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Standardising the methodology of research into chronic wounds

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Jacqui Fletcher, BSc (Hons), RN.

Senior Lecturer, University of Hertfordshire, Hatfield

The practicalities of monitoring the frequency of chronic wounds were discussed last month (Fletcher, 2003). The aim of this paper is to consider some of the published data currently available and to identify key issues related to this information.
The practicalities of monitoring the frequency of chronic wounds were discussed last month (Fletcher, 2003). The aim of this paper is to consider some of the published data currently available and to identify key issues related to this information.

Individual studies of frequency will not be critiqued and compared because this has already been covered extensively within the published literature. Examples of published review data include:

- Pressure ulcers: Kaltenthaler et al (2001); Thoroddsen (1999)

- Leg ulceration: Fletcher (1996)

- Diabetic foot ulcers: Hutchinson et al (2000).

There is little if any data on the frequency of fungating wounds and figures that do exist acknowledge that their true frequency is difficult to determine as many patients delay in presentation for a variety of reasons (Fairbairn, 1993; Grocott, 1993).

It is clear from all the data reviewed that there is inconsistency in the suggested frequency of occurrence of many chronic wounds. Many of these differences can be simply explained by differences in methodology as discussed in the first part of this paper; however, other issues warrant further discussion.

Correct use of terminology
Definitions of prevalence and incidence are given in Box 1.

In some instances terminology appears to be used incorrectly. For example, several papers describe retrospective documentation reviews, counting all episodes of active ulceration with no attempt to separate out those patients who were disease free at the beginning, under the title of incidence surveys. This would appear to more closely relate to prevalence (either point or period). However, the methodology sections are often brief, with inadequate detail provided, so that it is unclear if an incorrect term has been used or if the reader does not fully appreciate the method because it is not clearly described.

One other area of confusion is the inclusion in some papers of a definition that encompasses both open and healed wounds. This does not appear to closely match what is required of either prevalence or incidence. One possible explanation may be that some wounds have a high recurrence rate and it is very likely that they will break down again, therefore the study is identifying the potential as well as the actual burden of managing the patients. However, this appears to be very random as there is probably an equally high chance of patients who have never presented with the disease occurring.

It is perhaps also worth considering that a standard dictionary definition of incidence differs from the scientific definition, being simply the 'frequency with which something happens' (Chambers, 2003). If this definition is used it would encompass both prevalence and incidence and nullify the argument about using the term incorrectly. It is not suggested that this should be the case, this is simply put forward as an explanation of why there may be confusion relating to the correct usage of the terms.

Differences in presentation
In most chronic wound literature frequency figures are presented as a percentage occurrence rate. For example, a prevalence rate may be 27%; however, the leg ulcer studies tend to present their data as ratios - a number out of the population. So they would appear as 178:200 000 (Rotchell, 1999), which equates to 0.89%. While this is an interesting observation it actually makes little difference. However, for those who find maths challenging it is simply another hurdle to leap in interpreting and comparing figures. On a positive point, however, it emphasises the size (which is in this case comparatively large) of the total population surveyed and this may not be clear where percentages alone are presented.

Why were the data collected?
It would appear that collecting frequency data on chronic wounds occurs for a variety of reasons and the reason will impact on what is collected and how it is used. Broadly speaking the main reasons appear to be:

- A genuine desire to know the frequency

- A need to understand what is behind the frequency

- A need to know the frequency in relation to need for service development/expansion (or closure/reduction)

- To identify by further data analysis 'at-risk' groups

- To identify by further data analysis areas for educational input (staff or patients)

- To justify or rationalise resource allocation.

With the exception of the first reason all the others require the collection of additional data. This is the factor which most frequently complicates the data collection process, as many succumb to the 'may as well collect while we're there' impulse and collect a considerable amount of extraneous data. This makes data handling and analysis complex and may mean essential data is overlooked or not thoroughly collected. It is important therefore that a clear objective is set before beginning data collection.

For example, if the objective is to determine which patients are at increased risk of diabetic foot ulceration so that services or education may be appropriately targeted, then it is reasonable to collect data such as presence or absence of neuropathy or ischaemic disease, which it is believed contribute to that risk, in addition to the actual frequency data.

Similarly, a frequency study may be used to demonstrate both a clinical outcome and a process outcome. For example, studies of the prevalence of pressure ulcers will usually collect information on the patients' level of risk and also the type of equipment being used. This allows both the measurement of the frequency of pressure ulceration and, additionally, identification of whether appropriate care is being given. This identifies both the outcome and, potentially, whether it is something within the process of care that results in that outcome.

It must also be considered that there are limits to what it is possible to achieve when using data as a comparative measure to identify a positive impact related to guideline implementation. Even when care is 'gold standard' and based on the best available evidence the frequency of occurrence may not fall below a given level. This is clearly illustrated in a Japanese study (Hagisawa and Barbenel, 1999) on the frequency of pressure ulcers following an extensive teaching programme and guideline implementation.

Many prevalence and incidence figures quoted for all chronic wound types refer back to classic studies carried out in the 1970s and 1980s. While these studies may in themselves be very robust, their relevance to the current population and health-care delivery system must be considered. This will mean that due consideration must be given to case-mix adjustment as health-care delivery patterns and the demographic mix within the population changes.

Those carrying out frequency studies should be aware of the complexity of the task, and the burden data collection imposes. Where appropriately skilled personnel are not available to design, implement and analyse frequency studies, serious consideration should be given to the usefulness of carrying them out. While much interesting data can be collected its usefulness may be limited and the resource burden be unreasonable for the potential benefit. Where they are available standard data collection tools should be used. Many clinicians have devoted hours of time and effort to producing forms when standard data collection tools exist, in the belief that their area is 'special' or is in some way different or that locally developed tools are viewed more positively. There is no doubt that adaptation may be required for some tools; however, it requires considerably fewer resources to adopt and adapt an existing tool than it does to create from new. Where tools have been previously validated it adds to the robustness of the data collected.

Using standard data collection tools is not an impossibility. Bours et al (1999) specifically commented on the use of common tools across a range of health-care settings and the possibility of using this approach was clearly demonstrated by the Clark et al (2002) study, which collected data both across different health-care settings and different countries. In the USA minimum data sets are available and widely used for reporting a range of conditions. The use of a minimum data set does not preclude additional information being collected. However, the objective of the data collection and the practicality and implications of gathering large quantities of data should be borne in mind.

Presenting and publishing data
As a starting point it is suggested that both authors and journal editors (including reviewers) ensure that adequate definition is given of:

- The objectives of the study

- The disease being studied (does 'leg ulcer' include or exclude pressure ulcers and diabetic foot ulcers?)

- The total population and reason for selection of that population

- The survey methodology and response rate and that both crude headline data and data with interpretation are presented.

Tools used should be presented and their shortcomings discussed, as should methods of ensuring reliability of the data. Clinicians and their professional bodies need to work together to standardise specific terminology that may be utilised in the studies.

Generally a more critical approach should be taken to the analysis and use of the data that are generated. Only when this level of standardisation is insisted on and adhered to will data be able to be used comparatively with reasonable ease. Currently although there is, as previously stated, a wealth of data, its use is fraught with difficulty because of the many complicating factors and its usefulness to many clinicians is limited because of the incompleteness and inaccuracies within the information.

Box 2 provides tips for nurses conducting research into the frequency of chronic wounds.

In order to improve the quality and comparability of the published frequency literature it is strongly suggested that both the reporting and interpretation of prevalence and incidence data be subject to standardisation. This would be in the same way that the CONSORT statement lays out guidance for what minimum data should be published relating to the conduct of randomised controlled trials (Begg et al, 1996) or in the way that the AGREE Collaboration critiquing tool (AGREE Collaboration, 2003) allows critique of published guidelines.

The European Pressure Ulcer Advisory Panel has made the first steps towards achieving this in the area of pressure ulceration with the publication of a minimum common data set outlining both tools to be used to assess risk and grade damage and the minimum information to be collected (EPUAP, 2000). This tool has been successfully piloted in a pan-European prevalence survey in November 2001 (Clark et al, 2002). EPUAP has also produced a draft statement on prevalence and incidence monitoring (Defloor et al, 2002). This draft statement will be developed to include guidance for publication and review of prevalence and incidence studies and it is hoped that this will be available by the end of this year.

Although these two pieces of work relate specifically to some of the problems encountered when counting pressure ulcers it is likely that the underlying principles could be adapted to other wound types.

AGREE Collaboration. (2001) AGREE Instrument. Available at: Accessed March 2003.

Baumgarten, M. (1998) Designing prevalence and incidence studies. Advances in Wound Care 11: 6, 287-293.

Begg, C., Cho, M., Eastwood, S. et al. (1996) Improving the quality of reporting of randomized controlled trials: the CONSORT statement. Journal of the American Medical Association 276: 8, 637-639.

Bours, G.J.J.W., Halfens, R.J.G., Lubbers, M., Haalboom, J.R.E. (1999) The development of a national registration form to measure the prevalence of pressure ulcers in the Netherlands. Ostomy/Wound Management 45: 11, 28-40.

Chambers. (2003) Chambers Dictionary. London: Harrop Ltd.

Clark, M., Bours, G., Defloor, T. (2002) Summary report on the prevalence of pressure ulcers. EPUAP Review 4: 2, 49-57.

Defloor, T., Bours, G., Schoonhoven, L., Clark, M. (2002) Draft EPUAP statement on prevalence and incidence monitoring. EPUAP Review 4: 1, 13-15.

European Pressure Ulcer Advisory Panel (EPUAP). (2000) Developing a minimum common data set to record the prevalence of pressure ulcers in European hospitals. EPUAP Review 2: 3, 75-77.

Fairbairn, K. (1993) Towards better care for women: understanding fungating breast lesions. Professional Nurse 9: 3, 204-212.

Fletcher, A. (1996) The epidemiology of leg ulcers. In: Cullum, N., Roe, B. (eds). Leg Ulcers Nursing Management: A research-based guide. London: Bailliere Tindall.

Fletcher, J. (2003) Measuring prevalence and incidence of chronic wounds. Professional Nurse 18: 7, 384-388.

Grocott, P. (1993) Fungating malignant wounds I: an overview and priorities for palliative management. Wound Management 4: 2, S2-S3.

Hagisawa, S., Barbenel, J. (1999) The limits of pressure sore prevention. Journal of the Royal Society of Medicine 92: 576-578.

Hutchinson, A., McIntosh, A., Feder, G. et al. (2000) Clinical Guidelines and Evidence Review for Type 2 Diabetes: Prevention and management of foot problems. London: Royal College of General Practitioners.

Kaltenthaler, E., Whitfield, M.D., Walters, S.J. et al. (2001) UK, USA and Canada: how do their pressure ulcer prevalence and incidence data compare? Journal of Wound Care 10: 1, 530-535.

Rotchell, L. (1999) Introducing and auditing a nurse-led leg ulcer service. Professional Nurse 14: 8, 545-550.

Thoroddsen, A. (1999) Pressure sore prevalence: a national survey. Journal of Clinical Nursing 8: 170-179.
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