Abstract: Eight trials with 316 participants met the inclusion criteria. Most of the included studies were single-centre studies that were carried out in clinics or hospitals with a sample size ranging from 14 to 84. We generally considered the included studies to be at unclear or high risk of bias, as they had one domain at high risk of bias, or three or more domains at unclear risk of bias. We did not identify any studies that reported valid data for time to complete wound healing. Meta-analysis of four studies including 116 participants indicated that participants receiving phototherapy may experience a greater proportion of wounds completely healed during follow-up compared with those receiving no phototherapy/placebo (64.5% for the phototherapy group versus 37.0% for the no phototherapy/placebo group; risk ratio 1.57, 95% confidence interval 1.08 to 2.28; low-quality evidence, downgraded for study limitations and imprecision). Two studies mentioned adverse events in the results; one study with 16 participants suggested that there were no device-related adverse events, and the other study with 14 participants suggested that there was no clear difference between phototherapy and placebo group. Four studies reported change in ulcer size, but primarily due to high heterogeneity, they were not combined. Results from individual trials (including 16 participants to 84 participants) generally suggested that after two to four weeks of treatment phototherapy may result in a greater reduction in ulcer size but the quality of the evidence was low due to unclear risk of bias in the original trial and small sample size. We based the analyses for quality of life and amputations on only one study each (28 participants and 23 participants respectively); both outcomes showed no clear difference between the phototherapy group and the no phototherapy/placebo group. This systematic review of randomised trials suggested that phototherapy, when compared to no phototherapy/placebo, may increase the proportion of wounds completely healed during follow-up and may reduce wound size in people with diabetes, but there was no evidence that phototherapy improves quality of life. Due to the small sample size and methodological flaws in the original trials, the quality of the evidence was low, which reduces our confidence in these results. Large, well-designed randomised controlled trials are needed to confirm whether phototherapy could be an effective option for the treatment of foot ulcers in people with diabetes.

Plain-language summary: We searched for randomised controlled trials comparing different phototherapies, or comparing phototherapy with other treatments or a placebo (sham treatment), for foot ulcers in adults with diabetes in October 2016. We included eight trials (316 participants). Most studies were undertaken in clinics or hospitals and had small numbers of participants (14 to 84). The average age in the included studies was from 53 to 68 years, and the ratio of females to males was 0.46 to 1.88. The included studies compared phototherapy with placebo or no phototherapy, on top of usual care (usual care could include treatments such as dressings, antibiotics, or wound cleaning). Treatment times ranged from 15 days to 20 weeks. The results suggested that phototherapy, when compared to no phototherapy or a placebo, may increase the proportion of wounds completely healed during follow-up and reduce wound size. However, as the included studies involved small numbers of participants and had drawbacks in study methods, our confidence in these results is limited. We did not find sufficient evidence that the potential harms or incidence of amputations differed between the phototherapy group and the no phototherapy/placebo group. We judged the quality of the evidence to be low due to a lack of data and risk of the study results being biased. Further high-quality studies are needed to confirm the benefits and harms of phototherapy. This plain language summary is up to date as of 26 October 2016.