PEG: A 3-item Questionnaire for Grading Orofacial Pain Chronification

Objectives: The PEG questionnaire consists of three items derived from the BPI (Brief Pain Inventory) regarding average Pain intensity (P), interference Enjoyment of life (E), and interference of General activity (G) during the past week. Purpose of this study was to examine the statistical properties of the PEG questionnaire for grading the chronification of non-dental orofacial pain.
Methods: 268 consecutive patients with orofacial pain of non-dental origin filled out the Graded Chronic Pain Status (GCPS, version 2) and the PEG questionnaire. Correlation between the scores was examined with non-parametric tests (Spearman’s ρ). The internal consistency of PEG was tested with Cronbach’s α. Differences between groups were examined with the Mann-Whitney-U-test. Level of significance was set at p≤0.05.
Results: The mean age of the 213 patients (158 female), who fulfilled the inclusion criteria and were included in the analysis, was 43.1±16.7 years. 49.3% of the sample had some orofacial pain-related disability; the mean overall characteristic pain intensity (CPI) was 51.2±23.2 and average PEG score was 13.0±8.1. There were no significant differences between both sexes for any score. The correlation between pain related disability and PEG sum score was strong, significant and positive (ρ=0.77; p<0.001). The internal consistency of the PEG questionnaire was high (Cronbach’s α=0.86). Analysis of the ROC-curve showed that a cut-off value of 11 points in the PEG sum score yields adequate validity (Sensitivity=0.91; Specificity=0.78). Grading patients with the GCPS and the PEG (cut-off=11) showed strong, significant and positive (ρ=0.7; p<0.001) correlation. Using two cut-off points (upper=16, Sensitivity=0.7, Specificity=0.9; low=10, Sensitivity=0.9, Specificity=0.6) patients could be divided into three chronification groups (no/low, medium and high pain related disability) which differ from each other significantly (Kruskal-Wallis p<0.001).
Conclusions: The three-item PEG questionnaire is appropriate for grading non-dental orofacial pain chronification. We propose its use as part of screening for orofacial pain.