Lund Iréne, Lundeberg Thomas, Sandberg Louise, Budh Cecilia Norrbrink, Kowalski Jan, Svensson Elisabeth
Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, SE-171 77, Sweden.
BMC Med Res Methodol. 2005 Oct 4;5:31. doi: 10.1186/1471-2288-5-31.
Rating scales like the visual analogue scale, VAS, and the verbal rating scale, VRS, are often used for pain assessments both in clinical work and in research, despite the lack of a gold standard. Interchangeability of recorded pain intensity captured in the two scales has been discussed earlier, but not in conjunction with taking the influence of pain etiology into consideration.
In this cross-sectional study, patients with their pain classified according to its etiology (chronic/idiopathic, nociceptive and neuropathic pain) were consecutively recruited for self-assessment of their actual pain intensity using a continuous VAS, 0-100, and a discrete five-category VRS. The data were analyzed with a non-parametric statistical method, suitable for comparison of scales with different numbers of response alternatives.
An overlapping of the VAS records relative the VRS categories was seen in all pain groups. Cut-off positions for the VAS records related to the VRS categories were found lower in patients with nociceptive pain relative patients suffering from chronic/idiopathic and neuropathic pain. When comparing the VAS records transformed into an equidistant five-category scale with the VRS records, systematic disagreements between the scales was shown in all groups. Furthermore, in the test-retest a low percentage of the patients agreed to the same pain level on the VAS while the opposite hold for the VRS.
The pain intensity assessments on VAS and VRS are in this study, not interchangeable due to overlap of pain records between the two scales, systematic disagreements when comparing the two scales and a low percentage intra-scale agreement. Furthermore, the lower VAS cut-off positions relative the VRS labels indicate different meaning of the rated pain intensity depending on pain etiology. It is also indicated that the scales have non-linear properties and that the two scales probably have different interpretation. Our findings are in favor of using the VRS in pain intensity assessments but if still the VAS is preferred, the VAS data should be analyzed as continuous using statistical methods suitable for ordinal data. Furthermore, our findings indicate a risk to over or under estimate the patient's perceived pain when interpreting condensed VAS data.
尽管缺乏金标准，但视觉模拟评分法（VAS）和语言评分量表（VRS）等评分量表在临床工作和研究中常用于疼痛评估。此前已讨论过两种量表所记录的疼痛强度的互换性，但未结合疼痛病因的影响进行讨论。
在这项横断面研究中，根据病因（慢性/特发性、伤害性和神经性疼痛）对疼痛进行分类的患者被连续招募，使用连续的0 - 100的VAS和离散的五类VRS对其实际疼痛强度进行自我评估。采用非参数统计方法对数据进行分析，该方法适用于比较具有不同数量反应选项的量表。
在所有疼痛组中均观察到VAS记录与VRS类别之间存在重叠。与慢性/特发性和神经性疼痛患者相比，伤害性疼痛患者中与VRS类别相关的VAS记录的截断位置更低。当将转换为等距五类量表的VAS记录与VRS记录进行比较时，所有组中量表之间均显示出系统性差异。此外，在重测中，同意VAS上相同疼痛水平的患者比例较低，而VRS则相反。
在本研究中，VAS和VRS的疼痛强度评估不可互换，原因在于两种量表之间的疼痛记录存在重叠、比较两种量表时存在系统性差异以及量表内一致性百分比低。此外，相对于VRS标签，VAS较低的截断位置表明根据疼痛病因，所评定的疼痛强度具有不同含义。还表明这些量表具有非线性特性，并且两种量表可能具有不同的解释。我们的研究结果支持在疼痛强度评估中使用VRS，但如果仍然首选VAS，则应使用适用于有序数据的统计方法将VAS数据作为连续数据进行分析。此外，我们的研究结果表明，在解释简化的VAS数据时，存在高估或低估患者感知疼痛的风险。
