Evidence map›Paper›PMID 39740091›Full record

Trial reportInternational forum of allergy & rhinology2025

Long-term Outcomes of PRP Injections for Post-viral Olfactory Loss: A Prospective Cohort Study.

Maxime Fieux, Bruna R Castro, Sophie S Jang, Carol H Yan, Zara M Patel

Abstract readRandomized Controlled Trial
PubMed Full text at PMC Publisher
In one paragraph

Trial report in International forum of allergy & rhinology, 2025. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 6 papers, 1 of them a synthesis that pooled it.

0numbers the graph read from it
0cells of the map it votes in
6citing papers in PubMed, 1 pooled it
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

6 citing papers in PubMed, 1 synthesis or guideline pooled it.

  1. Navigating the efficacy, safety and outcome of intranasal platelet-rich plasma for persistent olfactory loss: a systematic review and meta-analysis.European archives of oto-rhino-laryngology : official journal of the European Federation of Oto-Rhino-Laryngological Societies (EUFOS) : affiliated with the German Society for Oto-Rhino-Laryngology - Head and Neck Surgery · 2026
    Pooled it
  2. Article
  3. Article
  4. Article
  5. Review
  6. Validity and Reliability of the French Olfactory Disorders Questionnaire-10.Journal of otolaryngology - head & neck surgery = Le Journal d'oto-rhino-laryngologie et de chirurgie cervico-faciale
    Article
4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

5 authors.

Maxime FieuxDepartment of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Stanford, California, USA.ORCID 0000-0001-8317-2286
Bruna R CastroDepartment of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Stanford, California, USA.
Sophie S JangDepartment of Otolaryngology-Head and Neck Surgery, San Diego School of Medicine, University of California, La Jolla, California, USA.
Carol H YanDepartment of Otolaryngology-Head and Neck Surgery, San Diego School of Medicine, University of California, La Jolla, California, USA.
Zara M PatelDepartment of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Stanford, California, USA.ORCID 0000-0003-2072-982X

Funding

Elucidating Olfactory Epithelial Anti-Viral Responses in Persistent Post-Viral Olfactory DysfunctionK08DC019956 · NIDCD · UNIVERSITY OF CALIFORNIA, SAN DIEGO · PI Carol H Yan · 2022 to 2026
$959k
Foundation Edmond RoudnitskaFoundation of the Hospices Civil de Lyon fellowshipFrance-Stanford CenterNIDCD NIH HHS K08 DC019956NIH/NIDCD K08DC019956Philippe Foundation
6 · The paper itself

Abstract

backgroundPlatelet-rich plasma (PRP) injections have previously been shown to benefit coronavirus disease 2019 (COVID-19)-induced smell loss. It is unknown if that benefit is stable over time. The aim of this study was to assess outcomes at 1-year post-intervention.

methodsProspective cohort study. Sixteen patients (10 PRP and six placebo) from the original PRP randomized placebo-controlled clinical trial, and a further 16 patients from smell clinic who were a year out from initial treatment (six PRP patients and 10 non-PRP) were enrolled. University of Pennsylvania Smell Identification Tests (UPSITs) and visual analog scale (VAS) subjective scores were compared to initial scores.

resultsThere was no difference between groups with respect to age, gender, race, duration of smell loss prior to intervention, smoking or diabetes status, Charlson comorbidity index, presence of phantosmia or parosmia, or baseline UPSIT score. The PRP group had a significantly higher change in UPSIT score at 1 year (p = 0.001), a higher number of patients who met the minimal clinically important difference for the UPSIT (87.5% vs. 31.2%, p = 0.004), and a significantly greater change in VAS at 1 year (p = 0.001), compared to those who did not receive injections. On multivariate logistic regression analysis, no factors appeared to have a significant effect on these findings.

conclusionPRP injections into the olfactory cleft now have long-term data suggesting benefit in both subjective and psychophysical measures of smell, and improvements in both realms at 1 year are significantly higher than in those who do not receive the injections.

Indexed as

AnosmiaCOVID-19Olfaction DisordersPlatelet-Rich PlasmaAdultAgedFemaleHumansMaleMiddle AgedProspective StudiesSARS-CoV-2SmellTreatment Outcomeanosmiahyposmialong‐term effectolfaction disordersplatelet‐rich plasmasmell disorderssmell loss

Identifiers

PMID39740091
PMCPMC12857808

What OpenQuestion holds

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Registered trials

None linked

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.