| Methods |
Double blind, parallel group RCT |
| Participants |
40 non‐pregnant rest cramp sufferers (45 to 80 years of age) with normal renal function having at least 2 cramps per week that were rated 5 or more on a 0‐10 pain scale. Recruitment by radio advertisement in an American (State of Michigan) population. |
| Interventions |
Either 168 mg elemental magnesium from slow release magnesium lactate tablets (MagTabSR) or matching placebo tablets taken orally twice daily for 30 days. |
| Outcomes |
Frequency, duration and severity of leg cramps captured daily x 1 wk pre‐intervention and daily during the 30 days of intervention (via diary recording of cramps and sleep disturbance). Pittsburgh Sleep Quality questionnaire also administered pre‐ and post‐intervention. |
| Notes |
Unpublished. Sponsorship not provided. Incomplete results reporting. Patient level data for cramp frequency were kindly provided by study statistician. |
| Risk of bias |
| Bias |
Authors' judgement |
Support for judgement |
| Random sequence generation (selection bias) |
Unclear risk |
Stated as randomized but details not provided. |
| Allocation concealment (selection bias) |
Unclear risk |
No details provided. |
| Blinding (performance bias and detection bias)
All outcomes |
Low risk |
Quote: "Masking: Double Blind (Subject, Investigator, Outcomes Assessor)". No details provided. Probably adequate. |
| Incomplete outcome data (attrition bias)
All outcomes |
Low risk |
Small number of dropouts, two from magnesium and one from placebo. Reasons not provided. |
| Selective reporting (reporting bias) |
High risk |
Patient level data were provided to us but were only available for a subset of the outcomes. |
| Cramp diary (recall bias) |
Low risk |
Diary used |
| Other bias |
Low risk |
No obvious other bias |
