Table 2.
Annual clinical and parasite responses to dihydroartemisinin-piperaquine treatment of uncomplicated Plasmodium falciparum malaria in Binh Phuoc province, Vietnam
| Characteristic | 2012 (n = 50) | 2013 (n = 66) | 2014 (n = 65) | 2015 (n = 72) | P value* |
|---|---|---|---|---|---|
| Fever clearance time [hours] | |||||
| Median (IQR) [hours] | 24 (18.30) | 18 (12.24) | 24 (18.36) | 24 (18.36) | <0.001 |
| Parasite clearance time (PCT100) | |||||
| Median (IQR) [hours] | 63 (48.84) | 60 (36.90) | 78 (36.168) | 78 (60.96) | 0.002 |
| Proportion with PCT > 72 h | 38% (19/50) | 41% (29/66) | 54% (35/65) | 57% (41/72) | |
| Parasite clearance half- life PC1/2 [hours] | |||||
| Median (IQR) | 3.75 (2.45;6.56) | 4.11 (2.10;6.27) | 5.80 (2.45;7.14) | 6.60 (4.65;8.03) | <0.001 |
| Geometric mean (95% CI) | 3.94 (3.38;4.60) | 3.67 (3.16;4.26) | 4.29 (3.66;5.03) | 5.52 (4.84;6.29) | |
| T1/2 > 5 h | 20/50 (40%) | 27/64 (42%) | 36/64 (56%) | 51/69 (74%) | |
| Treatment outcome (WHO) | |||||
| APCR# | 47/50 (94%) | 55/66 (83%) | 43/65 (66%) | 40/72 (56%) | |
| Early treatment failure | 0/50 (0%) | 0/66 (0%) | 1/65 (2%) | 0/72 (0%) | |
| Clinical treatment failure | 0/50 (0%) | 0/66 (0%) | 1/65 (2%) | 8/72 (11%) | |
| Parasitological treatment failure | 2/50 (4%) | 1/66 (2%) | 5/65 (8%) | 12/72 (17%) | – |
| Withdrawal | 1/50 (2%) | 4/66 (6%) | 2/65 (3%) | 3/72 (4%) | |
| Loss to follow-up | 0/50 (0%) | 6/66 (9%) | 13/65 (20%) | 9/72 (13%) | |
| Risk of failure [PCR—uncorrected] | |||||
| Uncorrected Kaplan–Meier estimate (ITT) | 4% | 2% | 12% | 30% | <0.001 |
| Uncorrected proportion (per protocol) | 2/49 (4%) | 1/56 (2%) | 7/50 (14%) | 20/60 (33%) | <0.001 |
| Risk of failure [PCR—corrected] | |||||
| Corrected Kaplan–Meier estimate (‘ITT’) | 0% | 0% | 5% | 22% | <0.001 |
| Corrected Proportion (‘per protocol’) | 0/47 (0%) | 0/55 (0%) | 3/46 (7%) | 14/54 (26%) | <0.001 |
| K13-propeller mutation | I543T:1/50 (2%) C580Y:5/50 (10%) P553L:6/50 (12%) Y493H:7/50 (14%) Total 19/50 (38%) |
I543T:3/65 (4.62%) C580Y:3/65 (3.08%) P553L:4/65 (6.15%) Y493H:14/65 (21.54%) 24/65 (37%) |
I543T:1/65 (1.54%) C580Y:25/65 (38.5%) P553L:2/65 (3.08%) Y493H:1/65 (1.54%) 29/65 (45%) |
C580Y:48/66 (72.73%) | <0.001 |
* P values are based on linear trend tests
APCR adequate clinical and parasitological responses