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Table 4 Power to detect a difference between RT and nRT groups in Randomisation B

From: Protocol, rationale and design of SELPHI: a randomised controlled trial assessing whether offering free HIV self-testing kits via the internet increases the rate of HIV diagnosis

HIV Incidence (per 100 PY) Median time to diagnosis (years) in nRT group Power (%) Estimated HIV infections per group Median number HIV diagnoses (nRT/RT) Median hazard ratio (RT versus nRT)
1.5 1.0 56 53 24/40 1.73
1.5 72 53 21/40 1.91
2.0 82 53 19/40 2.08
2.5 87 53 18/40 2.21
2.0 1.0 75 71 30/53 1.70
1.5 83 71 28/52 1.94
2.0 91 71 26/52 2.08
2.5 93 71 24/51 2.20
2.5 1.0 83 89 38/66 1.73
1.5 93 89 34/65 1.92
2.0 96 89 32/65 2.09
2.5 98 89 30/64 2.25
3.0 1.0 89 107 46/78 1.74
1.5 96 107 41/77 1.92
2.0 98 107 38/77 2.09
2.5 99 107 36/77 2.23
  1. Power to detect a difference at 2α = 0.05 by log-rank test