Evaluation

Structured assessment tools may be used within clinical practice as well as in research evaluation. Specifically they are helpful as treatment or nursing care evaluation tools to monitor the progress of therapy or intervention. One such example of evaluation is the use of the PASI score. A 75% improvement (PASI75) is well established as a clinically meaningful endpoint for trials but PASI50 (50% improvement) is also considered by some to be a clinically valid endpoint. Common clinical guidelines, such as those for biological therapy for psoriasis, now incorporate PASI parameters to specify the level of disease severity required to permit treatment (Smith et al., 2005; National Institute for Health and Clinical Excellence [NICE], 2008).

Consideration is required of the timing of the evaluation measurement; for example, if applying tar, there will be a slow response to treatment over a period of weeks. Both health professionals and patients need to give recognition of the duration over which interventions are typically effective, since patients may abandon treatments, which they believe are not working. Research evidence suggests patients may use timing of the treatment effect as a criterion for judging the effectiveness of their therapy in psoriasis care (Ersser et al., 2002). Clinicians need to take account of the criteria that patients use in evaluating treatment regimens. Premature evaluative measurements may provide a misleading picture of the effectiveness of a particular therapy; therefore, there is a need to consider the evidence underlying the duration of treatments. Practitioners also need to be mindful of the role standardised tools play (see e.g. Table 3.7) as measures at key endpoints in the research evaluation of existing or new therapies; this will be useful when interpreting research results within clinical papers and understanding the way in which evidence may inform the clinical guidelines used by nurses.