Health-Related and Specific Olfaction-Related Quality of Life in Patients with Chronic Functional Anosmia or Severe Hyposmia

Objectives/Hypothesis: To measure health-related and olfaction-related quality of life (QoL) in patients with permanent, severe hyposmia or functional anosmia. Study Design: A case study in a university ENT department of patients with severe olfactory dysfunction defined by Sniffin' Sticks olfactory test kit with a score for odor threshold, discrimination, and identification (TDI) < 20 and a dysfunction lasting longer than 6 months. Methods: Assessment of QoL by using the SF-36 Health Survey questionnaire and the Questionnaire for Olfactory Dysfunction (QOD). Results: A total of 958 patients were tested for smell disturbances from 1999 to 2009. Surveys were mailed to 527 patients who fulfilled the inclusion criteria; 280 (53%) returned completed surveys. All SF-36 domains in severely hyposmic and anosmic patients were lower than in the German normal population. Lower SF-36 QoL was found for some domains in female patients, older patients, and hyposmic patients (P < .05 for all groups). Based on the QOD, women showed more parosmia, and anosmic patients had more olfactory-related impairment (P < .05 for both); in general, higher olfactory impairment and higher parosmia score measured by QOD correlated with lower TDI values (all P < .05). Multivariate analysis revealed, for SF-36 domains, the following independent risk factors: female sex was a risk factor for bodily pain; higher age was a risk factor for physical functioning and role, bodily pain, and general health; hyposmia was a risk factor for bodily pain and mental health; QOD QoL was a risk factor for all SF-36 scales; and QOD parosmia was a risk factor for physical role (all P < .05). Conclusions: QoL is severely impaired in patients with chronic severe hyposmia or anosmia. The QOD allows a more olfaction-specific assessment of QoL than the SF-36 instrument.