Logan et The researchers and all clinical Aspirin and folic No further information Drop out data provided and Apparently free of Power al. staff involved with patient acid placebo provided largely balanced across two selective outcome calculations (2008)18 randomized list recruitment were blind to this were identical in groups. Folate only reporting - all stated provided but with a size treatment allocation schedule. appearance to intervention - 19 drop outs outcomes reported. required sample of 8, with All medication was active at stage 1 - died (n=4), lost size not met. randomization bottled, labelled and supplied treatments. to follow up (n=5), poor stratified by from the central trial Study health (n=6), patients centre. pharmacy and dispensed to participants, refused (n=4). 54 drop outs patients through regional clinical staff at stage 2 - withdrew from pharmacies at each involved with both medication arms participating centre. patient (n=42), withdrew from surveillance and aspirin only (n=11), investigators at withdrew from folic acid the coordinating only (n=1); Placebo centre were all Intervention - 29 drop outs blind to at stage 1 - died (n=7), lost treatment. Only to follow up (n=7), poor pharmacists health (n=7), patient had knowledge refused (n=8). 46 drop outs of treatment. at stage 2 - withdrew from both medication arms (n=25), withdrew from aspirin only (n=21). Wu et al. Random No information provided. No blinding of Drop out figures were Apparently free of selective No inclusion of power calculations. (2009)20 number participants provided and reasons for outcome reporting - all generator because the drop out reported. stated outcomes reported. control group Difference in drop out received no figures between groups: placebo n=41 discontinued folic supplement. acid intervention v n=62 in intervention group. Similar numbers in final analysis cohorts (n=237 in folic acid intervention and n=238 in cohort). Although number of subjects excluded from analysis were similar in both groups it was not explained how these related to drop out
Logan et al. (2008)18 randomized list with a size of 8, with randomization stratified by centre. The researchers and all clinical staff involved with patient recruitment were blind to this treatment allocation schedule. All medication was bottled, labelled and supplied from the central trial pharmacy and dispensed to patients through regional pharmacies at each participating centre. Aspirin and folic acid placebo were identical in appearance to active treatments. Study participants, clinical staff involved with patient surveillance and investigators at the coordinating centre were all blind to treatment. Only pharmacists had knowledge of treatment. No further information provided Drop out data provided and largely balanced across two groups. Folate only intervention - 19 drop outs at stage 1 - died (n=4), lost to follow up (n=5), poor health (n=6), patients refused (n=4). 54 drop outs at stage 2 - withdrew from both medication arms (n=42), withdrew from aspirin only (n=11), withdrew from folic acid only (n=1); Placebo Intervention - 29 drop outs at stage 1 - died (n=7), lost to follow up (n=7), poor health (n=7), patient refused (n=8). 46 drop outs at stage 2 - withdrew from both medication arms (n=25), withdrew from aspirin only (n=21). Apparently free of selective outcome reporting - all stated outcomes reported. Power calculations provided but required sample size not met. Wu et al. (2009)20 Random number generator No information provided. No blinding of participants because the control group received no placebo supplement. Drop out figures were provided and reasons for drop out reported. Difference in drop out figures between groups: n=41 discontinued folic acid intervention v n=62 in intervention group. Similar numbers in final analysis cohorts (n=237 in folic acid intervention and n=238 in cohort). Although number of subjects excluded from analysis were similar in both groups it was not explained how these related to drop out Apparently free of selective outcome reporting - all stated outcomes reported. No inclusion of power calculations.