Table 5 Fitted mean of sample size and 95% confidence interval (CI), type III F statistic and the corresponding p value of the effect of class of prevalence on sample size adjusting for phase and interaction between prevalence and phase with adjustment for other covariates
Characteristics | Parallel 2-arm adjusting for other covariatesa | Single-group (1-arm) adjusting for other covariatesb | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
No. of trials, m | Fitted mean | 95% CI | F test | p value | No. of trials, m | Fitted mean | 95% CI | F test | p value | ||
Prevalence class | 6.32 | 0.0004 | 8.86 | <.0001 | |||||||
<1/1,000,000 | 5 | 45.19 | (20.92–97.64) | 12 | 21.15 | (7.95–56.26) | |||||
1–9/1,000,000 | 14 | 50.72 | (29.96–85.87) | 50 | 70.68 | (43.15–115.77) | |||||
1–9/100,000 | 154 | 112.53 | (77.92–162.52) | 276 | 84.64 | (55.38–129.36) | |||||
1–5/10,000 | 146 | 96.42 | (69.18–134.38) | 171 | 143.51 | (90.06–228.69) | |||||
Phase of investigation c | 8.59 | 0.0036 | 1.13 | 0.2873 | |||||||
Phase 2 | 167 | 51.75 | (33.71–79.44) | 455 | 56.97 | (37.66–86.17) | |||||
Phase 3 | 152 | 96.36 | (61.60–150.74) | 54 | 74.80 | (40.53–138.05) | |||||
Prevalence x Phase | 1.05 | 0.3727 | 5.32 | 0.0013 | |||||||
Phase 2 | <1/1,000,000 | 3 | 31.71 | (12.42–80.93) | 11 | 29.10 | (15.32–55.27) | ||||
1–9/1,000,000 | 8 | 48.03 | (25.40–90.80) | 39 | 62.95 | (39.30–100.84) | |||||
1–9/100,000 | 85 | 72.78 | (49.53–106.94) | 244 | 76.86 | (50.96–115.92) | |||||
1–5/10,000 | 71 | 64.72 | (45.54–91.98) | 161 | 74.79 | (49.48–113.06) | |||||
Phase 3 | <1/1,000,000 | 2 | 64.41 | (20.93–198.25) | 1 | 15.37 | (2.61–90.47) | ||||
1–9/1,000,000 | 6 | 53.57 | (26.74–107.31) | 11 | 79.36 | (40.81–154.35) | |||||
1–9/100,000 | 69 | 174.00 | (117.36–257.98) | 32 | 93.21 | (56.91–152.67) | |||||
1–5/10,000 | 75 | 143.65 | (100.29–205.75) | 10 | 275.36 | (147.46–514.19) | |||||