Table 1.

Risk of bias assessment

Risk of bias factor	Risk of bias
	High	Low	Unclear
1. Study design	Non-RCT	RCT	Not clearly reported or not reported
2. Site selection	Method of selection of sites within study area not described	Method of selection of sites within study area described	Not clearly reported or not reported
3. Site allocation	Allocation of treatment not performed by random allocation	Allocation of treatment performed by random allocation	Not clearly reported or not reported
4. Blinding of assessors	Not blinded	Blinded	Not clearly reported or not reported
5. Baseline values comparable between sites	Not comparable	Comparable	Not clearly reported or not reported
6. Number of sites	May be inadequate (five to < 20 sites per group) Probably inadequate (< five sites per group or number of sites unknown)	Adequate number of sites (20 or more sites per group)	Not clearly reported or not reported