Number of studies published each year

WWARN Clinical Trials Publication Library

A comprehensive compilation of all antimalarial clinical efficacy trials conducted and published since 1960

Between January 1960 to October 2016 a total of 1,312 published clinical efficacy studies could be identified, of which more than 85% of the studies were available for in-depth analysis. You can now download a WWARN publication library of the references and the key parameters of these studies. 

The highlights are detailed below:

  • The overall median time from end of study enrolment to publication is 2 years
  •  Where described 54% of studies enrolled children under 5 years, 56% children aged 5-15 years and 64% adults. In total 57 (5%) of the studies enrolled pregnant women. 581 (53%) studies were randomised and 89 (10%) blinded.

Figure 1 graph

Figure 1 reveals the trends in annual publicatio0n, highlighting a steady increase in publications until the mid 2000s.

 

 

Figure 2 also displays the number of publications each year but distinguished by parasite species. Studies that included P. falciparum either alone or in infections mixed with any other species are presented in blue. Those reporting only P. vivax infections are shown in red. Overall 70% of studies assessed P. falciparum efficacy and 18% P. vivax (17% of studies were either unavailable or the species was not documented).

 

Figure 3 shows the temporal trends in publications according to the region in which the trial was conducted. In total 50% (637) of studies were conducted in Africa, 42% (535) in Asia, with 7% (88) carried out in South America.

 

Figure 4 represents the number of trials focused exclusively on artemisinins or ACTs.  Since 1984 the analysis reveals 494 clinical studies that report on ACT efficacy. The cumulative proportion of clinical studies of P. falciparum malaria involving an ACT rose from 26% (6/23) in 2000 to 77% (37/48) in 2011. This rise is particularly noticeable in studies from Africa, where almost all studies now involve an ACT. In contrast, clinical trials in Asia continue to recruit and treat patients with uncomplicated malaria with monotherapies (for further details see the (excel) Treatment worksheet within the WWARN publication library.
 

Figure 5 presents the duration of study follow up. Overall the majority of trials (56%) used a 28 day follow up. In the 1980s and 1990s, 25% of studies followed patients for 14 days or less. However the WHO guidelines were revised in 2001 and again in 2009 recommending a minimum of 28 days follow up. In the last 5 years the proportion of short duration studies fell to 2.6% (2/78).

Clinical Trial Maps display where published trials took place. Each pin represents a single site where patients were recruited as part of an antimalarial clinical trial.

Find out more about the methodology behind this literature review.