Citation: Pirola, F.; Giombi, F.; Ferreli, F.; Costantino, A.; Mercante, G.; Paoletti, G.; Heffler, E.; Canonica, G.W.; Settimi, S.; De Corso, E.; et al. Cross-Cultural Validation of the Short Version of the Questionnaire of Olfactory Disorders—Negative Statements into Italian: Towards Personalized Patient Care. J. Pers. Med. 2022, 12, 2010. https://doi.org/ 10.3390/jpm12122010 Academic Editors: José Carmelo Adsuar Sala and Angela Renee Starkweather Received: 24 August 2022 Accepted: 2 December 2022 Published: 4 December 2022 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). Journal of Personalized Medicine Article Cross-Cultural Validation of the Short Version of the Questionnaire of Olfactory Disorders—Negative Statements into Italian: Towards Personalized Patient Care Francesca Pirola 1,2 , Francesco Giombi 1,2, *, Fabio Ferreli 1,2 , Andrea Costantino 1,2 , Giuseppe Mercante 1,2 , Giovanni Paoletti 2,3 , Enrico Heffler 2,3 , Giorgio Walter Canonica 2,3 , Stefano Settimi 4 , Eugenio De Corso 5 , Giuseppe Spriano 1,2 and Luca Malvezzi 1,2 1 Otorhinolaryngology Head & Neck Surgery Unit, IRCCS Humanitas Research Hospital, Via Manzoni 56, Rozzano, 20089 Milan, Italy 2 Department of Biomedical Sciences, Humanitas University, Via Rita Levi Montalcini 4, Pieve Emanuele, 20090 Milan, Italy 3 Personalized Medicine, Asthma and Allergy, IRCCS Humanitas Research Hospital, Via Manzoni 56, Rozzano, 20089 Milan, Italy 4 Department of Head and Neck and Sensory Organs, Catholic University of the Sacred Hearth, 00168 Rome, Italy 5 Unit of Otorhinolaryngology-Head and Neck Surgery, A. Gemelli Hospital Foundation IRCCS, 00168 Rome, Italy * Correspondence: francesco.giombi@gmail.com; Tel.: +39-02-8224-7550 Abstract: Given the high burden of olfactory dysfunction worldwide, recently increased due to the COVID-19 pandemic, it is mandatory to adopt a specific questionnaire to assess the impact of olfactory impairment on quality of life, to be used in clinical practice. The aim of this study is to adapt and validate the short version of the Questionnaire of Olfactory Disorders-Negative Statements (svQOD-NS) for Italian. In the pilot phase, the Italian version of the questionnaire (ITA-svQOD-NS) was produced following recommended guidelines. It was then given to 50 healthy subjects and 50 patients (affected by either nasal polyposis or septal deviation), and results were compared to those of other widely used questionnaires. Test-retest reliability was assessed on a sample of 25 patients. All 50 patients repeated the questionnaires at one and nine months after surgery. The internal consistency of ITA-svQOD-NS measured with Cronbach α was excellent (α = 0.92). The intraclass correlation coefficient for test-retest reliability was also optimal (0.93; 95%CI: 0.90–0.96). Concurrent validity tested with the Pearson coefficient was significant with all other tests administered; also, concerning responsiveness, statistically significant differences were obtained between pre- and post-operative conditions. ITA-svQOD-NS showed high internal consistency, test-retest reliability, and significant correlation with all most-used clinical questionnaires; thus, it can be efficiently applied to assess olfaction-related QoL in the Italian population. Keywords: questionnaire; olfactory dysfunction; quality of life; chronic rhinosinusitis; septal deviation 1. Introduction Olfactory dysfunction (OD) is a common clinical condition in otolaryngological clinical practice. It has been reported to affect more than 200,000 patients per year in the United States, with age-related incidence, especially after 60 years [1,2]. OD may be associated with several disorders, either otolaryngological (e.g., common viral upper airways affections, acute or chronic rhinosinusitis, and benign or malignant sinonasal tumors) [3], or neurolog- ical (e.g., Parkinson’s or Alzheimer ’s disease) [4,5]. Recently, OD has been recognized as an alarming symptom that should raise suspicion for COVID-19 infection [6], especially in otherwise asymptomatic carriers [7,8]; it also proved to be useful in monitoring COVID-19 clinical evolution [9]. J. Pers. Med. 2022, 12, 2010. https://doi.org/10.3390/jpm12122010 https://www.mdpi.com/journal/jpm