Rybo 1971.
| Methods |
Type of study: parallel, 3‐arm randomised controlled trial Country of study: Sweden Study setting: hospital blood bank Number of participants randomised: Treatment arm 1: 460 (261 male, 199 female) Treatment arm 2: 460 (260 male, 200 female) Treatment arm 3: 456 (257 male, 199 female) Number of participants analysed: Treatment arm 1: 392 (212 male, 180 female) Treatment arm 2: 389 (214 male, 175 female) Treatment arm 3: 385 (205 male, 180 female) Follow‐up time points: 14 days post‐donation Hb threshold for deferral from donation: not reported Source of funding: not reported |
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| Participants | Regular blood donors Mean age (years): not reported Sex (male/female): Treatment arm 1: 56.7%/63.3% Treatment arm 2: 56.5%/63.5% Treatment arm 3: 56.4%/63.6% |
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| Interventions | Treatment arm 1: oral ferrous sulphate (AB Hassle, Goteborg); 100 mg taken twice daily for 14 days. Total dose: 2800 mg Treatment arm 2: oral iron (AB Hassle, Goteborg) as 100 mg sustained‐release tablets (40% iron release within 1 hour and 100% within 6 hours) taken twice daily for 14 days. Total dose: 2800 mg Treatment arm 3: oral placebo (AB Hassle, Goteborg) taken twice daily for 14 days. Total dose: 2800 mg |
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| Outcomes | Adverse effects; compliance | |
| Notes | — | |
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Unclear risk | The method of randomisation was not reported |
| Allocation concealment (selection bias) | Low risk | "Subjects received tablets in a coded bottle labelled 'iron tablets to blood donors'" |
| Blinding of participants and personnel (performance bias) All outcomes | Low risk | "Subjects received tablets in a coded bottle labelled 'iron tablets to blood donors'" |
| Blinding of outcome assessment (detection bias) All outcomes | Unclear risk | Blinding of outcome assessors was not reported |
| Incomplete outcome data (attrition bias) All outcomes | Low risk | The number of randomised participants with missing data was similar in each group (68/460 versus 61/460) with less than 5% difference in attrition rate between treatment arms) |
| Selective reporting (reporting bias) | Unclear risk | All outcomes listed in the manuscript were reported, but no study protocol was available to determine the full list of pre‐specified outcomes |
| Other bias | Low risk | No other sources of bias identified |