Table 1.
Statistical power for a trial sample size of 2300 with 1:1 randomization to vitamin D3 and placebo arms, and a nominal Type I error rate (alpha) of 0.05
| Hazard ratio (HR) for maternal HIV progression (any increase in WHO HIV stage) or death | |||
| Cumulative incidence over average 17 months follow-upa | HR = 0.60 | HR = 0.65 | HR = 0.70 |
| 12.5% | 95.7% | 88.3% | 75.5% |
| 15% | 98.0% | 93.0% | 82.3% |
| 17.5% | 99.1% | 95.8% | 87.3% |
| Relative risk (RR) of small-for gestational age (SGA) birth | |||
| Cumulative incidence of SGA in placebo arm | RR = 0.65 | RR = 0.70 | RR = 0.75 |
| 10% | 98.4% | 93.4% | 81.2% |
| 12% | 99.5% | 96.9% | 88.3% |
| 14% | 99.9% | 98.7% | 93.0% |
| Relative risk (RR) of child stunting at 12 months of age (LAZ < –2) | |||
| Cumulative incidence of stunting in placebo arm | RR = 0.60 | RR = 0.70 | RR = 0.80 |
| 15% | >99.9% | 98.8% | 78.4% |
| 20% | >99.9% | >99.9% | 90.3% |
| 25% | >99.9% | >99.9% | 96.3% |
aAssumes the monthly incidence of maternal human immunodeficiency virus (HIV) progression or death is constant during follow-up
LAZ length-for-age z-score, WHO World Health Organization