Davis 2000.
Methods | Randomised, placebo‐controlled trial | |
Participants | 28 adult men and women with symptomatic RLS currently on treatment, enrolled from a single neurology clinic (USA) | |
Interventions | Intervention: ferrous sulfate liquid 325 mg twice a day Placebo: a 50:50 mixture of water and 2% carboxymethlycellulose with a "slightly disagreeable taste, similar to liquid ferrous sulfate". Study drug continued through week 16, then extended an additional 10 weeks if participants preferred study drug to their previous RLS medication |
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Outcomes | VAS of the extent that RLS interferes with sleep; VAS of how RLS affects life, ferritin, gastrointestinal side effects | |
Notes | Power for primary outcome was 25% | |
Risk of bias | ||
Bias | Authors' judgement | Support for judgement |
Random sequence generation (selection bias) | Unclear risk | Block randomisation, but method not specified |
Allocation concealment (selection bias) | Low risk | Randomisation controlled by nurse not involved in the study; randomisation key in locked cabinet |
Blinding (performance bias and detection bias) All outcomes | Low risk | Investigators and participants blinded; placebo and iron both liquids with slightly disagreeable taste |
Incomplete outcome data (attrition bias) All outcomes | High risk | 6 of 14 iron‐treated participants left before primary and secondary outcomes measured at week 14 (versus 1 of 14 placebo‐treated participants). Study data only reported for the people who remained |
Selective reporting (reporting bias) | Unclear risk | No study protocol available |
Other bias | Low risk | No other risks identified |