DEVTA (1999 - 2004; first results 2007):
The world's largest-ever randomised trial
2x2 cluster-randomised trial of De-worming and Enhanced Vitamin A (DEVTA) in one million rural children in the state of Uttar Pradesh (UP) in north India. Principal investigator: Dr Shally Awasthi, King George's Medical University, Lucknow, India.
Units of randomisation: 72 development blocks
18 allocated 6-monthly vitamin A (200,000 IU)
18 allocated 6-monthly de-worming (400mg albendazole)
18 allocated both
18 allocated neither
Study population within blocks: all the children aged up to 6 years in all the functioning pre-school (anganwadi) centres in the block; mean about 10-20,000 children per block, total (72 blocks) about 1 million children.
Intervention: once every 6 months for 5 years, select an intervention day and get the existing anganwadi workers to treat all then aged 6 months to 6 years.
Main outcome: mortality between ages 1.0 and 6.0.
Main analyses: compare 36 vs 36 cluster-specific results (72 data points only, and so of correspondingly limited sensitivity).
- 36 vit A vs 36 no vit A blocks
- 36 de-worming vs 36 no de-worming blocks
No significant interactions between the effects of the two treatments on major outcomes (so any analyses of 18 vs 18 blocks would be subsidiary analyses).