Summary of findings 2. Low frequency ultrasound compared with no ultrasound for people with venous leg ulcers.
| Low frequency ultrasound compared with no ultrasound for people with venous leg ulcers | ||||||
| Patient or population: venous leg ulcers Setting: any Intervention: low frequency ultrasound Comparison: no ultrasound | ||||||
| Outcomes | Anticipated absolute effects* (95% CI) | Relative effect (95% CI) | № of participants (studies) | Quality of the evidence (GRADE) | Comments | |
| Risk with no ultrasound | Risk with Low frequency US | |||||
| Proportion of ulcers completely healed at 8 to 12 weeks | Study population | RR 3.91 (0.47 to 32.85) | 61 (2 RCTs) | ⊕⊝⊝⊝ VERY LOW 1, 2 | There were no events in the control groups so we added 0.5 to the cell as a fixed value (as per Cochrane Handbook). Highly uncertain whether low frequency ultrasound affects healing at 8 to 12 weeks. | |
| 17 per 1000 | 65 per 1000 (8 to 548) | |||||
| High3 | ||||||
| 300 per 1000 | 1000 per 1000 (141 to 1000) | |||||
| Adverse events | No study reported adverse events | Pain was reported; however, this does not appear to have been measured systematically. | ||||
| HRQoL | No study reported HRQoL | |||||
| Cost | No study reported cost | |||||
| *The risk in the intervention group (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). CI: confidence interval; HRQoL: health‐related quality of life; RR: risk ratio; OIS: Optimal information size | ||||||
| GRADE Working Group grades of evidence High quality: We are very confident that the true effect lies close to that of the estimate of the effect Moderate quality: We are moderately confident in the effect estimate: The true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different Low quality: Our confidence in the effect estimate is limited: The true effect may be substantially different from the estimate of the effect Very low quality: We have very little confidence in the effect estimate: The true effect is likely to be substantially different from the estimate of effect | ||||||
1 Downgraded due to risk of bias (one level) because both studies were at unclear or high risk
2 Downgraded due to imprecision (two levels): the OIS is hard to reach; very wide 95% CIs ‐ ranging in the ultrasound group from a 53% reduction of risk for ulcer healing to a 3285% increased risk (Guyatt 2011)
3 With best practice (i.e. high compression bandaging), a baseline risk of healing at 10 weeks (midpoint of 8 and 12 weeks) would be approximately 30% (Iglesias 2004)