Petherick E S, O'Meara S, Spilsbury K, Iglesias C P, Nelson E A, Torgerson D J
Centre for Evidence Based Nursing, Department of Health Sciences, University of York, Heslington, YO10 5DD, UK.
BMC Med Res Methodol. 2006 Sep 1;6:43. doi: 10.1186/1471-2288-6-43.
A trial was commissioned to evaluate the effectiveness of larval therapy to debride and heal sloughy and necrotic venous leg ulcers. Larval therapy in the trial was to be delivered in either loose or bagged form. Researchers were concerned that resistance to larval therapy may threaten the feasibility of the trial. Additionally there was concern that the use of larval therapy may require a larger effect size in time to healing than originally proposed by the investigators.
To formally evaluate patient preferences a survey using two randomly allocated, nurse administered questionnaires was undertaken. Patients were randomised to receive one of the two following questionnaires (i) preferences between loose larvae and standard treatment (hydrogel) or (ii) patient preferences between bagged larvae and standard therapy (hydrogel). The study was undertaken in a Vascular Clinic, in an Outpatients Department of a large teaching hospital in the North of England. The sample consisted of 35 people aged 18 years and above with at least one leg ulcer of venous or mixed (venous and arterial) aetiology.
Approximately 25% of participants would not consider the use of larval therapy as an acceptable treatment option for leg ulcers, regardless of the method of containment. For the patients that would consider the use of larval therapy, different preferences in healing times required to use the therapy were observed depending upon the method of containment. The median response of those participants questioned about bagged larvae found that they would be willing to use this therapy even if they were equally able to achieve healing with the use of hydrogel by 20 weeks. For those participants questioned about the use of loose larvae complete healing would have to have taken place over 17 weeks for them to choose larvae as their preferred option rather than hydrogel. This difference was not significant (p = 0.075).
We found no evidence of widespread resistance to the utilisation of larval therapy from patients regardless of the method of larval therapy containment. These methods have the potential to inform sample size calculations where there are concerns of patient acceptability.
开展了一项试验以评估幼虫疗法清创和治愈腿部静脉性溃疡的坏死组织及愈合溃疡的有效性。该试验中的幼虫疗法将以松散或袋装形式进行。研究人员担心对幼虫疗法的抵抗可能会威胁到试验的可行性。此外，人们还担心与研究人员最初提出的相比，使用幼虫疗法可能需要更大的愈合效果量。
为了正式评估患者的偏好，采用了一项调查，使用两份随机分配、由护士管理的问卷。患者被随机分配接受以下两份问卷中的一份：（i）松散幼虫与标准治疗（水凝胶）之间的偏好；或（ii）袋装幼虫与标准治疗（水凝胶）之间的患者偏好。该研究在英格兰北部一家大型教学医院门诊部的血管诊所进行。样本包括35名18岁及以上的人，他们至少有一个由静脉或混合（静脉和动脉）病因引起的腿部溃疡。
无论幼虫的容纳方式如何，约25%的参与者不会将使用幼虫疗法视为腿部溃疡可接受的治疗选择。对于考虑使用幼虫疗法的患者，根据容纳方式的不同，观察到使用该疗法所需的愈合时间存在不同偏好。那些被问及袋装幼虫的参与者的中位数回答表明，即使使用水凝胶在20周时同样能够实现愈合，他们也愿意使用这种疗法。对于那些被问及使用松散幼虫的参与者，完全愈合必须在17周以上才能使他们选择幼虫作为首选方案而非水凝胶。这种差异不显著（p = 0.075）。
我们没有发现证据表明患者对使用幼虫疗法存在广泛抵抗，无论幼虫疗法的容纳方式如何。这些方法有可能为担心患者可接受性的样本量计算提供参考。
