Background
A chronic wound can be defined as one that has failed to proceed through an orderly and timely reparative process to produce anatomic and functional integrity within a period of 3 months or that has proceeded through the repair process without establishing a sustained, anatomic and functional result [
1,
2]. The nomenclature is far from agreed upon, and these wounds are sometimes referred to as hard-to-heal or difficult-to-heal wounds/ulcers, and the time span required for chronicity has been defined in the range 4 weeks up to more than 3 months [
2‐
4]. Based on the causative aetiologies, the Wound Healing Society classifies chronic wounds into four categories: pressure ulcers, diabetic ulcers, venous ulcers and arterial insufficiency ulcers [
5]. Chronic wounds are often termed ulcers and can be defined as wounds with a full thickness in depth and a slow healing tendency. Often disguised as a comorbid condition, chronic wounds represent a silent epidemic that affects a large fraction of the world population [
6]. It is estimated that 1 to 2 % of the population will experience a chronic wound during their lifetime in developed countries [
7]. The dramatic increase in the ageing population will increase these numbers as wound closure is negatively associated with age [
8]. Complications of chronic wounds include infection such as cellulitis and infective venous eczema, gangrene, haemorrhage and lower-extremity amputations. Chronic wounds lead to disability and disability worsens wound outcomes resulting in a vicious cycle [
9].
Due to the low base rate of complete healing in the natural history [
10], chronic wounds have a significant impact on the health and quality of life of patients and their families, causing pain, loss of function and mobility, depression, distress and anxiety, embarrassment and social isolation, financial burden, prolonged hospital stays and chronic morbidity or even death [
11]. Evidence suggests that chronic wounds impose significant and often underappreciated burden to the individual, the healthcare system and the society as a whole [
12,
13]. In the USA, for example, chronic wounds are reported to affect 6.5 million patients with more than US$25 billion each year spent by the healthcare system on treating wound-related complications [
6]. The costly nature of chronic wound management is further confirmed with estimates from the UK, where the cost to the National Health Service of caring for patients with chronic wounds were conservatively estimated at US$3.4–4.6 billion per year (in 2005) representing around 3 % of the total estimated out-turn expenditure on health for the same period [
14].
Preliminary literature search suggests that there are at present no reliable estimates on the total prevalence and incidence of chronic wounds for different settings and categories of chronic wounds [
15]. The wide disparity of the epidemiological estimates arises mainly from significant heterogeneity in terms of study design and data collection method [
15]. The varieties also come from the way of reporting prevalence: some report point prevalence while others report period prevalence [
15]. The same disparity is also found in incidence reports. We aim to embrace a larger number of databases and a considerable broader search strategy compared to a previous review [
15]. We also intend to thoroughly assess and consider the quality of included studies and carefully pay regard to the applied definitions of chronic wounds. These approaches are believed to provide more reliable estimates on the prevalence for different settings and categories of chronic wounds than previously presented. Such information is essential for policy and planning purposes particularly as the increasing number of elderly and the increase in the prevalence of lifestyle diseases further raise the risk for chronic wounds. The literature review is intended to gather the existing knowledge and identify factors of importance to the prevalence of chronic wounds and to the incidence of complications. The focus is on chronic wounds in the categories of pressure ulcers, diabetic ulcers, venous ulcers and arterial insufficiency ulcers.
Specific review questions are:
-
What is the prevalence and incidence of chronic wounds in the categories of pressure ulcers, diabetic ulcers, venous ulcers and arterial insufficiency ulcers, for different settings and subgroups according to internationally published studies?
-
What is the prevalence and incidence of infections, gangrene, haemorrhage and limb amputation among patients with chronic wounds in the categories of pressure ulcers, diabetic ulcers, venous ulcers and arterial insufficiency ulcers, for different settings and subgroups according to internationally published studies?
Further knowledge about the distribution of chronic wounds and related complications in different settings and among subgroups is essential for informing healthcare planning and resource allocation. Pooling of such data is also necessary to monitor trends in disease burden and to contribute to the design of further etiological studies.
Objectives
The overall aim of this systematic review protocol is to present a transparent process for how the information will be collected on the prevalence and incidence of chronic wounds and related complications. This will include the key research questions that this systematic review will address, a description of systematic literature search strategies, criteria for inclusion or exclusion of studies, a description of coding procedures, study quality measures and statistical procedures for the quantitative analysis of data from eligible studies.
Summary
This systematic review and eventually meta-analysis will be performed to critically examine the world’s relevant literature on the epidemiology of chronic wounds. Specifically, we aim to identify and report the estimated prevalence and incidence of chronic wounds in the categories of pressure ulcers, diabetic ulcers, venous ulcers and arterial insufficiency ulcers and related complications for different settings and subgroups. We will also identify population characteristics associated with chronic wounds in the four categories and with the following complications: infections, gangrene, haemorrhage and limb amputation. Understanding the rates of different categories of complications among patients with chronic wounds could help target patient subgroups that may benefit from early screening, prevention, and treatment efforts. In addition, quantifying the magnitude of chronic wounds will help guide decision-making for the allocation of scarce healthcare resources and funding. A further finding of this systematic review will be the result of the methodological assessment of the published literature. The findings of this review will also be compared with other similar published reviews. Finally, conclusions will be drawn from this systematic review highlighting the prevalence and incidence of chronic wounds, methods of estimation and settings and their correlates. Limitations of the studies will be discussed in detail. Implications of the review as well as suggestions for future research will also be provided.
Acknowledgements
We are grateful to Carl Gornitzki at the university library at the Karolinska Institutet, Sweden, for invaluable support in the refinement of the search strategies.
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