Interventions for the Treatment of Stretch Marks: A Systematic Review
Stretch marks are a common disfiguring skin condition that can have a deep psychological impact on affected patients. Although there are a variety of treatments available, no consistently effective therapies have been established. In this systematic review, we evaluate 8 randomized controlled trials (RCTs) to assess the efficacy and safety of currently available therapies for the treatment of stretch marks. Due to the limited number of patients and high or unclear risk of bias in the studies included in this assessment, the evidence from this review is insufficient to provide clear guidelines for practice. Therefore, more high-quality RCTs are needed.
Practice Points
- Given the negligible reported side effects, tretinoin cream 0.1%, a cosmetic oil formulation, onion extract cream, or the combined use of Active A and Active B could be considered for the treatment of stretch marks, though the evidence is insufficient.
- High-quality, randomized, placebo-controlled trials are needed in the future.
Risk of Bias
The risk of bias in methodology was evaluated for all 8 RCTs and the judgments were given for each domain (Figure 2). All the included studies claimed to be RCTs, but only 37.5% (3/8) of them used adequate randomizations, which were from a including computer-generated code,10 a table of randomized numbers,13 or the Microsoft Excel RND function (from the author by e-mail).14 The randomization methods in the other 5 studies were unclear. Allocation concealment was adequate in 1 trial13 but was unclear in the others. Three trials were double-blinded with the participants and outcome assessors blinded10,13,16; in 2 of these studies investigators also were blinded.10,13 There were 5 single-blinded trials; in 3 of these trials the outcome assessors were blinded12,14,15 and 1 was investigator-blinded.9 The other study was stated to be single-blinded but with no further detail.11 Due to the nature of the experimental design in 2 of the trials12,15 (ie, effects of laser therapy compared to topical treatment or no therapy), participants could not be blinded to treatment types; however, participants were blinded in 1 trial that compared different types of lasers.16 Investigators from all studies reported participants who did not complete the trial or were lost to follow-up, ranging from 0% to 65.6%. Two trials reported no loss of follow-up.11,12 Most trials had losses less than 20% except Pribanich et al13 who reported a loss of 65.6% of participants. One trial included a full analysis set,9 and none of the studies included an intention-to-treat analysis.
The overall risk of bias was assessed for each study and none could be categorized as low risk. Six studies had 1 or more domains assessed as high risk of bias and were classified as high risk of bias.9,11-15 The remaining 2 studies without high-risk domains had one or more domains assessed as unclear10,16 and were therefore considered to be at unclear risk of bias overall.
