Clinical Trials Research Unit, University of Leeds, Leeds, UK.
Mid Yorks Hospitals NHS Trust, Wakefield, UK.
Trials. 2021 Apr 28;22(1):308. doi: 10.1186/s13063-021-05262-0.
PRESSURE 2 is a randomised evaluation of the clinical and cost-effectiveness of two types of mattress for the prevention of pressure ulcers (PUs). The primary clinical endpoint was time to development of a category ≥2 PU. The current 'gold standard' for PU identification is expert clinical assessment. Due to the mattress appearance, a blinded assessment of the endpoint is not possible. This poses a risk to the internal validity of the study. A possible approach is to use photographs of skin sites, with central blinded review. However, there are practical and scientific concerns including patients' consent to photographs, burden of data collection, photograph quality, data completeness and comparison of photographs to the current 'gold standard'. This paper reports the findings of the PRESSURE 2 photographic validation sub-study.
Where consent was obtained, photographs were taken of all category ≥2 PUs on the first presentation to assess over-reporting, and for the assessment of under-reporting, a random sample of 10% patients had an assessment by an independent clinical assessor who also photographed two skin sites. The staff were trained in taking and transferring photographs using standardised procedures and equipment. A card included in the photograph recorded participant details and a 'greyscale' for correction of white balance during processing. Three blinded reviewers assessed the photographs and rated how confident they were in their assessment.
The trial recruited 2029 patients; 85% consented to photography, and 532 photographs were received and used in the blinded central review. The level of confidence varied by skin classification with more confidence observed when the skin was assessed as being less severe than a category ≥2 PU. Overall, there was a very good reliability compared to the gold standard expert clinical assessment (87.8%, kappa 0.82).
Study findings have usefully informed the scientific and practical issues of blinded assessment of PU status to reducing the risk of bias in medical device trials. The reliability of central blinded expert photography was found to be 'very good' (PABAK). Photographs have been found to be an acceptable method of data validation for participants. Methods to improve the quality of photographs would increase the confidence in the assessments.
ISRCTN Registry ISRCTN01151335 . Registered on 19 April 2013.
PRESSURE 2 是一项针对两种床垫预防压疮（PU）的临床和成本效益的随机评估。主要的临床终点是发展为≥2 级 PU 的时间。PU 识别的当前“金标准”是专家临床评估。由于床垫的外观，对终点进行盲法评估是不可能的。这对研究的内部有效性构成了风险。一种可能的方法是使用皮肤部位的照片，并进行中心盲法评估。然而，存在实际和科学方面的担忧，包括患者对照片的同意、数据收集的负担、照片质量、数据完整性以及将照片与当前的“金标准”进行比较。本文报告了 PRESSURE 2 摄影验证子研究的结果。
在获得同意的情况下，对所有首次就诊时出现的≥2 级 PU 拍摄照片，以评估是否存在过度报告，并对 10%的随机患者样本进行评估，由独立临床评估员进行评估，评估员还拍摄了两个皮肤部位的照片。工作人员接受了使用标准化程序和设备拍摄和传输照片的培训。照片中附有一张卡片，记录了参与者的详细信息和用于在处理过程中校正白平衡的“灰度”。三名盲法审核员评估了照片，并对他们的评估有多大信心进行了评级。
试验共招募了 2029 名患者；85%的患者同意拍摄照片，共收到并使用了 532 张照片进行盲法中心审查。信心水平因皮肤分类而异，当皮肤被评估为比≥2 级 PU 程度较轻时，信心水平更高。总体而言，与黄金标准专家临床评估相比，其可靠性非常好（87.8%，kappa 0.82）。
研究结果为减少医疗器械试验中的偏倚风险，提供了有关 PU 状态盲法评估的科学和实际问题的有用信息。中央盲法专家摄影的可靠性被认为是“非常好”（PABAK）。已发现照片是参与者数据验证的一种可接受方法。改进照片质量的方法将提高评估的可信度。
ISRCTN 注册处 ISRCTN01151335。于 2013 年 4 月 19 日注册。
