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Table 1 Illustrating how the "Intention to treat" approach ascribing indeterminate treatment outcomes as failures overestimates the true failure rate. High failure rate:

From: Some considerations in the design and interpretation of antimalarial drug trials in uncomplicated falciparum malaria

Follow-up

A (%)

R = F(%)

FITT (%)

Overestimation of failure rate (%)

6 weeks

6

15

15.3

2%

8 weeks

20

25

26

4%

10 weeks

45

25

27.25

9%

12 weeks

68

25

28.4

14%

20 weeks

75

25

28.75

15%

  1. Assume that the entomological inoculation rate is 1/month (Figure 4), the true failure rate (F) is 25%, and 5% of PCR pairs are indeterminate. The patients are censored when a recurrent infection occurs.
  2. Then at 4 weeks follow-up in the trial, the recurrence rate = 3.5% (2.5% true recrudescence, 1% true recurrence)
  3. True failure rate = 2.5%, ITT analysis failure rate = 2.55%, overestimation 1.275%. FITT (%) = A + 0.05 R
  4. A – cumulative probability of developing a patent new infection
  5. R – cumulative probability of developing a patent recrudescence
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Malaria Journal

ISSN: 1475-2875

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