| Methods |
Double‐blind RCT of cross‐over design, conducted at a Veterans Affairs Medical Center in USA |
| Participants |
30 male participants (aged 38 to 73 years) who experienced at least 6 leg cramps per month |
| Interventions |
Quinine sulphate 500 mg daily (200 mg at supper, 300 mg at bedtime) or vitamin E 800 U daily or placebo for a 4‐week treatment period, followed by a 4‐week washout period before cross‐over to a second 4‐ week treatment period |
| Outcomes |
Cramp number, cramp nights, cramp intensity (graded 1 = no pain to 4 = severe), sleep disturbance (graded 1 = none to 4 = severe), adverse events |
| Notes |
|
| Risk of bias |
| Bias |
Authors' judgement |
Support for judgement |
| Random sequence generation (selection bias) |
Unclear risk |
Quote: "Drug‐on periods were assigned in randomly permuted order..."
Comment: details of randomisation not provided |
| Allocation concealment (selection bias) |
Unclear risk |
No details provided on how allocation may have been concealed |
| Blinding (performance bias and detection bias)
All outcomes |
Low risk |
Quote: "All medications were packaged in unit doses and dispensed by the same company." Comment: probably adequate blinding |
| Incomplete outcome data (attrition bias)
All outcomes |
Low risk |
All 3 participants who failed to complete the study were accounted for |
| Selective reporting (reporting bias) |
Low risk |
All outcome measures mentioned in the protocol were addressed in the analysis |
| Other bias |
Unclear risk |
All subjects were men as all recruited from Veterans Affairs Medical Center |
