Characteristics of all non-infectious disease (ID) studies, all ID Studies, and HIV-AIDS, hepatitis C, malaria, and tuberculosis studies registered with ClinicalTrials.gov from October 2007–September 2010.

The denominator for each variable is the number of trials reporting such data. “Other Purpose” includes “Diagnostic”, “Supportive Care”, “Screening”, “Health Services Research”, and “Basic Science”. For Intervention type, the numerator is the number of trials with at least 1 intervention of this type. A study with multiple interventions may be represented in more than 1 intervention type; hence, cumulative percentage will exceed 100%. “Other Intervention” includes “Radiation”, “Dietary Supplement”, and “Genetic”. The “Comparator” variable identifies the number of trials designating that particular comparator. Since a study may have both a placebo and an active comparator arm, the cumulative percentage may exceed 100%. The “Recruiting” variable under “Overall Status” includes trials recruiting by invitation. “Terminated” includes trials that have been terminated, suspended, or withdrawn. The numerator in the regional distribution variable is the number of trials with at least 1 study site in that respective region. A multisite study may be represented in more than 1 region; hence the cumulative percentage will exceed 100%. Abbreviations: DMC, data monitoring committee; ID, infectious diseases; IQR, interquartile range; NIH = US National Institutes of Health.aChildren defined as ≤18 years of age.bElderly defined as >65 years of age.cIndividual countries by region are available at: http://www.clinicaltrials.gov/ct2/search/browse?brwse=locn_cat.