Queen Mary University of London, Unit for Social and Community Psychiatry, Barts and the London School of Medicine, London, UK.
Psychol Med. 2011 Feb;41(2):277-89. doi: 10.1017/S0033291710000784. Epub 2010 Apr 21.
Patient-reported outcomes (PROs) are widely used for evaluating the care of patients with psychosis. Previous studies have reported a considerable overlap in the information captured by measures designed to assess different outcomes. This may impair the validity of PROs and makes an a priori choice of the most appropriate measure difficult when assessing treatment benefits for patients. We aimed to investigate the extent to which four widely established PROs [subjective quality of life (SQOL), needs for care, treatment satisfaction and the therapeutic relationship] provide distinct information independent from this overlap.
Analyses, based on item response modelling, were conducted on measures of SQOL, needs for care, treatment satisfaction and the therapeutic relationship in two large samples of patients with psychosis.
In both samples, a bifactor model matched the data best, suggesting sufficiently strong concept factors to allow for four distinct PRO scales. These were independent from overlap across measures due to a general appraisal tendency of patients for positive or negative ratings and shared domain content. The overlap partially impaired the ability of items to discriminate precisely between patients from lower and higher PRO levels. We found that widely used sum scores were strongly affected by the general appraisal tendency.
Four widely established PROs can provide distinct information independent from overlap across measures. The findings may inform the use and further development of PROs in the evaluation of treatments for psychosis.
患者报告的结局（PROs）被广泛用于评估精神病患者的护理。先前的研究报告称，旨在评估不同结局的测量方法所捕获的信息存在相当大的重叠。这可能会损害 PROs 的有效性，并使得在评估患者治疗益处时难以事先选择最合适的测量方法。我们旨在研究广泛使用的四种 PROs[主观生活质量（SQOL）、护理需求、治疗满意度和治疗关系]在多大程度上提供了独立于这种重叠的独特信息。
基于项目反应模型的分析，对两种大型精神病患者样本中的 SQOL、护理需求、治疗满意度和治疗关系的测量方法进行了分析。
在两个样本中，双因素模型最符合数据，这表明有足够强的概念因素来支持四个独立的 PRO 量表。这些量表与测量之间的重叠无关，因为患者对正性或负性评分以及共享的领域内容存在一般评价倾向。重叠部分削弱了项目在区分来自较低和较高 PRO 水平的患者方面的精确区分能力。我们发现，广泛使用的总和评分受到一般评价倾向的强烈影响。
四种广泛使用的 PROs 可以提供独立于测量之间重叠的独特信息。这些发现可能为 PROs 在评估精神病治疗中的应用和进一步发展提供信息。
