5. Azelaic acid compared to placebo.
| Azelaic acid compared to placebo for acne | ||||||
| Patient or population: participants with acne Settings: not described (4 studies) Intervention: topical azelaic acid Comparison: placebo | ||||||
| Outcomes | Illustrative comparative risks* (95% CI) | Relative effect (95% CI) | No. of participants (studies) | Quality of the evidence (GRADE) | Comments | |
| Assumed risk | Corresponding risk | |||||
| Placebo/no treatment | Topical azelaic acid | |||||
| Participants' global self‐assessment of acne improvement | ‐ | ‐ | ‐ | ‐ | ‐ | Not measured |
|
Withdrawal for any reason (long term: treatment duration > 8 weeks) |
63 per 1000 | 101 per 1000 (35 to 295) | RR 1.60 (0.55 to 4.66) | 152 (3 studies) | ⊕⊕⊝⊝ Lowa | ‐ |
|
Total number of participants who experienced at least one minor adverse event (medium term: treatment duration from 5 to 8 weeks) |
See comment | See comment | RR 19.00 (1.16 to 312.42) | 60 (1 study) | ⊕⊝⊝⊝ Very lowb | 9/30 versus 0/30 experienced minor adverse events. In the other studies in this comparison, events such as scaling, dry skin, erythema, oiliness, and pruritus were reported, but the number of participants with these events were low and similar across groups. |
| Quality of life | ‐ | ‐ | ‐ | ‐ | ‐ | Not measured |
| *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; RR: risk ratio. | ||||||
| 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. | ||||||
aDowngraded by two levels to low quality evidence. One level for risk of bias: three studies included, two with unclear risk of selection bias and one with unclear risk of allocation concealment, one study with high risk of reporting bias and one with high risk of attrition bias. One level for imprecision: wide CI and optimal sample size not met. bDowngraded by three levels to very low quality evidence. One level for risk of bias: only one study included, and study with unclear random sequence generation and allocation concealment. Two levels for imprecision: wide CI and optimal sample size not met. *We choose a mean baseline risk from the studies included in meta‐analysis, calculated as number of participants in the control groups with event divided by total number of participants in control groups (study population) as assumed risk.