Olfactory dysfunction in SARS-CoV-2 infection: 12 month trajectory of psychophysical tests

Abstract

Aim: To report olfactory dysfunction (OD) as measured by psychophysical testing in the post-acute COVID-19 patient over a 12-month period; to correlate this with patient-reported quality of life (QOL) outcomes. Methods: In this multi-centre UK prospective cohort, adults with confirmed COVID-19 completed the University of Pennsylvania Smell Identification Test (UPSIT), the validated Sinonasal Outcome Test-22 (SNOT-22) and the English Questionnaire of Olfactory Disorders (eQOD) at baseline (median 3 months after infection), then at 1, 3, 6, 9 and 12 months after baseline. Results: Seventy-eight (78) patients completed baseline testing and 55 completed testing at 12 months. At baseline, OD was present in 70/78 participants (89.7%; 95% CI 81.0–94.7%). At 12 months, 50/55 participants had persisting OD (90.9%; 95% CI 80.4–96.1%). Mean UPSIT scores were 26.8 ± 6.3 at baseline and 27.4 ± 6.3 at 12 months, indicating minimal change. Symptom burden and disease-specific QOL improved over 12 months with mean SNOT-22 test scores going from 29.5 ± 21.8 to 22.2 ± 18.6, p < 0.01; Mean eQOD scores from 59.8 ± 31.0 to 48.3 ± 32.6, p = 0.53, though neither trends were statistically significant. Conclusions: Olfactory dysfunction frequently persisted one year beyond post-acute COVID-19 diagnosis, whereas a trend of improvement on quality of life measures were observed. Combined use of psychophysical testing and QOL questionnaires is supported for follow-up and patient counselling.