ehealth digital library

Digital library of
the Tanzania
health
community

Baseline Data of Parasite Clearance in Patients with Falciparum Malaria Treated with an Artemisinin Derivative: an Individual Patient Data Meta-Analysis.

WWARN Parasite Clearance Study Group, W. (2015) Baseline Data of Parasite Clearance in Patients with Falciparum Malaria Treated with an Artemisinin Derivative: an Individual Patient Data Meta-Analysis. Malaria journal, 14 (1). p. 359. ISSN 1475-2875

[img]
Preview
PDF
WWARN_Parasite_Clearance_Study_Group.pdf - Published Version
Available under License Creative Commons Attribution Non-commercial.

Download (1MB)

Abstract

Artemisinin resistance in Plasmodium falciparum manifests as slow parasite clearance but this measure is also influenced by host immunity, initial parasite biomass and partner drug efficacy. This study collated data from clinical trials of artemisinin derivatives in falciparum malaria with frequent parasite counts to provide reference parasite clearance estimates stratified by location, treatment and time, to examine host factors affecting parasite clearance, and to assess the relationships between parasite clearance and risk of recrudescence during follow-up. Data from 24 studies, conducted from 1996 to 2013, with frequent parasite counts were pooled. Parasite clearance half-life (PC1/2) was estimated using the WWARN Parasite Clearance Estimator. Random effects regression models accounting for study and site heterogeneity were used to explore factors affecting PC1/2 and risk of recrudescence within areas with reported delayed parasite clearance (western Cambodia, western Thailand after 2000, southern Vietnam, southern Myanmar) and in all other areas where parasite populations are artemisinin sensitive. PC1/2 was estimated in 6975 patients, 3288 of whom also had treatment outcomes evaluate d during 28-63 days follow-up, with 93 (2.8 %) PCR-confirmed recrudescences. In areas with artemisinin-sensitive parasites, the median PC1/2 following three-day artesunate treatment (4 mg/kg/day) ranged from 1.8 to 3.0 h and the proportion of patients with PC1/2 >5 h from 0 to 10 %. Artesunate doses of 4 mg/kg/day decreased PC1/2 by 8.1 % (95 % CI 3.2-12.6) compared to 2 mg/kg/day, except in populations with delayed parasite clearance. PC1/2 was longer in children and in patients with fever or anaemia at enrolment. Long PC1/2 (HR = 2.91, 95 % CI 1.95-4.34 for twofold increase, p < 0.001) and high initial parasitaemia (HR = 2.23, 95 % CI 1.44-3.45 for tenfold increase, p < 0.001) were associated independently with an increased risk of recrudescence. In western Cambodia, the region with the highest prevalence of artemisinin resistance, there was no evidence for increasing PC1/2 since 2007. Several factors affect PC1/2. As substantial heterogeneity in parasite clearance exists between locations, early detection of artemisinin resistance requires reference PC1/2 data. Studies with frequent parasite count measurements to characterize PC1/2 should be encouraged. In western Cambodia, where PC1/2 values are longest, there is no evidence for recent emergence of higher levels of artemisinin resistance.

Item Type: Article
Keywords: Malaria, Parasite clearance, Artemisinin resistance, Drug resistance, Plasmodium falciparum
Subjects: Malaria > Surveillance, monitoring, evaluation
Malaria > Diagnosis & treatment
Divisions: Other
Depositing User: Mr Joseph Madata
Date Deposited: 07 Jan 2016 09:14
Last Modified: 07 Jan 2016 09:14
URI: http://ihi.eprints.org/id/eprint/3392

Actions (login required)

Edit Item Edit Item

Downloads

Downloads per month over past year

View more statistics