Objectives This study aims to determine the association between parosmia
and clinically relevant recovery in olfactory function in patients with
smell loss receiving olfactory training. Design and setting This was a
retrospective cohort study of patients that received olfactory training.
Adult patients with the major complaint of quantitative smell loss were
recruited and treated at several ENT clinics in German between 2008 and
2018. Participants A total of 243 participants were included. Main
outcome measures Changes in olfactory function after olfactory training.
Age, gender, baseline olfactory function, etiology and duration of smell
loss, duration of training, and presence of parosmia and phantosmia were
assessed for their impact on clinically relevant changes in overall and
subdimension olfactory function using binary logistic regression
analysis. Results Relevant improvements in discrimination function were
more likely in those that had lower baseline olfactory function,
postinfectious reasons compared to posttraumatic or idiopathic causes
and those that had parosmia at initial visit. Relevant improvements in
odour identification were more likely in those that had a lower baseline
olfactory function, female gender, and in those who had parosmia at the
first visit. Clinically significant improvements in odour threshold were
more likely in postinfectious causes compared to posttraumatic reasons
and those who were older in age. Conclusions This study demonstrated
that the presence of parosmia is associated with clinically relevant
recovery in olfactory function in patients with smell loss receiving
olfactory training.