Multivariate meta-regression adjusted for region and length of study implementation only.