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Larval therapy: a case for inclusion in the Drug Tariff

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VOL: 98, ISSUE: 36, PAGE NO: 48

Dilys Millard, BSc, RGN, RM, DN(DipHE), is a nurse adviser, NHS Direct West Country, Taunton, Somerset

The Drug Tariff sets out the rules as to which drugs and appliances may and may not be prescribed in the community, and by which professionals (Harman, 1999). Community nurses have not always been able to provide evidence-based wound care because of lack of appropriate products in the Drug Tariff (Young, 1994; Nazarko, 1995).

The Drug Tariff sets out the rules as to which drugs and appliances may and may not be prescribed in the community, and by which professionals (Harman, 1999). Community nurses have not always been able to provide evidence-based wound care because of lack of appropriate products in the Drug Tariff (Young, 1994; Nazarko, 1995).

Applications for inclusion on the tariff must meet three basic criteria:

- Is the product appropriate for use in the community?

- Is it cost-effective?

- Is it safe and of good quality?

A recent application for the inclusion of larvae in the Drug Tariff was turned down. This article examines the evidence base that fulfils the above criteria and supports the case for its inclusion.

Literature review
A great deal of the recent literature emerges from the Biosurgical Research Unit (BRU) at Bridgend in Wales where the team has undertaken much pioneering work in larval therapy. Bradley et al (1999) conducted a systematic review for the National Institute for Clinical Excellence (NICE) and found no randomised controlled trials (RCTs) evaluating the effectiveness of larval therapy or that compared debridement with no debridement. They stated that without such comparative studies it is unclear whether wound debridement is beneficial or expedites healing.

However, knowledge of the wound healing process alone would support the case for debridement (Cutting, 1994; Miller, 1997; Bale, 1997; Flanagan, 1997; Tong, 1999). Indeed, Vowden and Vowden (1999) suggested that it may be the most effective means of stimulating healing. Bradley et al's (1999) recommendations for research included detailed cost-effectiveness analyses of wound debridement and RCTs for larval therapy.

Thomas (2001) has criticised this NICE review, identifying serious flaws in the work that is the basis of national guidelines.

The clinical practice guidelines on the management of patients with venous leg ulcers (RCN, 1998) also highlighted the lack of RCTs, stating that current evidence does not support the use of larvae as debriding agents. In its summary, it stated that the strength of evidence for larval therapy was weak. However, in the same report consensus of an expert panel was considered to be sufficiently strong evidence for the holistic assessment of leg ulcers. It could be argued that the evidence from case history is as strong as the consensus of an expert panel.

Since these publications, one RCT has been published (Wayman et al, 2000), which indicated that larval therapy is cost-effective (£81.98, compared with £503.29, per patient, including nursing time). In addition every wound in the trial was debrided in the larvae group, whereas two of the six wounds using conventional methods were still not debrided one month later. Although it was a small sample (n=12), the results are encouraging.

Thomas and Jones (2001) reviewed recent case histories where debridement was achieved in an average of five days. They highlighted that these were selected case histories, which may not be representative of all wounds treated this way, and that the patients were receiving treatment from the nation's experts at the BRU, so the results may be biased towards better outcomes.

From discussions an ongoing survey at the BRU would indicate that 92% of wounds are improved by larval therapy, with 22% being debrided after two treatments (six days). Costs are reduced, largely due to fewer nursing visits being required and shorter time taken to debride. This compares with Wayman et al's results (2000). They concluded that the body of evidence for the value of this therapy is growing, despite the absence of RCTs.

Courtenay (1999) conducted a qualitative study into the clinical management of larval therapy. Twenty-three hospitals in the UK (including outpatients) were randomly selected from a total of 350 hospitals using the treatment. Clinical outcomes included reduced hospital stay and prevention of hospital admission, surgery or the use of antibiotics. This study recommended further research to evaluate effectiveness, the development of educational support, and clinical guidelines to include infection control, waste disposal, accountability and documentation. The issue of clinical waste disposal in primary care situations must be clarified.

Thomas et al (1996) indicated that larval therapy has been successful in infected wounds, including those with methicillin-resistant Staphylococcus aureus (MRSA). With the growing resistance to antibiotics this is highly significant for wound management, since an infected wound has been reported to be slower to heal (Flanagan, 1997).

The Drug Tariff
The Drug Tariff decrees what pharmacists can claim from the NHS for what they have dispensed. For many, it is the basis of doing business. The Department of Health decides what is included, but the Prescription Pricing Authority monitors prices monthly and can limit the availability of dressings and appliances, particularly expensive ones. Thus there is a bias towards cost, rather than evidence base, when deciding which products should be added. This does not reflect the quality called for in The New NHS: Modern, Dependable (Department of Health, 1997).

Harman (1999) discussed the process manufacturers must undergo in order for their products to be included in the Drug Tariff. In theory, any drug or wound care product can be prescribed by a GP, unless it is on the 'black list' (NHS, 2000). However, if it is not included in the Drug Tariff the NHS will not pay for the item and the cost must be borne by the dispensing chemist.

Several authors highlight the difficulty in giving consistent, evidence-based wound care in the community because dressings are unavailable on the Drug Tariff (Young, 1994; Nazarko, 1995; Pettingell, 1996; Holloway, 1998). This means that patients in the community receive substandard care unless practitioners find innovative ways of 'getting round the system' (Holloway, 1998).

Young (1994) discussed the hospital/community divide in wound care due to lack of availability of products on the Drug Tariff. Since then, more dressings have been added, including high-compression bandaging and products for cavity and malodorous wounds. This recognises the variety of wounds now treated in the community. She highlighted poor communication between hospital and community and identified training needs in wound care, since knowledge levels vary.

Discussion
The call for more RCTs has been mentioned (RCN, 1998; Bradley et al, 1999), and the National Health Research and Development Unit is believed to be funding some trials of larval therapy for wound debridement and the treatment of MRSA.

Randomised controlled trials have been called the gold standard in demonstrating the effectiveness of a treatment in a rigorously scientific manner (McCormack, 2000). However, they are not the only form of reliable evidence. Sarantakos (1998) commented that case studies are now accepted as valid forms of research when the research context is too complex for experimental studies. Rolfe (2001) discusses how postmodern theories dispute the dominance of scientific research in favour of accepting that other forms are equally valid.

The BRU has abandoned RCTs for several reasons. Most important, it was difficult to recruit subjects because, having heard and seen previous results, they all wanted to receive larval therapy. This supports McCormack's assertion (2000) that there is little point conducting an experiment if the outcome is well known.

When application for inclusion of larval therapy in the Drug Tariff was made, the BRU believed that the Department of Health was satisfied with the safety and cost-effectiveness of the therapy itself. The refusal suggests that the Department of Health does not consider it appropriate for use in the community. If this is the case, it is difficult to understand why.

Of course, practical issues need consideration, such as timing of treatments - due to the short shelf life of the larvae and the cool conditions required. However, these are no more difficult than other problems community nurses have overcome, such as phlebotomy and flu vaccinations, which require similar conditions.

Wound management constitutes a large part of the community nurse's role (Young, 1994), and these wounds may be sloughy, necrotic, or infected. With increasingly dependent patients being nursed at home community nurses need access to a wide range of products in order to provide evidence-based care. Without a full range of products in the Drug Tariff the care of patients in the community is compromised.

Nurses should be aware of current research, and, following thorough training, should consider larval therapy as part of holistic wound management, not as a last resort. Community nurses should push for its inclusion in the Drug Tariff to reduce the inequalities between hospital and community care. Once this has been achieved, we can begin to ask when it will be added to the Nurses' Formulary.

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