Summary of findings 3. 220 mg zinc sulphate supplement containing 50 mg elemental zinc versus placebo for treating foot ulcers in people with diabetes.
| 220 mg zinc sulphate supplements containing 50 mg elemental zinc versus placebo for treating foot ulcers in people with diabetes | ||||||
|
Patient or population: people with diabetes and foot ulcers
Settings: hospital clinic
Intervention: 220 mg zinc sulphate supplement containing 50 mg elemental zinc Comparison: placebo | ||||||
| Outcomes | Illustrative comparative risks* (95% CI) | Relative effect (95% CI) | Number of participants (studies) | Certainty of the evidence (GRADE) | Comments | |
| Assumed risk | Corresponding risk | |||||
| Placebo | 220 mg zinc sulphate supplement containing 50 mg elemental zinc | |||||
|
Ulcer healing (absolute change in individual parameters of ulcer dimensions over time: mean (SD) cm wound length reduction) |
Mean wound length reduction: −0.9 ± 1.2 | Mean wound length reduction: −1.5 ± 0.7 | MD −0.60 (−1.10 to −0.10) | 60 (1 study) | ⊕⊝⊝⊝ Very lowa | Mean wound length reduced by −1.5 ± 0.7 in the 220 mg zinc sulphate supplement containing 50 mg elemental zinc group, and −0.9 ± 1.2 in the placebo group (MD −0.60, 95% CI −1.10 to −0.10). It is uncertain whether 220 mg zinc sulphate supplement containing 50 mg elemental zinc increases the percentage change in wound length over time, because the certainty of the evidence is very low. |
|
Ulcer healing (absolute change in individual parameters of ulcer dimensions over time: mean (SD) cm wound depth reduction) |
Mean wound depth reduction: −0.3 ± 1.0 | Mean wound depth reduction: −0.8 ± 0.6 | MD −0.50 (−0.92 to −0.08) | 60 (1 study) | ⊕⊝⊝⊝ Very lowb | Mean wound depth reduced by −0.8 ± 0.6 in the 220 mg zinc sulphate supplement containing 50 mg elemental zinc group, and −0.3 ± 1.0 in the placebo group (MD −0.50, 95% CI −0.92 to −0.08). It is uncertain whether 220 mg zinc sulphate supplement containing 50 mg elemental zinc increases the percentage change in wound depth over time, because the certainty of the evidence is very low. |
|
Ulcer healing (absolute change in individual parameters of ulcer dimensions over time: mean (SD) cm wound width reduction) |
Mean wound width reduction:−0.8 ± 1.0 | Mean wound width reduction: −1.4 ± 0.8 | MD −0.60 (−1.06 to −0.14) | 60 (1 study) | ⊕⊝⊝⊝ Very lowc | Mean wound width reduced by −1.4 ± 0.8 in the 220 mg zinc sulphate supplement containing 50 mg elemental zinc group, and −0.8 ± 1.0 in the placebo group (MD −0.60, 95% CI −1.06 to −0.14). It is uncertain whether 220 mg zinc sulphate supplement containing 50 mg elemental zinc increases the percentage change in wound width over time, because the certainty of the evidence is very low. |
|
Ulcer healing (proportion of ulcers healed) |
Not reported | |||||
| Quality of life | Not reported | |||||
| Adverse events | Not reported | |||||
| Development of any new foot ulcers | Not reported | |||||
| Amputation rate | Not reported | |||||
| *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% 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; MD: mean difference | ||||||
| GRADE Working Group grades of evidence High certainty: we are very confident that the true effect lies close to that of the estimate of the effect. Moderate certainty: 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 certainty: our confidence in the effect estimate is limited; the true effect may be substantially different from the estimate of the effect. Very low certainty: we have very little confidence in the effect estimate; the true effect is likely to be substantially different from the estimate of effect. | ||||||
aDowngraded two levels for imprecision because of the small sample size and wide confidence intervals; downgraded two levels for indirectness because baseline nutritional status of participants was very poorly reported and the outcomes reported were individual parameters of ulcer dimensions and not ulcer area or volume, it would be possible for one or more of these to change and have the total volume of the wound (for example) remain unchanged.
bDowngraded two levels for imprecision because of the small sample size and wide confidence intervals; downgraded two levels for indirectness because baseline nutritional status of participants was very poorly reported and the outcomes reported were individual parameters of ulcer dimensions and not ulcer area or volume, it would be possible for one or more of these to change and have the total volume of the wound (for example) remain unchanged.
cDowngraded two levels for imprecision because of the small sample size and wide confidence intervals; downgraded two levels for indirectness because baseline nutritional status of participants was very poorly reported and the outcomes reported were individual parameters of ulcer dimensions and not ulcer area or volume, it would be possible for one or more of these to change and have the total volume of the wound (for example) remain unchanged.