Table 2.
Primary Efficacy Outcomes in the India and Tanzania Trials.*
| Outcome | India Trial | Tanzania Trial | ||||||
|---|---|---|---|---|---|---|---|---|
| 500 mg Calcium | 1500 mg Calcium | Relative Risk (95% CI) | P Value for Noninferiority | 500 mg Calcium | 1500 mg Calcium | Relative Risk (95% CI) | P Value for Noninferiority | |
| Preeclampsia | ||||||||
| Primary intention-to-treat analysis | 164/5497 (3.0) | 196/5503 (3.6) | 0.84 (0.68–1.03) | <0.001 | 165/5503 (3.0) | 150/5497 (2.7) | 1.10 (0.88–1.36) | <0.001 |
| Per-protocol analysis† | 156/5027 (3.1) | 184/5022 (3.7) | 0.85 (0.69–1.05) | 148/4420 (3.3) | 128/4448 (2.9) | 1.16 (0.92–1.46) | ||
| Sensitivity analysis excluding participants who had pregnancy loss or withdrew before 20 wk of gestation | 164/5397 (3.0) | 196/5408 (3.6) | 0.84 (0.69–1.03) | 165/5361 (3.1) | 150/5297 (2.8) | 1.09 (0.87–1.35) | ||
| Preterm birth ‡ | ||||||||
| Primary intention-to-treat analysis | 593/5195 (11.4) | 665/5193 (12.8) | 0.89 (0.80–0.98) | <0.001 | 531/5109 (10.4) | 493/5081 (9.7) | 1.07 (0.95–1.21) | 0.10 |
| Per-protocol analysis§ | 552/4852 (11.4) | 629/4842 (13.0) | 0.87 (0.78–0.97) | 448/4279 (10.5) | 430/4323 (9.9) | 1.06 (0.93–1.20) | ||
| Sensitivity analysis involving single-ton live births | 559/5116 (10.9) | 637/5149 (12.4) | 0.88 (0.79–0.98) | 448/4964 (9.0) | 412/4905 (8.4) | 1.07 (0.95–1.22) | ||
P values are for noninferiority. A post hoc Bonferroni correction was applied to the primary efficacy outcomes within each trial to account for tests of the two efficacy outcomes; two-sided 95% confidence intervals are shown, and a P value for noninferiority of less than 0.025 was considered to indicate statistical significance.
The per-protocol analysis for preeclampsia included all the pregnant participants who had more than 75% adherence to the randomly assigned regimen, had a pregnancy of at least 20 weeks’ gestation, and had a delivery outcome assessed (excluding withdrawal and loss to follow-up in pregnancy).
Gestational age was determined on the basis of the best obstetrical estimate.
The per-protocol analysis for preterm birth included live births born to pregnant participants who had more than 75% adherence to the randomly assigned regimen.