Summary of findings 2. Fractional laser versus radiofrequency for acne scars.

Fractional laser versus radiofrequency for acne scars
Patient or population: people with acne scars Settings: hospital‐based Intervention: fractional laser versus radiofrequency
Outcomes	Illustrative comparative risks* (95% CI)		Relative effect (95% CI)	No of Participants (studies)	Quality of the evidence (GRADE)	Comments
	Assumed risk	Corresponding risk
	Control	Fractional laser versus radiofrequency
Participant‐reported scar improvement (long‐term)	See comment	See comment	Not estimable	‐	See comment	This outcome was not measured
Participant‐reported scar improvement (short‐term) N of participants with > 50% improvement in acne scars Follow‐up: mean 8 weeks	450 per 1000	351 per 1000 (162 to 756)	RR 0.78 (0.36 to 1.68)	40 (1 study)	⊕⊝⊝⊝ very low1,2	Rongsaard 2014 reported a mean improvement of 2.89 for the fractional laser and 2.74 for the radiofrequency
Investigator‐assessed adverse events (short‐term)	See comment	See comment	Not estimable	‐	See comment	Unclear whether the reported higher events (erythema, oedema, PIH) with the laser are participant‐ or investigator‐assessed
Participant‐assessed adverse events (short‐term)	See comment	See comment	Not estimable	‐	See comment	More pain with fractional laser was noticed, Rongsaard 2014 and Zhang 2013 reported higher incidence of positive adverse events with fractional laser
Participant satisfaction	See comment	See comment	Not estimable	‐	See comment	Zhang 2013 reported that 30/33 and 31/33 of participants were satisfied with laser and radiofrequency respectively with no significant difference
Quality of life	See comment	See comment	Not estimable	‐	See comment	This outcome was 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.

¹Downgraded by one level because of unclear allocation concealment and high blinding of participant and personnel.
 ²Downgraded two levels for very serious imprecision because the optimal information size (OIS) is not met (should be around 620) and the 95% CI around the estimate of effect includes both no effect and appreciable benefit.