Verhoef 2002 KEN.

Methods	Trial design: Double‐blind, placebo controlled trial with a 2x2 factorial design Multicentre trial: No Trial duration: 1998 to 2000
Participants	Recruitment: Children were recruited (randomly selected) from communities neighbouring the research clinic in the Mtito Andei Division, Eastern Province, Kenya at the start of the rainy season Inclusion criteria: Age: 2 to 36 months Anaemia: Hb 6.0 to 11.0 g/dL Sickle‐cell anaemia: not reported Other: Temperature < 37.5°C No symptoms suggestive of malaria or anaemia No systemic illness in combination with a blood dipstick result showing current or recent malarial infection Signed consent from parents No allergy to sulfa drugs No history of using drugs containing sulfa in previous 3 weeks Positive dipstick result without symptoms of systemic illness were included Other co‐morbidities: Not reported Sample size: 328 randomized, 307 analysed
Interventions	Total number of intervention groups: 4 IPT (SP) + iron IPT (SP) + iron placebo IPT placebo + iron IPT placebo + iron placebo Dose, and timing of intervention: SP: 1.25 mg pyrimethamine/25 mg sulphadoxine per kg every 4 weeks Iron: ferrous fumerate suspension, targeted dose: 6 mg elemental iron/kg/week administered twice per week Duration of intervention period: 12 weeks Place and person delivering intervention: Iron (or placebo) administered by community health workers twice a week, mothers took children to health workers (place unknown) SP (or placebo) administered by clinical officer Co‐interventions: ITN use: not reported Other: none Additional treatments: Children withdrawn and treated appropriately if they had Hb < 5.0 g/dL Severe and complicated malaria Manifestations of other diseases Children with malaria attacks were treated with amodiaquine or halofantrine if unsuccessful Treated for other common illnesses Co‐interventions equal in each arm? (if not, describe): Yes
Outcomes	Primary outcome: Hb concentration at the end of follow‐up (12 weeks) Proportion of children with at least one malaria attack (defined as presence of fever, that is temperature ≥ 37.5°C, and a positive dipstick result) Secondary outcomes: Anaemia (Hb < 11.0 g/dL) Iron deficiency (serum ferritin concentration < 12 µg/L) Adverse drug reactions Time to first occurrence of malaria attack Measurement time points: Baseline, 4 weeks, 8 weeks, 12 weeks How were outcomes assessed? Capillary blood tested for malaria (dipstick) and Hb measured at each visit (4, 8, 12 weeks) Surveillance and monitoring of illness episodes and adverse effects at twice weekly meetings with community healthworker (questionnaires)
Notes	Country: Kenya Setting: Unclear – rural? Transmission area: Seasonal transmission Source of funding: Netherlands foundation for the Advancement of Tropical Research Conflict of interest stated: Declared no conflicts. Author contacted for follow‐up Hb concentration values
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	"The allocation schedule was generated by one of us (HV) for each block, by means of tables with randomised permutations, and only after acceptance of all children making up a block".
Allocation concealment (selection bias)	Unclear risk	"The order of the children listed in each block was concealed from the person generating the allocation schedule" – unclear, was this not the same person?
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Participants were blinded, placebos and active compounds were indistinguishable in taste and appearance.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	None of the field investigators was aware of the code until after crude analysis and a plan for further analysis had been prepared.
Incomplete outcome data (attrition bias) All outcomes	Low risk	All participants accounted for. Loss to follow‐up rates similar across groups.
Selective reporting (reporting bias)	High risk	Do not report on mean Hb concentrations (primary outcome), only on the difference in Hb concentration between groups.
Other bias	Low risk	No.