Association between aetiology and age with relevant
improvement in threshold
We were next interested in determining which of above-mentioned smell
loss-related variables were associated with clinically relevant
improvements in olfactory threshold performance (defined as T
improvement greater or equal 2.5 points) at follow up visit.
Binary logistic regression analysis revealed that clinically relevant
improvements in threshold function were more likely in postinfectious OD
compared to posttraumatic OD (aOR, 0.22, 95%CI, 0.06-0.83) and those
who were older in age (aOR, 1.08, 95%CI 1.03-1.14).
Because we identified recovery in sub-dimensions T, D, and I to be
differently predicted by smell-loss related factors, we checked for
similarities between these olfactory dimensions. Therefore, hierarchical
cluster analysis was performed. Cluster analysis indicated that recovery
of olfactory function discrimination and identification (both
suprathreshold) was distinct from threshold improvements (Fig
1 ).