The development and validation of the Smell-Qx questionnaire, based on a systematic review of the literature and the COMET initiative on the development of core outcome sets for clinical trials in olfactory disorders

Matt Lechner; Alexander Fjaeldstad; Umar Rehman; Jacklyn Liu; David Boniface; Jim Boardman; Duncan Boak; Aytug Altundag; Johannes Frasnelli; Simon Gane; Eric Holbrook; Julien Hsieh; Caroline Huart; Iordanis Konstantinidis; Basile N. Landis; Valerie J. Lund; Alberto Macchi; Eri Mori; Christian Mueller; Joaquim Mullol; Simona Negoias; Zara M. Patel; Jayant M. Pinto; Sophia Poletti; Vijay Ramakrishnan; Philippe Rombaux; Jan Vodicka; Antje Welge-Luessen; Katherine L. Whitcroft; Carol Yan; Carl Philpott; Thomas Hummel

doi:10.1002/alr.23604

The development and validation of the Smell-Qx questionnaire, based on a systematic review of the literature and the COMET initiative on the development of core outcome sets for clinical trials in olfactory disorders

Matt Lechner, Alexander Fjaeldstad, Umar Rehman, Jacklyn Liu, David Boniface, Jim Boardman, Duncan Boak, Aytug Altundag, Johannes Frasnelli, Simon Gane, Eric Holbrook, Julien Hsieh, Caroline Huart, Iordanis Konstantinidis, Basile N. Landis, Valerie J. Lund, Alberto Macchi, Eri Mori, Christian Mueller, Joaquim MullolSimona Negoias, Zara M. Patel, Jayant M. Pinto, Sophia Poletti, Vijay Ramakrishnan, Philippe Rombaux, Jan Vodicka, Antje Welge-Luessen, Katherine L. Whitcroft, Carol Yan, Carl Philpott, Thomas Hummel

Research output: Contribution to journal › Article › peer-review

Abstract

Background: Olfactory dysfunction affects up to 22% of the population. Accurate assessment is vital for diagnosis and tracking outcomes, often using patient-reported outcome measures (PROMs).

Aims: We aimed to develop and validate a novel questionnaire for assessing olfactory and gustatory dysfunction.

Methods: A systematic review identified existing smell and taste questionnaires, followed by item generation and selection. After two Delphi cycles and consultation with a large panel of smell and taste experts, the Smell-Qx questionnaire was developed. A validation study recruited patients from smell and taste clinics (cases) and general ENT clinics (controls) to complete the Smell-Qx. Additionally, patients with smell and taste disorders underwent psychophysical testing using Sniffin' Stick Threshold, Discrimination, and Identification (TDI) tests.

Results: The Smell-Qx is an 11-domain instrument, with five core domains used for total score calculation and six history/quality-of-life domains for obtaining a comprehensive history. The validation study recruited 60 participants (32 patients with smell/taste disorders and 28 controls). Items showed acceptable to significant internal consistency (Cronbach's α: 0.64?0.97) and test-retest reliability (ICC: 0.65?0.99, p < 0.001). The Smell-Qx was effective at distinguishing patients with smell and taste disorders from controls (t = 9.99, df = 58, p < 0.0001). Concurrent criterion validity was good with overall SATD-related quality of life (r = 0.43, p = 0.015), as well as with the smell loss domain and overall smell TDI scores (r = ?0.54, p = 0.011).

Conclusion: The Smell-Qx is a reliable and valid PROM for assessing olfactory and self-reported gustatory disorders, capturing symptom severity and quality-of-life impact. It can integrate into a multi-modal assessment approach alongside psychophysical testing.

Original language	English
Article number	e23604
Journal	International Forum of Allergy & Rhinology
Early online date	9 May 2025
DOIs	https://doi.org/10.1002/alr.23604
Publication status	E-pub ahead of print - 9 May 2025

Keywords

gustatory dysfunction
olfactory dysfunction
patient-reported outcome measures

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Lechner, M., Fjaeldstad, A., Rehman, U., Liu, J., Boniface, D., Boardman, J., Boak, D., Altundag, A., Frasnelli, J., Gane, S., Holbrook, E., Hsieh, J., Huart, C., Konstantinidis, I., Landis, B. N., Lund, V. J., Macchi, A., Mori, E., Mueller, C., ... Hummel, T. (2025). The development and validation of the Smell-Qx questionnaire, based on a systematic review of the literature and the COMET initiative on the development of core outcome sets for clinical trials in olfactory disorders. International Forum of Allergy & Rhinology, Article e23604. Advance online publication. https://doi.org/10.1002/alr.23604

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title = "The development and validation of the Smell-Qx questionnaire, based on a systematic review of the literature and the COMET initiative on the development of core outcome sets for clinical trials in olfactory disorders",

abstract = "Background: Olfactory dysfunction affects up to 22% of the population. Accurate assessment is vital for diagnosis and tracking outcomes, often using patient-reported outcome measures (PROMs). Aims: We aimed to develop and validate a novel questionnaire for assessing olfactory and gustatory dysfunction. Methods: A systematic review identified existing smell and taste questionnaires, followed by item generation and selection. After two Delphi cycles and consultation with a large panel of smell and taste experts, the Smell-Qx questionnaire was developed. A validation study recruited patients from smell and taste clinics (cases) and general ENT clinics (controls) to complete the Smell-Qx. Additionally, patients with smell and taste disorders underwent psychophysical testing using Sniffin' Stick Threshold, Discrimination, and Identification (TDI) tests. Results: The Smell-Qx is an 11-domain instrument, with five core domains used for total score calculation and six history/quality-of-life domains for obtaining a comprehensive history. The validation study recruited 60 participants (32 patients with smell/taste disorders and 28 controls). Items showed acceptable to significant internal consistency (Cronbach's α: 0.64?0.97) and test-retest reliability (ICC: 0.65?0.99, p < 0.001). The Smell-Qx was effective at distinguishing patients with smell and taste disorders from controls (t = 9.99, df = 58, p < 0.0001). Concurrent criterion validity was good with overall SATD-related quality of life (r = 0.43, p = 0.015), as well as with the smell loss domain and overall smell TDI scores (r = ?0.54, p = 0.011). Conclusion: The Smell-Qx is a reliable and valid PROM for assessing olfactory and self-reported gustatory disorders, capturing symptom severity and quality-of-life impact. It can integrate into a multi-modal assessment approach alongside psychophysical testing.",

keywords = "gustatory dysfunction, olfactory dysfunction, patient-reported outcome measures",

author = "Matt Lechner and Alexander Fjaeldstad and Umar Rehman and Jacklyn Liu and David Boniface and Jim Boardman and Duncan Boak and Aytug Altundag and Johannes Frasnelli and Simon Gane and Eric Holbrook and Julien Hsieh and Caroline Huart and Iordanis Konstantinidis and Landis, {Basile N.} and Lund, {Valerie J.} and Alberto Macchi and Eri Mori and Christian Mueller and Joaquim Mullol and Simona Negoias and Patel, {Zara M.} and Pinto, {Jayant M.} and Sophia Poletti and Vijay Ramakrishnan and Philippe Rombaux and Jan Vodicka and Antje Welge-Luessen and Whitcroft, {Katherine L.} and Carol Yan and Carl Philpott and Thomas Hummel",

note = "Data Availability Statement: The data that support the findings of this study are available from the corresponding author upon reasonable request. Funding: The authors received no specific funding for this work.",

year = "2025",

month = may,

day = "9",

doi = "10.1002/alr.23604",

language = "English",

journal = "International Forum of Allergy & Rhinology",

issn = "2042-6976",

publisher = "Wiley",

}

Lechner, M, Fjaeldstad, A, Rehman, U, Liu, J, Boniface, D, Boardman, J, Boak, D, Altundag, A, Frasnelli, J, Gane, S, Holbrook, E, Hsieh, J, Huart, C, Konstantinidis, I, Landis, BN, Lund, VJ, Macchi, A, Mori, E, Mueller, C, Mullol, J, Negoias, S, Patel, ZM, Pinto, JM, Poletti, S, Ramakrishnan, V, Rombaux, P, Vodicka, J, Welge-Luessen, A, Whitcroft, KL, Yan, C, Philpott, C & Hummel, T 2025, 'The development and validation of the Smell-Qx questionnaire, based on a systematic review of the literature and the COMET initiative on the development of core outcome sets for clinical trials in olfactory disorders', International Forum of Allergy & Rhinology. https://doi.org/10.1002/alr.23604

The development and validation of the Smell-Qx questionnaire, based on a systematic review of the literature and the COMET initiative on the development of core outcome sets for clinical trials in olfactory disorders. / Lechner, Matt; Fjaeldstad, Alexander; Rehman, Umar et al.
In: International Forum of Allergy & Rhinology, 09.05.2025.

Research output: Contribution to journal › Article › peer-review

TY - JOUR

T1 - The development and validation of the Smell-Qx questionnaire, based on a systematic review of the literature and the COMET initiative on the development of core outcome sets for clinical trials in olfactory disorders

AU - Lechner, Matt

AU - Fjaeldstad, Alexander

AU - Rehman, Umar

AU - Liu, Jacklyn

AU - Boniface, David

AU - Boardman, Jim

AU - Boak, Duncan

AU - Altundag, Aytug

AU - Frasnelli, Johannes

AU - Gane, Simon

AU - Holbrook, Eric

AU - Hsieh, Julien

AU - Huart, Caroline

AU - Konstantinidis, Iordanis

AU - Landis, Basile N.

AU - Lund, Valerie J.

AU - Macchi, Alberto

AU - Mori, Eri

AU - Mueller, Christian

AU - Mullol, Joaquim

AU - Negoias, Simona

AU - Patel, Zara M.

AU - Pinto, Jayant M.

AU - Poletti, Sophia

AU - Ramakrishnan, Vijay

AU - Rombaux, Philippe

AU - Vodicka, Jan

AU - Welge-Luessen, Antje

AU - Whitcroft, Katherine L.

AU - Yan, Carol

AU - Philpott, Carl

AU - Hummel, Thomas

N1 - Data Availability Statement: The data that support the findings of this study are available from the corresponding author upon reasonable request. Funding: The authors received no specific funding for this work.

PY - 2025/5/9

Y1 - 2025/5/9

N2 - Background: Olfactory dysfunction affects up to 22% of the population. Accurate assessment is vital for diagnosis and tracking outcomes, often using patient-reported outcome measures (PROMs). Aims: We aimed to develop and validate a novel questionnaire for assessing olfactory and gustatory dysfunction. Methods: A systematic review identified existing smell and taste questionnaires, followed by item generation and selection. After two Delphi cycles and consultation with a large panel of smell and taste experts, the Smell-Qx questionnaire was developed. A validation study recruited patients from smell and taste clinics (cases) and general ENT clinics (controls) to complete the Smell-Qx. Additionally, patients with smell and taste disorders underwent psychophysical testing using Sniffin' Stick Threshold, Discrimination, and Identification (TDI) tests. Results: The Smell-Qx is an 11-domain instrument, with five core domains used for total score calculation and six history/quality-of-life domains for obtaining a comprehensive history. The validation study recruited 60 participants (32 patients with smell/taste disorders and 28 controls). Items showed acceptable to significant internal consistency (Cronbach's α: 0.64?0.97) and test-retest reliability (ICC: 0.65?0.99, p < 0.001). The Smell-Qx was effective at distinguishing patients with smell and taste disorders from controls (t = 9.99, df = 58, p < 0.0001). Concurrent criterion validity was good with overall SATD-related quality of life (r = 0.43, p = 0.015), as well as with the smell loss domain and overall smell TDI scores (r = ?0.54, p = 0.011). Conclusion: The Smell-Qx is a reliable and valid PROM for assessing olfactory and self-reported gustatory disorders, capturing symptom severity and quality-of-life impact. It can integrate into a multi-modal assessment approach alongside psychophysical testing.

AB - Background: Olfactory dysfunction affects up to 22% of the population. Accurate assessment is vital for diagnosis and tracking outcomes, often using patient-reported outcome measures (PROMs). Aims: We aimed to develop and validate a novel questionnaire for assessing olfactory and gustatory dysfunction. Methods: A systematic review identified existing smell and taste questionnaires, followed by item generation and selection. After two Delphi cycles and consultation with a large panel of smell and taste experts, the Smell-Qx questionnaire was developed. A validation study recruited patients from smell and taste clinics (cases) and general ENT clinics (controls) to complete the Smell-Qx. Additionally, patients with smell and taste disorders underwent psychophysical testing using Sniffin' Stick Threshold, Discrimination, and Identification (TDI) tests. Results: The Smell-Qx is an 11-domain instrument, with five core domains used for total score calculation and six history/quality-of-life domains for obtaining a comprehensive history. The validation study recruited 60 participants (32 patients with smell/taste disorders and 28 controls). Items showed acceptable to significant internal consistency (Cronbach's α: 0.64?0.97) and test-retest reliability (ICC: 0.65?0.99, p < 0.001). The Smell-Qx was effective at distinguishing patients with smell and taste disorders from controls (t = 9.99, df = 58, p < 0.0001). Concurrent criterion validity was good with overall SATD-related quality of life (r = 0.43, p = 0.015), as well as with the smell loss domain and overall smell TDI scores (r = ?0.54, p = 0.011). Conclusion: The Smell-Qx is a reliable and valid PROM for assessing olfactory and self-reported gustatory disorders, capturing symptom severity and quality-of-life impact. It can integrate into a multi-modal assessment approach alongside psychophysical testing.

KW - gustatory dysfunction

KW - olfactory dysfunction

KW - patient-reported outcome measures

UR - http://www.scopus.com/inward/record.url?scp=105004691266&partnerID=8YFLogxK

U2 - 10.1002/alr.23604

DO - 10.1002/alr.23604

M3 - Article

SN - 2042-6976

JO - International Forum of Allergy & Rhinology

JF - International Forum of Allergy & Rhinology

M1 - e23604

ER -

Lechner M, Fjaeldstad A, Rehman U, Liu J, Boniface D, Boardman J et al. The development and validation of the Smell-Qx questionnaire, based on a systematic review of the literature and the COMET initiative on the development of core outcome sets for clinical trials in olfactory disorders. International Forum of Allergy & Rhinology. 2025 May 9;e23604. Epub 2025 May 9. doi: 10.1002/alr.23604

The development and validation of the Smell-Qx questionnaire, based on a systematic review of the literature and the COMET initiative on the development of core outcome sets for clinical trials in olfactory disorders

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Keywords

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