TABLE 2.

Day 42 cumulative risk of failure following DHP in 198 patients with available plasma piperaquine concentrations on day 7

Parasitological failureDay 7 piperaquine concn < 30 ng/mlDay 7 piperaquine concn ≥ 30 ng/mlHRa (95% CI); P
nRisk (%) (95% CI)nRisk (%) (95% CI)
Any species after initial infection with any species5236 (20-52)1446.8 (1.9-12)6.1 (2.4-15); 0.001
P. falciparum
    After initial infection with any species5223 (9.6-37)1443.8 (0.1-7.5)6.6 (1.9-23); 0.003
    True recrudescence of P. falciparumb446.1 (0-14.5)10600.02c
    After reinfection with P. falciparum5218 (4.7-31)1443.8 (0.1-7.5)4.9 (1.3-18); 0.017
P. vivax
    After initial infection with any species5226 (10-42)1443.1 (0-6.6)9.0 (2.3-35); 0.001
    After initial infection with P. vivax (alone or mixed)2350 (21-79)604.8 (0-11)11.6 (2.3-57); 0.003
  • a The HR was calculated using a Cox regression model after stratifying for the initial species of infection.

  • b After correcting by PCR genotyping, in patients initially infected with P. falciparum (alone or mixed).

  • c Value for P.