Cantone E, D'Ascanio L, De Luca P, Roccamatisi D, La La Mantia I, Brenner MJ, Di Stadio A. Persistent COVID-19 parosmia and olfactory loss post olfactory training: randomized clinical trial comparing central and peripheral-acting therapeutics.
Eur Arch Otorhinolaryngol 2024;
281:3671-3678. [PMID:
38492007 PMCID:
PMC11211159 DOI:
10.1007/s00405-024-08548-6]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Accepted: 02/12/2024] [Indexed: 03/18/2024]
Abstract
PURPOSE
Although COVID-19 anosmia is often transient, patients with persistent olfactory dysfunction (pOD) can experience refractory parosmia and diminished smell. This study evaluated four putative therapies for parosmia in patients with chronic COVID-19 olfactory impairment.
METHODS
After screening nasal endoscopy, 85 patients (49 female, 58%) with pOD and treatment-refractory parosmia were randomized to: (1) ultramicronized palmitoylethanolamide and luteolin + olfactory training (OT) (umPEALUT group, n = 17), (2) alpha-lipoic acid + OT (ALA group, n = 21), (3) umPEALUT + ALA + OT (combination group, n = 28), or 4) olfactory training (OT) alone (control group, n = 23). Olfactory function was assessed at baseline (T0) and 6 months (T1) using a parosmia questionnaire and Sniffin' Sticks test of odor threshold, detection, and identification (TDI). Analyses included one-way ANOVA for numeric data and Chi-Square analyses for nominal data on parosmia.
RESULTS
The umPEALUT group had the largest improvement in TDI scores (21.8 ± 9.4 to 29.7 ± 7.5) followed by the combination group (19.6 ± 6.29 to 27.5 ± 2.7), both p < 0.01. The control and ALA groups had no significant change. Patients in the combination and umPEALUT groups had significantly improved TDI scores compared to ALA and control groups (p < 0.001). Rates of parosmia resolution after 6 months were reported at 96% for combination, 65% for control, 53% for umPEALUT and 29% for ALA (p < 0.001). All treatment regimens were well-tolerated.
CONCLUSIONS
umPEALUT and OT, with or without ALA, was associated with improvement in TDI scores and parosmia, whereas OT alone or OT with ALA were associated with little benefit.
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