Friday October 10 2008
“Honey has been found to be better at aiding burn recovery than standard treatments used by the NHS,” the Daily Mail reported. The newspaper said that scientists had pooled data from 19 trials involving more than 2,500 patients with various wounds. They found that mild to moderate burns took less time to heal when honey was applied than some widely used dressings.
This review was carried out by the Cochrane Collaboration and is a very thorough investigation of the existing research on the use of honey in treating wounds. It found that honey might improve healing times in some types of burn (thin burns which are mild to moderate, superficial and of partial thickness) compared with some conventional dressings. The researchers say this finding should be treated with caution, however, and that "Health services should invest in treatments that have been shown to work". Other supposed applications of honey proved to be less effective. For example, honey dressings used under compression bandages did not significantly increase leg ulcer healing after 12 weeks. The authors suggest that this practice should stop, and that there is insufficient evidence to guide clinical practice for other wound types.
Where did the story come from?
Dr Andrew Jull and colleagues from the Clinical Trials Research Unit at the University of Auckland in New Zealand carried out the systematic review. There were no external sources of support for the study. The study was published in the Cochrane Database of Systematic Reviews, a publication of the Cochrane Collaboration.
What kind of scientific study was this?
This was a systematic review of trials, which aimed to determine whether honey increases the rate of healing in acute wounds (burns, lacerations and other traumatic wounds) and chronic wounds (venous ulcers, arterial ulcers, diabetic ulcers, pressure ulcers and infected surgical wounds).
As background, the researchers note that honey is a sticky “supersaturated” sugar solution derived from nectar gathered and modified by the honeybee and used since ancient times as a remedy in wound care. Recent trials have evaluated the effects of using honey to help wound healing, but it was not known if it helps both new wounds, such as burns and lacerations, and long-term wounds, such as venous leg ulcers and pressure ulcers. How honey works is also unknown, although recent research has concentrated on the antibacterial activity of the many varieties of honey, rather than their effect on wound healing. One theory is one that Manuka honey (from New Zealand and Australia) has unique antibacterial activity independent of the effect of honey’s general peroxide (an anti-bacterial property) activity and its osmolarity (its thickness and stickiness).
The researchers first searched recognised literature databases for studies published before May 2008. The search included the Cochrane Wounds Group Specialised Register, a controlled trial register called CENTRAL, and several other electronic databases. This list of trials was supplemented with any studies listed in reference lists and any unpublished trials from the manufacturers of dressing products.
In order that only high-quality trials were included, the search was restricted to randomised and quasi randomised trials, those that had evaluated honey as a treatment for any sort of acute or chronic wound, and those where wound healing was the main outcome that was measured. Studies were included irrespective of where they were published, their date of publication or language.
What were the results of the study?
The search identified 19 trials with a total of 2,554 participants to be included in the review. Three trials evaluated the effect of honey on acute lacerations, abrasions or minor surgical wounds. Nine trials evaluated the effect of honey on burns. Two other trials evaluated the effect of honey on venous leg ulcers, and there was one trial each on pressure ulcers, infected post-operative wounds, and Fournier’s gangrene. Two trials recruited people with mixed groups of chronic or acute wounds.
In the trials of partial thickness burns, the researchers found that honey reduced healing time to healing by 4.68 days compared with some conventional dressings (95% CI -4.28 to -5.09 days).
In chronic wounds, honey dressings used under compression bandaging did not significantly increase healing in venous leg ulcers (RR 1.15, 95%CI 0.96 to 1.38).
There was insufficient evidence to determine the effect of honey compared with other treatments for burns or in other acute or chronic wound types.
What interpretations did the researchers draw from these results?
The researchers say that “honey may improve healing times in mild to moderate superficial and partial thickness burns compared with some conventional dressings”.
They also say that when honey dressings are used under compression bandaging, there is no significant increase in leg ulcer healing at 12 weeks, and there is insufficient evidence to guide clinical practice in other areas.
What does the NHS Knowledge Service make of this study?
The researchers acknowledge that the poor quality of most of the trial reports means the results should be interpreted with caution. The exception to their overall conclusion is for venous leg ulcers, where they are confident that honey dressings used under compression bandaging is not justifiable or worthwhile. There are other points to note about this review:
- The researchers report that all nine burns trials that were included originated from a single centre – the department of surgery at a medical college in Maharashtra, India, and up until 1999 have the same single author, Dr M Subrahmanyam. The researchers warn that this may have an impact on whether or the studies could be replicated, meaning that there may be specific details regarding how the honey dressings were applied in this centre that may not be repeatable in other centres.
- Some of the trials included were quasi-randomised, meaning that in some cases the participants were allocated to alternate groups based on the day of attendance at the hospital. This can affect the reliability of the findings from these trials as it is possible for bias to occur. For example, the investigators could have influenced who went into which group.
- The researchers had to use the outcomes reported in the trials, and these were usually the average (mean) time to healing. They say that this is not the most appropriate method of analysing this sort of ‘time to event’ data, and that survival analysis would have been more appropriate.
- Pooling of results for analysis can be a controversial area in systematic reviews, and these authors comment that two of their analyses had highly significant heterogeneity. This means that the trials were different enough from each other to suggest that combining the results may be problematic. They justify the pooling of results on clinical and methodological grounds, and said that to do otherwise would have breached the protocol that they had already decided upon.
This is a thorough review, which by its design will have identified the major trials of honey treatment for wounds. The researchers were particularly thorough in that they attempted to contact authors where data was missing. Several avenues for future research are identified by the researchers. Where there is still doubt about the effectiveness of honey as a dressing for thin burns, they welcome more well-designed randomised trials.