Monitoring olfactory function in chronic rhinosinusitis and the effect of disease duration on outcome.

BACKGROUND: Our primary aim in this study was to determine which of the "Sniffin' Sticks" subtest components (threshold, discrimination, or identification) best reflect overall change in olfactory function during treatment for chronic rhinosinusitis (CRS). Our secondary aim was to determine whether duration of CRS affects olfactory outcomes after treatment.

METHODS: A retrospective cohort study was performed. Sniffin' Sticks test scores from patients medically treated for CRS at our center from 1999 to 2016 were analyzed. Only patients with 2 test scores available were included.

RESULTS: Results from 408 patients were included (mean age, 56 years; male:female ratio, 217:191). There was a statistically significant improvement in threshold (T), discrimination (D), and identification (I) scores as well as the composite "TDI" score between the two testing sessions. Controlling for age, there was a significantly greater improvement in composite TDI score in patients with CRS of ≤24 months duration. As expected, we found statistically significant correlations between change in overall composite TDI score and change in threshhold, discrimination, and identification, between sessions. Of the individual subcomponents, change in discrimination correlated best with change in composite TDI score (r = 0.82, p < 0.0001). This relationship was maintained irrespective of duration of CRS.

CONCLUSIONS: In patients with CRS, odor discrimination appears to best reflect overall changes in olfactory function, as determined using the composite TDI score. Furthermore, olfactory outcomes are better when treatment is started sooner.