Data analysis
diarrhoea, nausea, fever, abdominal pain, malaria, vomiting, dizziness, parasitaemia, anorexia
REGRESSION, MALARIA, ANOREXIA
The number and proportion of patients who had the most clinically relevant symptoms (vomiting, diarrhoea, anorexia, nausea, abdominal pain and dizziness) following the administration of primaquine or placebo are presented by study site and treatment. The confounder-adjusted proportion of the presence of each symptom at least once between day 0 and 13 for each study site was estimated following multivariable logistic regression with each confounder (age, sex, day 0 parasitaemia, treatment arm, and presence of fever on day 0) set at the population mean/prevalence value of the overall trial. Schizontocidal treatment was not adjusted for due to collinearity with study site (chloroquine for all patients in Ethiopia, Vietnam and Afghanistan, dihydroartemisinin-piperaquine for patients in Indonesia). A sensitivity analysis was performed excluding patients less than 5 years, whose parents or guardians may have reported their symptoms.To explore whether the observed variation between study sites may be due to differences in acute malaria symptoms the analyses were repeated for each symptom restricted to the time after acute malaria symptoms are expected to subside (days 3 to 13). To further explore whether the reported presence or absence of symptoms in an individual on day 0 or 1 could explain the variation between study sites, the models were repeated including symptom presence on day 0 or 1 as a covariate.To investigate whether variation in symptom reporting was impacted by severity, the presence of severe symptoms (grade 3) was compared between study sites. The confounder-adjusted proportion of symptoms between day 3 and 13 was described for each treatment arm using the previous multivariable logistic regression model and compared across sites to explore within and between-study site variation in symptoms.All statistical analyses were performed using Stata version v17.0 (StataCorp, US). Confounder-adjusted proportions of symptoms were estimated using the margins command.