Study population
This pooled data analysis included adult participants from three
previously published studies on OT.11–13 Adult
patients were either self-referrals or referred from outside
institutions to tertiary-care otorhinolaryngology departments between
2008 and 2018. Inclusion criteria were posttraumatic, postinfectious,
and idiopathic smell loss. Exclusion criteria were TDI above 30.5
(indicating normal olfactory function), pregnancy, and acute or chronic
sinonasal diseases. At the initial visit, patients were asked for
presence of parosmia or phantosmia (binary outcome of yes and no), time
since onset of OD (in month), and possible causes for their smell loss.
Diagnosis was made based on the recent “Position paper of olfactory
dysfunction1” (Table 1 ).