Summary of findings 3. Quinine versus a quinine‐vitamin E combination (Q‐Vel) for muscle cramps.
| Quinine versus a quinine‐vitamin E combination (Q‐Vel) for muscle cramps | ||||||
| Patient or population: people with muscle cramps Settings: outpatients Intervention: quinine versus a quinine‐vitamin E combination (Q‐Vel) | ||||||
| Outcomes | Illustrative comparative risks* (95% CI) | Relative effect (95% CI) | No of Participants (studies) | Quality of the evidence (GRADE) | Comments | |
| Assumed risk | Corresponding risk | |||||
| Quinine‐vitamin E combination (Q‐Vel) | Quinine | |||||
| Number of cramps over 2 weeks | The mean number of cramps over 2 weeks in the control groups was 8.37 | The mean number of cramps over 2 weeks in the intervention groups was 1.07 higher (1.08 lower to 3.23 higher) | 486 (2 studies) | ⊕⊕⊝⊝ low1,2 | The difference was not statistically significant. | |
| Cramp intensity (on 3‐point scale; 1 = mild; 2 = moderate; 3 = severe) | The mean cramp intensity in the control groups was 0.87 units | The mean cramp intensity in the intervention groups was 0.1 higher (0.06 lower to 0.26 higher) | 510 (3 studies) | ⊕⊕⊝⊝ low3,4 | The difference was not statistically significant. | |
| Participants suffering major adverse events | 8 per 1000 | 8 per 1000 (‐2 to 18) | See comment | 510 (3 studies) | ⊕⊕⊕⊝ moderate3 | Risks were calculated from pooled risk differences. |
| Participants suffering minor adverse events | 173 per 1000 | 202 per 1000 (133 to 273) | See comment | 510 (3 studies) | ⊕⊕⊕⊝ moderate3 | Risks were calculated from pooled risk differences. The difference was not statistically significant. |
| *The basis for the assumed risk (e.g. the median control group risk across studies) is provided in footnotes. The corresponding risk (and its 95% CI) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). CI: confidence interval | ||||||
| GRADE Working Group grades of evidence High quality: Further research is very unlikely to change our confidence in the estimate of effect. Moderate quality: Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate. Low quality: Further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate. Very low quality: We are very uncertain about the estimate. | ||||||
1The results for cramp number in these 2 trials were not consistent, each suggesting opposite effects. 2Only 2 studies were available for this comparison. Both were conducted by pharmaceutical investigators on behalf of manufacturers of quinine and the quinine‐vitamin E combination. 3All 3 trials were conducted by pharmaceutical companies who manufacture quinine and the quinine‐vitamin E combination. 4There was no consistency between the results for intensity in these 3 trials.