TABLE 2.
Summary of findings and strength of evidence.
| Melasma outcomes | No. of included trials (sample size) | Effect estimates (95% CI) | p-value | Heterogeneity | Strength of evidence (outcome classification) | |||
|---|---|---|---|---|---|---|---|---|
| Q statistic | p-value | I 2 index (95% CI) | τ2 | |||||
| (A) Compared with active-controlled (triple combination cream: Kligman’s formula) | ||||||||
| Treatment efficacy at 8 weeks | ||||||||
| Change in the MASI score from baseline | 2 (80) | MD: 0.19 (−0.25–0.63) | 0.390 | 0.58 | 0.448 | 0.0% (NA) | <0.001 | Low (trivial, not different from Kligman’s formula) |
| Moderate to total global improvement (improvement in MASI score >25%) | 2 (80) | OR: 0.90 (0.30–2.72) | 0.848 | 1.08 | 0.299 | 7.3% (NA) | 0.073 | Low (trivial, not different from Kligman’s formula) |
| Treatment satisfaction: satisfied to highly satisfied | 2 (80) | OR: 1.00 (0.23–4.31) | 1.000 | <0.01 | 1.000 | 0.0% (NA) | <0.001 | Low (trivial, not different from Kligman’s formula) |
| Safety profiles at 8 weeks | ||||||||
| Unacceptability of treatment (all-cause study dropout) | 2 (80) | Not estimated (no participant dropout during trial follow-up of 8 weeks) | Insufficient data | |||||
| Tolerability (dropout due to adverse events) | 2 (80) | Not estimated (no participant dropout during trial follow-up of 8 weeks) | Insufficient data | |||||
| Serious adverse events | 2 (80) | Not estimated (no participant dropout during trial follow-up of 8 weeks) | Insufficient data | |||||
| Any adverse events | 2 (80) | OR: 0.32 (0.07–1.51) | 0.148 | 0.51 | 0.474 | 0.0% (NA) | <0.001 | Low (trivial, not different from Kligman’s formula) |
| (B) Compared with placebo | ||||||||
| Treatment efficacy | ||||||||
| Change in the MASI score from baseline at 8 weeks | 1 (60) | MD: −0.56 (−1.07 to −0.04) | 0.034 | NA | NA | NA | NA | Very low (beneficial with topical metformin) |
| Change in the MASI score from baseline at 12 weeks | 1 (60) | MD: −0.73 (−1.25 to −0.20) | 0.007 | NA | NA | NA | NA | Very low (beneficial with topical metformin) |
| Safety profiles at 12 weeks | ||||||||
| Unacceptability of treatment (all-cause study dropout) | 1 (60) | Not estimated (no participant dropout during trial follow-up of 12 weeks) | Insufficient data | |||||
| Tolerability (dropout due to adverse events) | 1 (60) | Not estimated (no participant dropout during trial follow-up of 12 weeks) | Insufficient data | |||||
| Serious adverse events | 1 (60) | Not estimated (no specific serious adverse events reported) | Insufficient data | |||||
| Any adverse events | 1 (60) | Not estimated (no specific adverse events reported) | Insufficient data | |||||
Abbreviations: CI, confidence interval; MASI, melasma area and severity index; NA, not applicable; OR, odds ratio; MD, mean difference.