Validation of Visual Analogue Scale for loss of smell as a quick test in chronic rhinosinusitis with nasal polyps.

Abstract

Diagnostic criteria of chronic rhinosinusitis with nasal polyps (CRSwNP) include, among others, olfactory dysfunction (OD). We hypothesize that patients suffering with CRSwNP are good at self-assessing their sense of smell through visual analogue scale (VAS) compared to smell tests. A controlled cross-sectional study was planned. Adults diagnosed with severe CRSwNP waiting for endoscopic sinus surgery were included. A cohort of healthy controls was also studied. All participants performed Barcelona smell test (BAST-24), sinonasal outcomes test 22 (SNOT-22), and VAS for loss of smell. CRSwNP underwent blood test (eosinophils count, total serum IgE), CT scan (Lund-Mackay Score), and nasal endoscopy. 138 severe CRSwNP and 40 controls subjects were included. The BAST-24 identification score was strongly correlated with the VAS score in the CRSwNP group (rho=-0.79, p<0.001) but not in the control group (rho=-0.14; p=0.39), this difference between groups being statistically significant (p<0.001). A significant correlation of SNOT-22 item 21 (loss of smell) was also found with BAST-24 identification (rho=-0.65, p<0.001), this difference being statistically significant (Z=-2.43; p=0.015). In the ROC curve, the area under the curve (AUC) was 0.85 with 72.5% sensitivity and 93.1% specificity. This study demonstrates a potential role of the VAS score for the screening of OD in severe CRSwNP in daily clinical practice.