Efficacy of topical cadexomer iodine treatment in chronic wounds

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The latest evidence supporting the use of  IODOSORB is discussed and  how this can be applied to clinical practice.

Disclaimer: IODOSORB gel is not available in ANZ.

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Welcome to Smith and Nephew's Close to Zero podcast, a bi-monthly podcast with leading experts from Wound  Care, hosted by Smith and Nephew, helping health care professionals in reducing the human and economic cost of wounds. 00:00:00


Hello, I'm Ruth Timmins and welcome to today's podcast. Today, we'll be discussing the exciting news about the recently published systematic review and meta- analysis of the clinical efficacy of topical cadexomer iodine in the treatment of chronic wounds. Today, we're pleased to have some of the authors of this new meta-analysis with us. And so we'd like to welcome Dr Kevin Woo, who's an Associate Professor at Queens University in Ontario, Canada and Ben Costa, who is a clinical evidence specialist from Smith and Nephew. So, it's wonderful to have you both with us to be able to discuss this new published work around the evidence, for IODOSORB or cadexomer iodine. So perhaps firstly, Kevin could you give me a little bit of background about cadexomer iodine and how it works? 00:00:15


Absolutely, Ruth. Thank you so much for having me. Cadexomer Iodine consists of biodegradable spherical hydrophilic beads of Cadexomer Starch. Inside the starch, it incorporates about 0.9% of Iodine. It is available in powder, gel*, ointment, a  type of dressing format. The beads are actually very absorbent. In contact with wound and exudate, it can absorb up to seven times of their own weight in fluid that can lead to the physical swelling of the beads and further removal of slough, pus, debris and even bacteria into the dressing. The physical swelling of the Cadexomer beads upon contact with fluid allows the sustained availability of Iodine, which kills bacteria and biofilm within the dressing for up to 72 hours.(1) 00:01:03

This mode of action is reflected in clinical use by the removal of barriers to healing such as exudate, slough , bioburden and biofilm from the wound. Creating a perfect environment for wound healing to progress. More recently, we also understand a lot more of why this product is so effective against biofilms. Again, this is related to the physical action of the beads disrupting the biofilm matrix followed by Iodine, which kills biofilm bacteria rapidly.(1) 00:01:58


OK, thanks for explaining that. And perhaps tell me, why was it important to do this analysis? 00:02:32


Interesting question, I think there are many different studies around the globe. In fact, there are 40 years of successful clinical use around the globe with cadexomer iodine. And we have collected a huge volume of clinical data and high-level evidence demonstrating the clinical outcomes and benefits of using IODOSORB in sloughy, infected chronic wounds. However, people are not always aware of the extent and quality of this evidence. So we wanted to summarise this in one place to remind clinicians how effective this product is as part of infection management and wound bed preparation in chronic wounds. Cadexomer Iodine already have a positive statement in the 2010 and 2014 Cochrane review into antiseptics and antibiotics for treatment of venous leg ulcers(1).Highlighting the faster rate of healing in these wounds compared to standard of care. In addition, as much of the data is from high-level studies across different chronic wounds like randomised controlled trials, we can bring this data together and do further analysis to provide an even stronger dataset to show clinicians and support evidence-based clinical practice for pathways and protocols across all Chronic wound  types.(1) 00:02:39


OK, thank you. And perhaps, Ben, perhaps you could just explain a little bit what's the difference between a systematic literature review and a meta-analysis? 00:04:01


Yeah, sure. So, that's a really good question. So, what I'll do first is just explain what a systematic literature review is. And I guess the formal definition of a systematic literature review is any review that uses repeatable analytical methods to collect and summarise current evidence relevant to a predefined research question. And these types of reviews use sort of specific search terms and inclusion-exclusion criteria that are stated upfront in the method section of the review. Whereas, in contrast, a normal literature review will not tend to provide this information. And so the general aim of a systematic literature review is to give a balanced view of the available evidence, which, again, is different to a traditional review, which tends to use what we tend to call sort of ‘cherry picked’ studies that are aimed at highlighting what is the most important to the topic of interest being studied. A systematic review will characterise the quantity and quality of the literature, which is generally something a normal literature review won't do is that quantification aspect. And this includes evaluating study design and other features, such as outcomes and endpoints used in the literature identified. So, systematic reviews should typically follow some type of guidance around reporting standards. And the one that we actually used in our paper is the preferred reporting items for systematic reviews and meta-analysis, which is shorthand. And shorthand, that is Prisma. And these are strict guidelines that ensure the input into the study is fair, representative and unbiased, and therefore the output from the study is more likely to be scientifically robust. On the other hand, we've got this is also, the study is a meta-analysis, and that is very different to a systematic literature review. And that is basically a form of statistical analysis that combines the results of more than one quantitative study. A meta-analysis is performed when there are multiple scientific studies, usually randomised controlled trials, but sometimes other studies are included. And they all, all those studies address the same research question. So, for example, a meta-analysis looking to determine the benefit of using a new drug that's designed to reduce heart attacks will compare that to the standard of care, will include individual studies that basically answer that same research question. That is to evaluate the drug compared to standard of care for preventing heart attacks. So the premise behind a meta-analysis or the reason why we perform them is because an individual study on its own reports that results are expected to have some degree of error or be confounded by individual various factors or biases. We used statistics, in other words, in better analysis to derive a pooled estimate closest to the unknown common truth based on how this error is perceived. Much like a population average, while simultaneously better accounting for individual study flaws. You might typically see the results of a better analysis reported as a forest plot. And that shows the results graphically, but will also report the overall individual treatment effects.(3) 00:04:13


OK. And so perhaps you could talk me through how you went about doing this systematic literature review and meta-analysis for all this data for Cadexomer Iodine. 00:07:35


Yeah, sure. So like I said, we performed this systematic literature review according to the Prisma guidelines mentioned earlier, which means the methodology of our review is very similar to many other studies following those guidelines. And so this includes outlined and in detail within the manuscript's what search terms were used, the overall strategy and information sources used, for example. And so hopefully the end result is when you follow these Prisma guidelines, is you have a high-quality review that attempts to present the identified data impartially. Now, just going briefly on to the details of the study design, the search terms that we used were directed at capturing all the data on IODOSORB included in its different presentations like ointment, dressing and the regional market names like IODOFLEX, which IODOSORB dressing is known as in the United States. It's also worth noting that we use the generic name for IODOSORB in the search terms, which is Cadexomer Iodine. And usually, when you use a generic name for a drug or a device, you don't actually know if it's actually your device the study's referring to but because IODOSORB is the only Cadexomer Iodine product on the market, this wasn't such a problem. We used no lower date limit for collecting data from electronic databases as we want to capture some of the older studies that investigated IODOSORB. It's a product that's been around for quite a long time, but that's largely due to how clinically effective the product is. So it stood the test of time. We also used a technique that's typically known as ‘Snowballing’, and which is where you find additional articles for review by looking at the reference lists other studies identified in the main systematic search. And that bolsters the amount of studies that you can sort of find from your review. Looking at the inclusion criteria we used involved looking at only comparative studies. So that's any study that, you know, that didn't include, didn't compare IODOSORB to standard of care that those sort of studies were excluded. So it's only those studies that were comparative. Importantly, we wanted to look at a set of key outcomes of interest. And these were clinically relevant endpoints, such as wound healing parameters, like total reduction in wound area and complete wound closure. So, many of the comparative studies identified from the systematic review, reported at least one of these measures of interest, outcome measures of interest. So this was not a common reason for exclusion among identified studies. As part of the Prisma standards, you are required to perform and declare bias assessments of the studies, included in review, and you can actually see that in the supplementary material of the published manuscripts. And what these bias assessments are essentially designed to do is allow the reader or you as the reader to determine how many studies were at risk of bias and the necessary caveats that we placed on the findings of any study, of any study that would be if those studies were high, of high risk of bias. And one of the most important aspects of the statistical analysis we performed in this study was accounted for statistical heterogeneity. So for those who don't know what heterogeneity is, put simply heterogeneity is essentially variation in some way or unique differences between an entity or constructs such as clinical studies. And there's basically three types of heterogeneity that we're interested in for research. And that's statistical, clinical and methodological heterogeneity. So it's important to account for these when performing aggregate analyses like a meta-analysis as having high heterogeneity can add limitations to the findings. So, statistical heterogeneity actually has a link to both clinical heterogeneity and methodological heterogeneity as the higher levels of these two variables sort of affects the variation in treatment effect sizes for a given outcome. So examples of clinical heterogeneity factors might include sort of individual differences between studies such as the types of patient populations included or the different wound types from each study. While methodological heterogeneity might be things like differences in measurement tools, use between each study and all of these factors can up to affect statistical heterogeneity. And importantly, we account for that statistical heterogeneity by using more stringent statistical models when there's higher levels of statistical heterogeneity. So we do account for that in the study. And then finally, for those studies, we didn't include in the meta-analysis for some reason, like missing standard deviations or improper reporting, we qualitatively analysed that data. It's still important to identify possible trends and improved outcomes within the clinical data.(1) 00:07:47


OK, so what were the key findings when you pulled all of this really great, you know, all RCT level data for IODOSORB? 00:13:03


Yeah. So actually, there are some pretty big key findings from this study. So like I said, we managed to perform meta-analysis for a number of key wound healing outcomes, comparing IODOSORB to standard of care. And these outcomes included reduction in ulcer purulence and debris, reduction in pain, reduction in wound area and most importantly, the incidence of complete wound healing. So, looking at specifically for some of these results, for the reduction in ulcer pain outcome, IODOSORB reduced pain reported by patients by nearly 15 points on average, more on the visual analogue scale than compared to standard care after a time period of six to eight weeks. And this finding was statistically significant. There was also statistically significant improvement in the reduction of ulcer area associated with the use of IODOSORB compared standard care. With chronic wounds, healing on average, greater than two centimetres more than the standard of care after eight weeks of therapy. And then finally, in a meta-analysis of wound healing data from eight studies, we were able to demonstrate wounds were greater than two times more likely to heal with IODOSORB treatment compared to standard of care. And this is also a statistical significant finding. And then for those studies and outcomes that weren't amiable to being included in a meta-analysis. And so were qualitatively analysed IODOSORB was found to significantly reduce many of the barriers to wound healing, including excess exudate slough, bioburden across multiple high-level studies compared to standard of care. So, what we're potentially seeing is that improvement in these surrogate wound healing markers with IODOSORB is all is reflected in the significantly higher rates of complete wound closure. So basically by using IODOSORB you're reducing slough, purulence and wound debris and reducing the overall bioburden in the wound, which then puts the wound back on track for a complete wound healing trajectory, which is the ultimate clinical goal for any wound.(1) 00:13:12


Yeah, that's some really key findings there from that study, isn't it? So, Kevin, you know, you deal with chronic stalled wounds on a daily, daily basis in your practice. So, how does this data in this study translate to what you see in your clinic? 00:15:26


Good question, Ruth. I think, as you are aware, chronic wounds are very common, whether we're talking about pressure injuries, venous leg ulcer or diabetic foot ulcers. We see we're seeing actually more and more people suffering from those wounds because of the growing number of people suffering from diabetes and other chronic conditions. And the change in lifestyle with more obesity in the population. So we're dealing with chronic wounds from time to time. And one of the biggest challenge, in addition to addressing the underlying aetiology, is to manage the bioburden, as Ben had mentioned earlier. And one of the parts we're nowadays in the literature is the biofilm problem in chronic wounds. As you have, as we may be aware, biofilm is basically ubiquitous in chronic wounds. I think in the literature they talk about more than 80% of chronic wounds have biofilm problem (4).The issue with biofilm is it perpetuates this inflammatory response and also a number of the physiological changes that result in this stalled non-healing, difficult to heal situation. So by addressing the biofilm more appropriately, we can definitely facilitate the healing process. As you can imagine, with the number of chronic wounds that put an immense amount of pressure and the burden on health care system, and not to mention about human suffering as well. So I think what we have seen in clinical practice with the use of IODOSORB we're able to manage the local bioburden and the biofilm problem more effectively. And it's been mentioned in the meta-analysis, I'm actually quite impressed by the results indicating that IODOSORB is more effective to manage pain and removing slough and debris. And that's exactly what we have seen in clinical practice. In many situations where we have stalled wounds, we assume that there is a biofilm problem. We applied Iodosorb whether it's powder or ointment depends on the volume of exudate. We were able to remove and effectively disrupt the biofilm and that can result in more effective and better healing process. And along with it, as Ben mentioned too, the surrogate, the proxy indicator telling us that potentially it's a biofilm problem. We when we looked at the literature, we identified pain is one of the key indicator for biofilm problem, perhaps because of the presence of bacteria, because of the inflammatory response triggering a lot of those pain receptors along with it, the high volume of exudate, smell, slough, friable tissue on the wound bath suggesting there may be a biofilm or covert infection issue. So, definitely, we have seen the, in my clinical practice, we use the Cadexomer Iodine to deslough, to clean off the debris, to clean of the biofilm and to facilitate healing process. 00:15:48


And so what type of wounds do you use IODOSORB on and why and maybe you can talk us through some of your successes that you've had with some cases. 00:18:59


Oh, absolutely. I think in my practice I use IODOSORB not based on the wound type, and definitely can be used on many different wound types, like pressure injuries, venous leg ulcers or diabetic foot ulcers. But often I apply this type of agent based on the presence of biofilm and where wounds are not healing I always presume there is a bioburden issue that needs to be addressed. Of course, after addressing all of the underlying aetiology at the same time and looking at a holistic, comprehensive patient assessment. So recently, I was doing a few case studies using IODOSORB just to showcase what this product can do on chronic stalled wounds. And I came up with some really interesting cases. One case that's sort of a I can recall right now is a patient with a pressure injury on the trochanteric area. He had this wound for a long time. He was treated with bone infection, what we call it osteomyelitis. He developed this wound in the intensive care unit. He was not a very healthy person with advanced stage of renal disease on dialysis, diabetes and other cardiovascular conditions at the same time. So, in other words, this person is very frail and have a lot of comorbidities that can compromise his condition and the ability for him to promote better healing. And no surprise there, when I look at the wound, basically it has not been progressing for a number of weeks now. And people continue to use the same dressings. So, what my immediate reaction was, well, this is not effective clearly, so we need to switch to something that is more evidence-based and able to address the biofilm problem in the wound bed. So we applied the IODOSORB ointment and because of the exudate we had to switch from the ointment to powder because each granule, it's so absorbent, able to take in a lot and wick away a lot of exudate. And in addition to that, we covered the area with a ALLEVYN foam dressing to provide some cushioning and protection to the area. And we're able to see that within a couple of weeks. And usually, the rule of thumb is to make sure we have this two-week challenge to ensure we apply the agent or the treatment for at least two weeks and continue to monitor observe the response from the wound to do, to determine the effectiveness of the treatment. So we follow through the two-week challenge and we're able to see significant improvement of the wound size, wound surface reduction. Reduction in terms of the and improve quality of the wound tissue. There's more granulation tissue, less friable, less debris and slough on wound bed and not to mention about the reduction in the exudate. And in the end, we're able to reduce the dressing frequency from daily to about three times a week. So you can imagine the cost-effectiveness of this intervention, we're saving a lot of nursing time, we're saving the dressing products, and not to mention about the improvement in quality of life for this individual. And I think eventually we're able to close this wound. It took us a little bit more time, but we're able to completely close this one up. And this patient was able to discharge from the hospital and we turned back to a long term care facility. 00:19:10


That's really great to hear those positive outcomes for the patient especially, isn't it? So perhaps, finally, you can tell us a little bit about how this data is being used to support the infection management pathway you were a part of developing, Kevin. 00:23:00


Oh, absolutely. With pleasure. I'm so fortunate to be part of this expert panel to develop this pathway. We collectively reviewed all the clinical guidelines, documents available to us, including some of the high-level clinical evidence and opinion papers. I think it's sort of the conclusion very similar to one of these surveys that was done recently, including more than 300 health care providers across the world, indicating that we need to have something better to guide clinical decision-making process. And that's the impetus for us to create this pathway so we can facilitate the scaling up of this intervention to integrate that into a routine practice. And we basically summarising all the key indicators and signs and symptoms associated with different types of wound infection.(2) Wound infection has been described by the International Wound Infection Institute as a continuum from colonisation, contamination, colonisation to local infection and then spreading systemic infection(5). So I think it's important to be able to promptly and be able to arrive at early diagnosis of wound infection, whether it is a local infection or spreading systemic infection because by recognising there is an infection problem, we can apply interventions earlier to address that bioburden. And that's part of what the pathways is all about, listing and identifying all the common signs and symptoms discussed in the literature. So we separated wound infection. On one side we have the Covert biofilm-related infection problem. Some of the signs we've talked about, including pain, exudate, smell, slough and friable tissue. On the other side of the pathway, we have signs and symptoms listed for overt infection, for deeper infection, including increased temperature, oedema, erythema and other problems. So and then following this pathway, then we identify, based on the literature and evidence available to us, that IODOSORB cadexamer iodine   is more effective against covert biofilm problem where as silver is used primarily for a spreading infection or systemic infection, especially where antibiotics are being prescribed. So by using this pathway, it really is standardising the way that we think, the way that we apply different interventions and the more effective intervention based on the presentation of wound and the type of wound infection problem. So at the end, hopefully, we're able to and we've seen that we're able to arrive at better outcomes and cost-effectiveness in our care. So I think this has been a very interesting journey to look at applying evidence, creating this pathway. Looking at some of the actionable items, and to disseminate this and use that in clinical practice. And in my day to day interaction with nursing staff and some of the clinicians and they found this pathway is so straightforward, so intuitive and so easy to use and definitely provide some concrete suggestions and ideas for them to assess the wounds for infection, apply the right treatment for the right type of wound, and the right type patient. So we keep emphasising that we have to get everything right for wound treatment. And that's part of the fun of it. 00:23:16


Yes. And we're going to have the infection management pathway (2) attached to this podcast. So, do check out the resources attached to the podcast and you can see the pathway there. So, you know, thanks for your information there that you've given us, Kevin and perhaps just as a last word or, you know, key takeaway message. Ben, would you like to just give the audience something to take away from today? 00:27:20


Yeah, absolutely. So I think most importantly, go read the paper. But secondly, I mean, this is, you know, key clinical evidence. This is evidence-based medicine. The study is a highly, you know, robust, systematic literature review. So this sort of, you know, puts a basis behind what's been seen in the clinic, as Kevin's gone through and again, you know, it's quite clear from the data that we've, you know, we found from this study that there's, you know, a real benefit to using IODOSORB for management of chronic wounds. And I guess, you know, is more important now than ever, because, you know, with increasing antimicrobial resistance, that clinicians have another tool in their armamentarium to combat, you know, infections without having, you know, to worry about selecting the right tool for the job. And I mean, this is, you know, more important now that we have these tools, we can combat the problems of infection, but also simultaneously promote greater wound healing. 00:27:52


Thank you. And perhaps, Kevin, do you have a takeaway message for today? 00:29:09


Sure. I think read the paper, of course, like Ben had said, and I think also used the pathway. We love to hear clinicians about the utility and feasibility of using this pathway in clinical practice. Ultimately, we want to continue with our endeavour to revise, to update, to make this more user-friendly for clinicians at the bedside, particularly. So we hopefully following this pathway with the new evidence emerging on a day to day basis, we're able to provide better guidance and better information for you to integrate into practice from time to time. And again, the key message at the moment is we know that Iodine product is more effective against biofilm. We know biofilm is extremely common in chronic wounds. And that's part of the reason why wounds are not healing. So, in other words, we need to be more vigilant. We need to be more I wouldn't say liberal, but I think we need to be more open to the idea of using antimicrobial agents like Iodine Cadexomer for the treatment of chronic wounds in order to address all the key issues and barriers for wound healing. 00:29:15


Yeah. Thank you. And we really appreciate your time. So, thank you to Kevin and Ben for joining us today and to our audience and don't forget to tune in to our next podcast and we'll see you soon. Thanks and bye for now. 00:30:29


Thanks, Ruth. Thanks, Ben. 00:30:43


Thank you. 00:30:45

SPEAKER: 00:30:46

Meet the challenge of biofilm. Antibiotics are ineffective against biofilm, and misuse can lead to resistance. Disrupt biofilms with IODOSORB. Up to three days of Iodine release (1) For more information, contact your local Smith and Nephew representative. Or email us at ProfEd.ANZ@smith-nephew.com. The information presented in this podcast is for educational purposes only. It is not intended to serve as medical advice. Products listed out the line of care are examples only. Product selection and management should always be based on comprehensive clinical assessment. The detailed products information include indications for use, contraindications, precautions and warnings. Please consult the products applicable instructions for use prior to use. Helping you get close to zero wound biofilm.


1. Woo, K. et al. Efficacy of topical cadexomer iodine treatment in chronic wounds : Systematic review and meta-analysis of comparative clinical trials. Int. Wound J. e-pub, 1–12 (2021).

2. Dowsett, C., Bellingeri, A., Carville, K., Garten, A. & Woo, K. A route to more effective infection management: The Infection Management Pathway. Wounds Int. 11, 50–57 (2020).

3. Page MJ, McKenzie JE, Bossuyt PM, Boutron I, Hoffmann TC, Mulrow CD, et al. The PRISMA 2020 statement: an updated guideline for reporting systematic reviews. BMJ 2021;372:n71.

4.     Malone M, et al. The prevalence of biofilms in chronic wounds: a systematic review and meta-analysis of published data. J. Wound Care 26, 20–25 (2017

5.     International Wound Infection Institute (IWII) Wound infection in clinical practice. Wounds

         International 2016

*Please note. IODOSORB 0.9% Cadexomer Iodine Gel is not available in Australia or New Zealand.

Supplementary tools to podcast

• Woo 20211 Meta-analysis paper and link to IWJ https://onlinelibrary.wiley.com/doi/10.1111/iwj.13560

• Dowsett et al 2020 Infection management pathway2 https://www.woundsinternational.com/journals/issue/624/article-details/route-more-effective-infection-management-infection-management-pathway

. O’Meara S et al. Cochrane Database Syst Rev 2014;

Jan 10; (1): CD003557

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Dr. Kevin Woo

RN, BScN, MSc, PhD

Associate Professor,

School of Nursing,

School of Rehabilitation Therapy,

Queen's University,

Kingston ON Canada

Advanced Wound Consultant,

West Park Health Center, Toronto, Ontario

Kevin Woo is an Associate Professor at Queen’s University, School of Nursing, School of Rehabilitation therapy in Kingston, Ontario. He teaches and provides supervision for both undergraduate and graduate students in the Healthcare Quality program, Aging and Health program, as well as the Nursing Science programs.  Kevin is an adjunct research professor at the Western University teaching for their Masters of Clinical Science in Wound Healing program.

He is recognized as a national expert in wound care and has served on a number of expert panels and advisory boards to develop the Best Practice recommendations. He received the Journal of Wound Care Best Diabetic Foot Ulcer Intervention Award in 2018 for his contribution to advance diabetic foot care and Journal of Wound Care Professional Education Award in 2017.  He is the Regional Director – North America of the International Skin Tear Advisory Panel (ISTAP).  He is a member of the Education Committee of the Canadian Frailty Network.

A recipient of the Early Researcher Award from the Ministry of Research and Innovation (2014-19) and the International Association for the Study of Pain Early Career Research Award (2012-13), Kevin has a range of research interests, including enhancing chronic disease self-management, developing quality benchmarks for wound management, and implementing best practices for difficult-to-heal wounds. He has authored or co-authored over 130 peer-reviewed publications, books, book chapters, white papers and proceedings. Kevin maintains his clinical expertise and functions as an Advanced Wound Consultant at the West Park Health Care Center, a specialized chronic care and rehabilitation hospital in Toronto.

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Ben Costa

Clinical Evidence Specialist

Clinical Affairs

Smith+Nephew UK

Ben Costa first joined Smith and Nephew in 2018. He has an academic background in Biomedical Science and Clinical Microbiology, with interests in Computer Science and Data Analytics. Prior to joining Smith and Nephew, he worked as a contractor writing Clinical Evaluation Reports to support regulatory requirements for wound care products. In his current position as a Clinical Evidence Specialist in the Evidence Analysis team, his role is to utilise clinical evidence to derive commercial and strategic value to the business through conducting activities such as systematic literature reviews and meta-analyses.

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