Investigation of prognostic factors for post-traumatic olfactory dysfunction

Background: Post-traumatic olfactory dysfunction is common but has a poor prognosis. The purpose of this study was to analyze the effect of clinical features on improvements in post-traumatic olfactory dysfunction. Methods: From 2007 to 2013, patients with post-traumatic olfactory dysfunction were enrolled. Olfactory function was assessed using the Sniffin' Sticks test at the first and final visits. Olfactory improvement was defined as a change in olfactory state to an improved level. Variables with a potential effect on improvements in olfactory dysfunction, including age, sex, time from trauma to first visit, initial olfactory function, observation time, and olfactory bulb integrity, were entered into logistic regression analysis. Results: In total, 107 patients were included, with a mean age of 40 years. The mean follow-up period was 9.4 months. Eighteen patients (16.8%) had improvements with regard to olfactory function. No clinical factors were found to influence olfactory recovery in univariate and multivariate analyses (all p > 0.05). In addition, there were no differences in clinical features between the patients with and without olfactory recovery (all p > 0.05). Conclusion: No significantly favorable prognostic factors for post-traumatic olfactory recovery were identified, reflecting, to some extent, the poor prognosis of post-traumatic olfactory damage. The results of this study provide useful information that clinical physicians can use when counseling patients with post-traumatic olfactory disorder regarding the prognosis, observation choice, and possible treatment strategy.