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 ).