Medical informatics in medical research - the Severe Malaria in African Children (SMAC) Network's experience.

OBJECTIVES: Computers are widely used for data management in clinical trials in the developed countries, unlike in developing countries. Dependable systems are vital for data management, and medical decision making in clinical research. Monitoring and evaluation of data management is critical. In this paper we describe database structures and procedures of systems used to implement, coordinate, and sustain data management in Africa. We outline major lessons, challenges and successes achieved, and recommendations to improve medical informatics application in biomedical research in sub-Saharan Africa. METHODS: A consortium of experienced research units at five sites in Africa in studying children with disease formed a new clinical trials network, Severe Malaria in African Children. In December 2000, the network introduced an observational study involving these hospital-based sites. After prototyping, relational database management systems were implemented for data entry and verification, data submission and quality assurance monitoring. RESULTS: Between 2000 and 2005, 25,858 patients were enrolled. Failure to meet data submission deadline and data entry errors correlated positively (correlation coefficient, r = 0.82), with more errors occurring when data was submitted late. Data submission lateness correlated inversely with hospital admissions (r = -0.62). CONCLUSIONS: Developing and sustaining dependable DBMS, ongoing modifications to optimize data management is crucial for clinical studies. Monitoring and communication systems are vital in multi-center networks for good data management. Data timeliness is associated with data quality and hospital admissions.

[Treatment of pediatric malaria in Africa: act at issue]. / Traitement du paludisme de l'enfant en Afrique: les act en question.

Artemisinin-based combination therapies (ACT) have been proposed as alternatives to currently used antimalarials and are poised large-scale deployment in Africa. These combinations are particularly attractive for managing malaria in children. Expected benefits of ACT include enhanced efficacy, rapid action, stabilized antimalarial resistance growth and lower malaria transmission. This article discusses what can be reasonably expected of ACT in an African setting with emphasis on patient comfort.

Traitement du paludisme de l'enfant en Afrique : les ACT en question

Les Artemisinin-based Combination Therapies (ACT) representent la majorite des alternatives aux antipaludiques de reference et sont sur le point d'etre deployees largement en Afrique. Elles sont particulierement attractives pour traiter les enfants. Les vertus annoncees de ces associations sont multiples : puissance accrue; rapidite d'action; stabilisation de la chimioresistance et reduction de la transmission. L'abondante litterature consacree aux ACT depuis quelques annees permet de faire le point sur ces divers aspects; en insistant sur la question du confort des enfants malades

Comparison of chlorproguanil-dapsone with sulfadoxine-pyrimethamine for the treatment of uncomplicated falciparum malaria in young African children: double-blind randomised controlled trial.

BACKGROUND: Increasing resistance to sulfadoxine-pyrimethamine is leading to a decline in its effectiveness. We aimed to assess the safety profile of chlorproguanil-dapsone (CD), and to compare the safety and efficacy of this drug with that of sulfadoxine-pyrimethamine (SP) as treatment for uncomplicated falciparum malaria. METHODS: We undertook a double-blind, randomised trial in 1850 consecutively recruited children with uncomplicated falciparum malaria, pooling data from five African countries. Analyses were based on all randomised patients with available data. FINDINGS: CD was significantly more efficacious than SP (odds ratio 3.1 [95% CI 2.0-4.8]); 1313 patients (96%) given CD and 306 (89%) given SP achieved acceptable clinical and parasitological response by day 14. Adverse events were reported in 46% and 50% of patients randomised to CD and SP, respectively (treatment difference -4.4%, [95% CI -10.1 to 1.3]). Haemoglobin in the CD group was significantly lower than in the SP group at day 7, a difference of -4 g/L (95% CI -6 to -2). Mean day 14 haemoglobin (measured only for the small number of patients whose day 7 data caused concern) was 94 g/L (92-96) and 97 g/L (92-102) after CD and SP, respectively. Glucose-6-phosphate dehydrogenase deficient patients on CD had greater odds than those on SP of having a fall of 20 g/dL or more in haemoglobin when baseline temperature was high. Methaemoglobinaemia was seen in the CD group (n=320, mean 0.4% [95% CI 0.4-0.4]) before treatment, 4.2% (95% CI 3.8-4.6) (n=301) at day 3, and 0.6% (0.6-0.7) (n=300) at day 7). INTERPRETATION: CD had greater efficacy than SP in Africa and was well tolerated. Haematological adverse effects were more common with CD than with SP and were reversible. CD is a useful alternative where SP is failing due to resistance.

Amodiaquine-artesunate versus amodiaquine for uncomplicated Plasmodium falciparum malaria in African children: a randomised, multicentre trial.

BACKGROUND: Increasing drug resistance limits the choice of efficacious chemotherapy against Plasmodium falciparum malaria in Africa. Amodiaquine still retains efficacy against P falciparum in many African countries. We assessed the safety, treatment efficacy, and effect on gametocyte carriage of adding artesunate to amodiaquine in three randomised trials in Kenya, Sénégal, and Gabon. METHODS: We enrolled 941 children (400 in Kenya, 321 in Sénégal, and 220 in Gabon) who were 10 years or older and who had uncomplicated P falciparum malaria. Patients were randomly assigned amodiaquine (10 mg/kg per day for 3 days) plus artesunate (4 mg/kg per day for 3 days) or amodiaquine (as above) and placebo (for 3 days). The primary endpoints were parasitological cure rates at days 14 and 28. Analysis was by intention to treat and by an evaluability method. FINDINGS: Both regimens were well tolerated. Six patients in the amodiaquine-artesunate group and five in the amodiaquine group developed early, drug-induced vomiting, necessitating alternative treatment. By intention-to-treat analysis, the day-14 cure rates for amodiaquine-artesunate versus amodiaquine were: 175/192 (91%) versus 140/188 (74%) in Kenya (D=16.7% [95% CI 9.3-24.1], p<0.0001), 148/160 (93%) versus 147/157 (94%) in Sénégal (-1.1% [-6.7 to 4.5], p=0.7), and 92/94 (98%) versus 86/96 (90%) in Gabon (8.3% [1.5-15.1], p=0.02). The corresponding rates for day 28 were: 123/180 (68%) versus 75/183 (41%) in Kenya (27.3% [17.5-37.2], p<0.0001), 130/159 (82%) versus 123/156 (79%) in Sénégal (2.9% [-5.9 to 11.7], p=0.5), and 80/94 (85%) versus 70/98 (71%) in Gabon (13.7% [2.2-25.2], p=0.02). Similar rates were obtained by evaluability analysis. INTERPRETATION: The combination of artesunate and amodiaquine improved treatment efficacy in Gabon and Kenya, and was equivalent in Sénégal. Amodiaquine-artesunate is a potential combination for use in Africa. Further investigations to assess the potential effect on the evolution of drug resistance, disease transmission, and safety of amodiaquine-artesunate are warranted.

Reassessment of the resistance of Plasmodium falciparum to chloroquine in Gabon: implications for the validity of tests in vitro vs. in vivo.

Increasing resistance of Plasmodium falciparum to antimalarial drugs presents a major risk factor for people living in endemic areas of tropical Africa. In Lambaréné, Gabon, regular surveillance of chloroquine sensitivity of P. falciparum in vitro has been carried out since 1992 using the WHO standard microtest. Results indicated that from 1994 onwards chloroquine resistance in vitro decreased significantly and that by 2000, about 70% of parasite isolates seemed to be sensitive to chloroquine in vitro. In 2001, we conducted a clinical study to reassess the efficacy of chloroquine in vivo for the treatment of uncomplicated P. falciparum malaria. Twenty-six patients aged 4-15 years were included in this study. Most unexpectedly, the study demonstrated high-grade resistance to chloroquine in vivo (failure rate on day 28 of 100%). As a consequence, tests of parasite susceptibility to chloroquine in vitro were repeated using the same protocol except for the replacement of previously used commercially available predosed WHO culture plates by independently dosed plates. All tested P. falciparum isolates were highly resistant to chloroquine, correlating well with our clinical findings. We concluded that high level resistance of P. falciparum to chloroquine persists in the study area. Neglect or absence of quality controls of essential test material can lead to invalid study results and wrong conclusions and should always be suspected in the case of major fluctuations in the sensitivity patterns of an antimalarial drug in vitro. In addition, our results highlight the supreme value of tests in vivo in providing reliable estimates of the efficacy of an antimalarial in a specific area.

Change in Plasmodium falciparum genotype during successive malaria episodes in Gabonese children.

Extensive polymorphism in the malaria parasite Plasmodium falciparum is one of the major obstacles to controlling the disease. With the aim of analysing the dynamics of P. falciparum inoculations, we investigated the parasite genotypes of successive malaria episodes. Polymerase chain reaction was performed on blood samples collected longitudinally from 31 children in Lambaréné, Gabon. The polymorphic regions of the merozoite surface antigens 1 and 2 were used as genetic markers. The data show that children in this area are exposed to many different P. falciparum strains. In a few cases, the same parasite genotypic pattern was observed in samples from two consecutive clinical attacks indicating probable recrudescences after therapy. In six cases the first successive infections with a particular merozoite surface antigen (MSA)-2 strain (3D7) were followed by infections with the other MSA-2 genotype (FC27). In all other cases the genetic characteristics of the parasite were different from one infection to the next, indicating that reinfection was caused by a new parasite strain.

Malaria chemoprophylaxis with tafenoquine: a randomised study.

BACKGROUND: Tafenoquine is an analogue of primaquine with an improved therapeutic and safety profile. It has a long half-life and activity against liver-stage malaria parasites, so may be useful for chemoprophylaxis. In this randomised, double-blind study we assessed the efficacy and safety of tafenoquine in different doses. METHODS: 2144 individuals aged 12-20 years living in Lambaréné, Gabon, an endemic area for Plasmodium falciparum malaria, were invited to take part. 535 attended, and 426 eligible participants were randomly assigned tafenoquine (250 mg, 125 mg, 62.5 mg, or 31.25 mg) or placebo daily for 3 days. 417 received initial curative treatment with halofantrine, and 410 completed the assigned prophylaxis regimen. During follow-up of 70 days, adverse events were recorded and thick blood smears were examined weekly. The primary and secondary endpoints were the number of individuals with positive blood smears by day 56 and day 77, respectively. Analyses were per-protocol. FINDINGS: Eight positive blood smears were recorded by day 56 (four/82 participants in the placebo group; four/79 tafenoquine 31.25 mg group). By day 77, 34 positive blood smears had been recorded (14/82 placebo; 16/79 tafenoquine 31.25 mg; three/86 tafenoquine 62.5 mg; one/79 tafenoquine 125 mg; none/84 tafenoquine 250 mg). Numbers of adverse events did not differ significantly between the treatment groups. INTERPRETATION: Tafenoquine is effective and well tolerated. It has the potential to replace currently used drugs for malaria chemoprophylaxis.