How does measured olfactory function correlate with self-ratings of the sense of smell in patients with nasal polyposis?

Authors

  • Duc Trung Nguyen MD, MSc,

    Corresponding author
    1. Department of ENT–Head and Neck Surgery,
    2. INSERM, CIC-EC CIE6, Nancy, France
    • Département d'Otorhinolaryngologie et Chirurgie Cervico-Faciale, Hôpital Central, Centre Hospitalier Universitaire de Nancy, 29, Av. du Maréchal de Lattre de Tassigny, Nancy 54000, France
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  • Phi-Linh Nguyen-Thi MD, PhD,

    1. Clinical Epidemiology and Evaluation Department, University Hospital of Nancy, Nancy
    2. INSERM, CIC-EC CIE6, Nancy, France
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  • Roger Jankowski MD, PhD

    1. Department of ENT–Head and Neck Surgery,
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  • The authors have no funding, financial relationships, or conflicts of interest to disclose.

Abstract

Objectives/Hypothesis:

The objectives of this study were to investigate correlations, before and after surgery, between olfactory function self-ratings and measurements, and self-ratings of nasal obstruction and smell; and to establish cutoff points of self-rating scores for smell reduction in patients with nasal polyposis (NP).

Study Design:

Prospective study.

Methods:

A total of 80 patients with NP (36 women, 44 men; aged 49 ± 4 years) were enrolled. Self-ratings (0- to 10-point scale) and measurements of olfactory function with standardized Sniffin' Sticks odor threshold and identification tests were assessed 1 day before surgery, and at 6 weeks (26–78 days) and 7 months (132–318 days) after surgery. Relationships were studied with Spearman correlation coefficients. Cutoff points of self-rating scores for olfactory deficit were established using the receiver operating characteristic curve.

Results:

Overall, olfactory function self-ratings and measurements correlated strongly preoperatively (r = −0.66, P < .0001) and postoperatively (r = −0.67 at 6 weeks and −0.66 at 7 months, P < .0001). This relationship was better in patients with previous surgery. The correlation was weaker before surgery (r = −0.35, P = .01) than after in hyposmic/anosmic patients (r = −0.74, P < .0001 at 6 weeks and r = −0.73, P = .0002 at 7 months) and was not found in normosmic patients. Self-ratings of nasal patency and smell were not correlated when two complaints were dissociated. Cutoff points of self-rating scores for smell reduction were nine units preoperatively and five units postoperatively.

Conclusions:

Self-ratings and measurements of olfactory function correlated well before and after surgery in NP patients with olfactory deficits. Self-ratings were not reliable pre- and postoperatively in normosmic patients.

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