Evaluating postherniorrhaphy groin pain: Visual Analogue or Verbal Rating Scale?

Abstract

Several tools for pain measurement including a Visual Analogue Scale (VAS) and a Verbal Rating Scale (VRS) are currently used in patients with chronic pain. The aim of the present study was to determine which of these two pain tests performs optimally in patients following groin hernia repair. A questionnaire identified pain level in a cohort of patients that had previously undergone corrective groin hernia surgery. Current pain intensity was graded on a four-point VRS scale (no pain, mild, moderate or severe pain) and on a 100-mm VAS scale (0=no pain, 100=unbearable). "Scale failure" (one or both tests not completed correctly) was determined, and cut-off points for the VAS test were calculated by creating the optimum kappa coefficient between both tools. The response rate was 78.2% (706/903). Scale failure was present in VAS tests more than VRS (VAS: 12.5%, 88/706 vs. VRS: 2.8%, 20/706; P<0.001). Advanced age was a risk factor for scale failure (P<0.001). The four categories of VRS corresponded to mean VAS scores of 1, 20, 42, and 78 mm, respectively. VAS categories associated with the highest kappa coefficient (k=0.78) were as follows: 0-8=no pain, 9-32=mild, 33-71=moderate, >71=severe pain. VAS scores grouped per VRS category showed considerable overlap. Age and sex did not significantly influence cut-off points. Because of lower scale failure rates and overlapping VAS scores per VRS category, the VRS should be favored over the VAS in future postherniorrhaphy pain assessment. If VAS is preferred, the presented cut-off points should be utilized.