Table 2.
Risk ratios and risk differences of the association of pregnancy loss with most recent cross-sectional viral load measure before the pregnancy ended (N = 454), log10 copy-years viremia from ART initiation to conception (N = 250), and log10 copy-years viremia in the two years prior to conception (N = 376).
| Pregnancy loss | Relative effect measures | Absolute effect measures | |||
|---|---|---|---|---|---|
| Losses/N | RR (95% CI) | aRR (95% CI)∗ | RD (95% CI) | aRD (95% CI)∗ | |
| Analysis 1: most recent log10 viral load measure | |||||
| Continuous exposure | 158/454 | 1.27 (1.13, 1.42) | 1.17 (1.01, 1.35) | 0.10 (0.06, 0.14) | 0.04 (−0.01, 0.08) |
| Dichotomous exposure | |||||
| ≤1.60 | 41/181 | 1. | 1. | 0. | 0. |
| >1.60 | 117/273 | 1.89 (1.39, 2.58) | 1.23 (0.87, 1.74) | 0.20 (0.11, 0.29) | 0.05 (−0.04, 0.14)† |
| Categorical‡ | |||||
| Q1: ≤1.60 | 41/181 | 1. | 1. | 0. | 0. |
| Q2: 1.61–3.00 | 30/91 | 1.47 (0.98, 2.19) | 1.15 (0.79, 1.68) | 0.10 (−0.01, 0.21) | 0.03 (−0.06, 0.12) † |
| Q3: 3.01–4.00 | 39/90 | 1.87 (1.27, 2.75) | 1.20 (0.77, 1.87) | 0.19 (0.07, 0.32) | 0.04 (−0.09, 0.17) † |
| Q4: >4.00 | 48/92 | 2.36 (1.68, 3.31) | 1.59 (0.99, 2.56) | 0.30 (0.18, 0.42) | 0.14 (−0.01, 0.28) † |
|
| |||||
| Analysis 2: log10 copy-years viremia since ART initiation | |||||
| Continuous exposure | 92/250 | 0.83 (0.73, 0.95) | 0.80 (0.69, 0.92) | −0.07 (−0.13, −0.02) | −0.10 (−0.14, −0.05) |
| Quartile of exposure‡ | |||||
| Q1: 0–3.78 | 29/62 | 1. | 1. | 0. | 0. |
| Q2: 3.79–4.38 | 24/63 | 0.84 (0.55, 1.30) | 0.85 (0.56, 1.30) | −0.07 (−0.25, −0.11) | −0.05 (−0.21, 0.12) |
| Q3: 4.39–4.94 | 22/63 | 0.72 (0.45, 1.14) | 0.70 (0.44, 1.13) | −0.13 (−0.31, −0.05) | −0.15 (−0.32, 0.03) |
| Q4: >4.94 | 17/62 | 0.61 (0.37, 1.00) | 0.60 (0.36, 0.99) | −0.18 (−0.35, −0.01) | −0.18 (−0.36, −0.01) |
|
| |||||
| Analysis 3: log10 copy-years viremia in two years before pregnancy | |||||
| Continuous exposure | 149/376 | 1.12 (1.01, 1.24) | 1.00 (0.90, 1.11) | 0.05 (0.01, 0.09) | −0.01 (−0.05, 0.03) |
| Quartile of exposure‡ | |||||
| Q1: 0–4.26 | 28/94 | 1. | 1. | 0. | NC |
| Q2: 4.27–5.73 | 34/94 | 1.19 (0.78, 1.81) | 0.90 (0.61, 1.32) | 0.06 (−0.08, 0.20) | NC |
| Q3: 5.74–6.49 | 46/94 | 1.57 (1.07, 2.29) | 1.07 (0.72, 1.57) | 0.17 (0.03, 0.31) | NC |
| Q4: >6.49 | 41/94 | 1.43 (0.97, 2.09) | 0.92 (0.63, 1.35) | 0.13 (−0.01, 0.26) | NC |
ART = antiretroviral therapy, RR = risk ratio, aRR = adjusted risk ratio, RD = risk difference, and aRD = adjusted risk difference. NC = nonconvergence of model.
∗Adjusted for maternal age (with a linear spline at age 35), race, income, noninjection drug use, prior pregnancy loss, smoking, CD4 count, and ART use (separately controlling for mono-/dual and HAART versus none) prior to viral load measurement (for analyses 1 and 3).
†Point estimates controlled for any ART instead of separately controlling for mono-/dual and HAART due to model nonconvergence.
‡Categories of cross-sectional viral load measures (analysis 1) were based on clinically informative cut-points, while the categories for cumulative viremia measures (analysis 2) were based on statistical quartiles.