Covid19 Related Anosmia and AguesiaPhase 3NCT04830943
Cerebrolycin for Treatment of Covid-related Anosmia and Ageusia
A Phase 3 study testing Cerebrolysin in people with Covid19 Related Anosmia and Aguesia, run by Assiut University at 1 site in Egypt.
Trial summary
The loss of smell and taste is a prominent symptom of COVID-19. Studies found that patterns of smell loss due to Covid-19 infection differ from that of other respiratory viruses being much more profound in the Covid-19 patents and did not associate with runny, congested, or blocked-up nose. Read more about this study
- Who is it for?
- Ages 20 to 50 years
- Conditions the study is for
- Covid19 Related Anosmia and Aguesia
- What is being tested?
- Cerebrolysin
- Type of treatment
- Injection or infusion
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 250 participants
- Where
- 1 siteEgypt
- Study dates
- 1 Aug 2020to 30 Oct 2022
- Phase
- Phase 3
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 20 to 50 years
- All sexes
- No healthy volunteers
- Adult
Who may be able to join
- A random sample of at least 250 adults with sudden hyposmia/anosmia and/or hypoageusia/ageusia during COVID-19 pandemics and experienced persistent olfactory and/or gustatory manifestations after recovery from other acute viral manifestations.
- compliance for drug intervention (group 1) or olfactory training (group 2) for at least 8 weeks.
Who cannot join
- Prior neurologic, medical or psychiatric disease.
- Other known infection at onset
- Nasal congestion
- Nasal polyps
- Surgery or head trauma or radiation for head and neck cancers as may result in injury to the nerves that control smell
- Exposure to toxic chemicals (such as pesticides and solvents)
Trial locations and contacts
1 site in 1 country.
About this study
Official title: The Effectiveness of Cerebrolycin, a Multi-modal Neurotrophic Factor, for Treatment of Post-covid-19 Persistent Olfactory, Gustatory and Trigeminal Chemosensory Dysfunctions: A Pilot Study
The loss of smell and taste is a prominent symptom of COVID-19. Studies found that patterns of smell loss due to Covid-19 infection differ from that of other respiratory viruses being much more profound in the Covid-19 patents and did not associate with runny, congested, or blocked-up nose. The researchers suggest that smell and taste testing can be used for fast COVID-19 screening. Studies found that the Covid-19 virus has similarities with severe acute respiratory syndrome coronavirus (SARS-CoV), which has been reported to enter the brain, via smell receptors in the nose. The sudden onset and relatively fast recovery in some patients suggest that COVID-19 anosmia is not caused by damage to the central nervous system but rather by the loss of smell information before it gets to the brain (smell receptors). They also found that it has different behavior from other respiratory viruses as it causes over-reaction of the immune system (or a cytokine storm). Trials to treat post-COVID anosmia using local steroid applications, sniffing of strong odors or scents or use of different vitamins (for several weeks to months) did not provide rapid, satisfactory or even significant recovery of olfactory dysfunction. Fortunately, the olfactory neurons can regenerate, however, studies reported variable prognoses, some patients recovered within weeks which others may have persistent deficits for months or even a year. In this study, the researchers hypothesize that cerebrolysin, a drug of neurotrophic and neuroprotective properties, can be used to treat patients with persistent post-COVID anosmia or ageusia or promote functional recovery of smell and taste deficits.
Read the detailed description
Initial descriptions of the COVID-19 pandemic have focused on its acute severe manifestations. After several months, data have emerged about the mild disease and Post-COVID syndrome. The diminished senses of smell (or hyposmia/anosmia) and taste (or hypogeusia/ageusia) have been commonly reported in the pandemic. Hyposmia/anosmia and hypogeusia/ageusia have also been reported with previous coronaviruses. In late March, the professional society of Ear, Nose, and Throat (ENT) in the United Kingdom (UK) published an advisory on evidence from South Korea, China, and Italy that significant number of COVID-19 positive patients also lost smell and/or taste. Based also on several other reports which reported that 66-88% of patients have lost smell and/or taste due to COVID-19 infection, the American Academy of Otolaryngology-Head and Neck Surgery and World Health Organization (WHO) have added anosmia and ageusia to the list of symptoms of COVID-19. The prognosis of such deficits seems variable. Some reported recovery within few weeks; while many reported persistence of deficits for several months or even more than a year after the onset of the condition. Furthermore, some patients developed respiratory symptoms later after anosmia while others remained asymptomatic. The exact mechanisms for these deficits are still under research. In animal models, the investigators found that coronaviruses could impair the olfactory neuroepithelium through the expression of angiotensin-converting enzyme type 2 (ACE2) in the sustentacular cells or damage the receptors. Treatment trials of post-COVID anosmia included the application of nasal corticosteroids, regular sniffing of different odors and strong scents, and treatment with antioxidants and vitamins or interventions as olfactory training. However, none was therapeutically effective. Previous preclinical and clinical studies have shown that treatment with neurotrophic polypeptides can promote neurological recovery for many neurodegenerative and acquired nervous system diseases due to different causes. As the olfactory neurons are capable of regeneration, the researchers propose that treating patients with prolonged post-COVID anosmia or ageusia using cerebrolysin, a drug of neurotrophic and neuroprotective properties may promote recovery of olfactory and gustatory dysfunctions. Cerebrolysin is a mixture of peptides purified from brains, including (and not limited to) brain-derived neurotrophic factor (BDNF), glial cell line-derived neurotrophic factor (GDNF), nerve growth factor (NGF), and ciliary neurotrophic factor (CNTF).
- Conditions
- Covid19 Related Anosmia and Aguesia
- Being tested
- Cerebrolysin
- Keywords
- COVID-19, ; anosmia, ; ageusia, ; cerebrolysin
- Medical subject headings
- COVID-19, Anosmia, Ageusia
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
CerebrolysinDrug
Also called Neurotropic factors
Cerebrolysin will be prescribed in a dose of 5 ml ampoule once daily through intramuscular injection (1ml contains 215.2 mg cerebrolysin) for five times per week, for a total of 40 treatments (for 8 weeks), after which the cycle was individually repeated according to the response of the patient to therapy for a maximum of 24 weeks
| Study group | Role | What they receive |
|---|---|---|
| Olfactory and gustatory disorders after covid 19 infection (n = 150) | Experimental | Cerebrolysin Dose:5 ml ampoule (1ml contains 215.2 mg cerebrolysin) once daily through intramuscular injection five times per week, for a total of 40 treatments (for at least 8 weeks after presentation), after which the cycle was repeated again according to the each patient response to therapy for a maximum of 24 weeks. Receives: Drug: Cerebrolysin |
| control group (n = 100) | No intervention | no drug intervention, just olfactory training using at least 4 strong odors to smell twice daily for at least 15 minutes (every time), for at least 8 weeks after presentation. |
What is being measured
The primary outcome is the main question the study is designed to answer.
The smell and taste questionnaire component of the National Health and Nutrition Examination Survey (NHNES). And the modified Arabic translated and validated sniffin' sticks odor identification test was used for objective olfactory evaluations.
The NHNES questions have been selected to characterize the variation, timing and associated-symptoms of both olfactory and gustatory systems.
Measured: The subject smell and taste sensations at baseline (presentation)
objective testings: sniffen's odor, taste and flavor identification testing
For quantitative assessment of smell, we used 16 odors familiar to Egyptians For quantitative assessment of taste loss, we used sugar (sweet), salt (salty), lemon (sour), old rumi cheese chips (umami) and coffee (bitter), the five basic tastants.
For quantitative assessment of flavor, we used 16 recipes familiar for Egyptians.
Measured: at presentation (baseline)
Secondary outcomes (3)
The Globas Rating for smell (GRS)
GRS is a single-item, global rating that asks the patient to rate his current sense of smell as follow: excellent, very good, good, fair, poor or absent
Measured: 8 weeks, 12 weeks, 16 weeks, 18 weeks and 24 weeks
The Globas Rating for taste (GRT)
GRT is a single-item, global rating that asks the patient to rate his current sense of taste as follow: excellent, very good, good, fair, poor or absent
Measured: 8 weeks, 12 weeks, 18 weeks and 24 weeks
objective testings: sniffen's odor, taste and flavor identification testing
For quantitative assessment of smell, we used 16 odors familiar to Egyptians For quantitative assessment of taste loss, we used sugar (sweet), salt (salty), lemon (sour), old rumi cheese chips (umami) and coffee (bitter), the five basic tastants.
For quantitative assessment of flavor, we used 16 recipes familiar for Egyptians.
Measured: at 8, 12, 16, 18 and 24 weeks after intial evaluation at baseline
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted5 Apr 2021
- Study start1 Aug 2020
- Primary completion30 Sep 2021
- Study completion30 Oct 2022
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (5)Papers the sponsor has linked to this study.
- Other trials for Covid19 Related Anosmia and AguesiaStudies of the same condition, open and under way.
- More trials run by Assiut UniversityThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 3
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Enrolment
- 250 participants (actual)
Sponsor and investigators
- Lead sponsor
- Assiut University
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Sherifa Ahmed Hamed, Assiut University
- Investigators
- Sherifa A Hamed, M.D., Principal investigator, Assiut University, Faculty of Medicine
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT04830943
- Sponsor's protocol ID
- COVID-NGF/AUH_SAH/2020
- Status last verified
- Dec 2022
- First submitted
- 24 Dec 2020
- Last updated
- 3 Jan 2023
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Publications
Chachkhiani D, Soliman MY, Barua D, Isakadze M, Villemarette-Pittman NR, Devier DJ, Lovera JF. Neurological complications in a predominantly African American sample of COVID-19 predict worse outcomes during hospitalization. Clin Neurol Neurosurg. 2020 Oct;197:106173. doi: 10.1016/j.clineuro.2020.106173. Epub 2020 Aug 25.
PubMed 32877769Shrestha GS, Khanal S, Sharma S, Nepal G. COVID-19: Current Understanding of Pathophysiology. J Nepal Health Res Counc. 2020 Nov 13;18(3):351-359. doi: 10.33314/jnhrc.v18i3.3028.
PubMed 33210623Veinbergs I, Mante M, Mallory M, Masliah E. Neurotrophic effects of Cerebrolysin in animal models of excitotoxicity. J Neural Transm Suppl. 2000;59:273-80. doi: 10.1007/978-3-7091-6781-6_29.
PubMed 10961439Lechien JR, Chiesa-Estomba CM, De Siati DR, Horoi M, Le Bon SD, Rodriguez A, Dequanter D, Blecic S, El Afia F, Distinguin L, Chekkoury-Idrissi Y, Hans S, Delgado IL, Calvo-Henriquez C, Lavigne P, Falanga C, Barillari MR, Cammaroto G, Khalife M, Leich P, Souchay C, Rossi C, Journe F, Hsieh J, Edjlali M, Carlier R, Ris L, Lovato A, De Filippis C, Coppee F, Fakhry N, Ayad T, Saussez S. Olfactory and gustatory dysfunctions as a clinical presentation of mild-to-moderate forms of the coronavirus disease (COVID-19): a multicenter European study. Eur Arch Otorhinolaryngol. 2020 Aug;277(8):2251-2261. doi: 10.1007/s00405-020-05965-1. Epub 2020 Apr 6.
PubMed 32253535Hamed SA, Ahmed MAA. The effectiveness of cerebrolysin, a multi-modal neurotrophic factor, for treatment of post-covid-19 persistent olfactory, gustatory and trigeminal chemosensory dysfunctions: a randomized clinical trial. Expert Rev Clin Pharmacol. 2023 Jul-Dec;16(12):1261-1276. doi: 10.1080/17512433.2023.2282715. Epub 2023 Dec 9.
PubMed 37950370
Study at a glance
From the registry record, last updated by the sponsor on 3 Jan 2023. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- The Effectiveness of Cerebrolycin, a Multi-modal Neurotrophic Factor, for Treatment of Post-covid-19 Persistent Olfactory, Gustatory and Trigeminal Chemosensory Dysfunctions: A Pilot Study
- ClinicalTrials.gov ID
- NCT04830943
- Acronym / sponsor ID
- COVID-NGF/AUH_SAH/2020
- Conditions
- Covid19 Related Anosmia and Aguesia
- Keywords
- COVID-19, ; anosmia, ; ageusia, ; cerebrolysin
- Phase
- Phase 3
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 250 participants (actual)
- Lead sponsor
- Assiut UniversityUniversity, hospital or other
- Study start
- 1 Aug 2020 (actual)
- Primary completion
- 30 Sep 2021 (actual)
- Study completion
- 30 Oct 2022 (actual)
- First posted
- 5 Apr 2021 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The loss of smell and taste is a prominent symptom of COVID-19. Studies found that patterns of smell loss due to Covid-19 infection differ from that of other respiratory viruses being much more profound in the Covid-19 patents and did not associate with runny, congested, or blocked-up nose. The researchers suggest that smell and taste testing can be used for fast COVID-19 screening. Studies found that the Covid-19 virus has similarities with severe acute respiratory syndrome coronavirus (SARS-CoV), which has been reported to enter the brain, via smell receptors in the nose. The sudden onset and relatively fast recovery in some patients suggest that COVID-19 anosmia is not caused by damage to the central nervous system but rather by the loss of smell information before it gets to the brain (smell receptors). They also found that it has different behavior from other respiratory viruses as it causes over-reaction of the immune system (or a cytokine storm). Trials to treat post-COVID anosmia using local steroid applications, sniffing of strong odors or scents or use of different vitamins (for several weeks to months) did not provide rapid, satisfactory or even significant recovery of olfactory dysfunction. Fortunately, the olfactory neurons can regenerate, however, studies reported variable prognoses, some patients recovered within weeks which others may have persistent deficits for months or even a year. In this study, the researchers hypothesize that cerebrolysin, a drug of neurotrophic and neuroprotective properties, can be used to treat patients with persistent post-COVID anosmia or ageusia or promote functional recovery of smell and taste deficits.
Detailed description
Initial descriptions of the COVID-19 pandemic have focused on its acute severe manifestations. After several months, data have emerged about the mild disease and Post-COVID syndrome. The diminished senses of smell (or hyposmia/anosmia) and taste (or hypogeusia/ageusia) have been commonly reported in the pandemic. Hyposmia/anosmia and hypogeusia/ageusia have also been reported with previous coronaviruses. In late March, the professional society of Ear, Nose, and Throat (ENT) in the United Kingdom (UK) published an advisory on evidence from South Korea, China, and Italy that significant number of COVID-19 positive patients also lost smell and/or taste. Based also on several other reports which reported that 66-88% of patients have lost smell and/or taste due to COVID-19 infection, the American Academy of Otolaryngology-Head and Neck Surgery and World Health Organization (WHO) have added anosmia and ageusia to the list of symptoms of COVID-19. The prognosis of such deficits seems variable. Some reported recovery within few weeks; while many reported persistence of deficits for several months or even more than a year after the onset of the condition. Furthermore, some patients developed respiratory symptoms later after anosmia while others remained asymptomatic. The exact mechanisms for these deficits are still under research. In animal models, the investigators found that coronaviruses could impair the olfactory neuroepithelium through the expression of angiotensin-converting enzyme type 2 (ACE2) in the sustentacular cells or damage the receptors. Treatment trials of post-COVID anosmia included the application of nasal corticosteroids, regular sniffing of different odors and strong scents, and treatment with antioxidants and vitamins or interventions as olfactory training. However, none was therapeutically effective. Previous preclinical and clinical studies have shown that treatment with neurotrophic polypeptides can promote neurological recovery for many neurodegenerative and acquired nervous system diseases due to different causes. As the olfactory neurons are capable of regeneration, the researchers propose that treating patients with prolonged post-COVID anosmia or ageusia using cerebrolysin, a drug of neurotrophic and neuroprotective properties may promote recovery of olfactory and gustatory dysfunctions. Cerebrolysin is a mixture of peptides purified from brains, including (and not limited to) brain-derived neurotrophic factor (BDNF), glial cell line-derived neurotrophic factor (GDNF), nerve growth factor (NGF), and ciliary neurotrophic factor (CNTF).
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Olfactory and gustatory disorders after covid 19 infection (n = 150) | Experimental | Drug: CerebrolysinCerebrolysin Dose:5 ml ampoule (1ml contains 215.2 mg cerebrolysin) once daily through intramuscular injection five times per week, for a total of 40 treatments (for at least 8 weeks after presentation), after which the cycle was repeated again according to the each patient response to therapy for a maximum of 24 weeks. |
| control group (n = 100) | No intervention | –no drug intervention, just olfactory training using at least 4 strong odors to smell twice daily for at least 15 minutes (every time), for at least 8 weeks after presentation. |
Who may qualify
- Ages
- 20 to 50 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult
Key inclusion criteria (2 listed)
- A random sample of at least 250 adults with sudden hyposmia/anosmia and/or hypoageusia/ageusia during COVID-19 pandemics and experienced persistent olfactory and/or gustatory manifestations after recovery from other acute viral manifestations.
- compliance for drug intervention (group 1) or olfactory training (group 2) for at least 8 weeks.
Key exclusion criteria (6 listed)
- Prior neurologic, medical or psychiatric disease.
- Other known infection at onset
- Nasal congestion
- Nasal polyps
- Surgery or head trauma or radiation for head and neck cancers as may result in injury to the nerves that control smell
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| CerebrolysinAlso: Neurotropic factorsCerebrolysin will be prescribed in a dose of 5 ml ampoule once daily through intramuscular injection (1ml contains 215.2 mg cerebrolysin) for five times per week, for a total of 40 treatments (for 8 weeks), after which the cycle was individually repeated according to the response of the patient to therapy for a maximum of 24 weeks | Drug | Olfactory and gustatory disorders after covid 19 infection (n = 150) |
Primary outcome
The smell and taste questionnaire component of the National Health and Nutrition Examination Survey (NHNES). And the modified Arabic translated and validated sniffin' sticks odor identification test was used for objective olfactory evaluations.
Time frame: The subject smell and taste sensations at baseline (presentation)
The NHNES questions have been selected to characterize the variation, timing and associated-symptoms of both olfactory and gustatory systems.
objective testings: sniffen's odor, taste and flavor identification testing
Time frame: at presentation (baseline)
For quantitative assessment of smell, we used 16 odors familiar to Egyptians For quantitative assessment of taste loss, we used sugar (sweet), salt (salty), lemon (sour), old rumi cheese chips (umami) and coffee (bitter), the five basic tastants. For quantitative assessment of flavor, we used 16 recipes familiar for Egyptians.
3 secondary outcomes
The Globas Rating for smell (GRS)
Time frame: 8 weeks, 12 weeks, 16 weeks, 18 weeks and 24 weeks
The Globas Rating for taste (GRT)
Time frame: 8 weeks, 12 weeks, 18 weeks and 24 weeks
objective testings: sniffen's odor, taste and flavor identification testing
Time frame: at 8, 12, 16, 18 and 24 weeks after intial evaluation at baseline
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 3 Jan 2023.
- Background: PubMed 32877769Chachkhiani D, Soliman MY, Barua D, Isakadze M, Villemarette-Pittman NR, Devier DJ, Lovera JF. Neurological complications in a predominantly African American sample of COVID-19 predict worse outcomes during hospitalization. Clin Neurol Neurosurg. 2020 Oct;197:106173. doi: 10.1016/j.clineuro.2020.106173. Epub 2020 Aug 25.
- Background: PubMed 33210623Shrestha GS, Khanal S, Sharma S, Nepal G. COVID-19: Current Understanding of Pathophysiology. J Nepal Health Res Counc. 2020 Nov 13;18(3):351-359. doi: 10.33314/jnhrc.v18i3.3028.
- Background: PubMed 10961439Veinbergs I, Mante M, Mallory M, Masliah E. Neurotrophic effects of Cerebrolysin in animal models of excitotoxicity. J Neural Transm Suppl. 2000;59:273-80. doi: 10.1007/978-3-7091-6781-6_29.
- Results publication: PubMed 32253535Lechien JR, Chiesa-Estomba CM, De Siati DR, Horoi M, Le Bon SD, Rodriguez A, Dequanter D, Blecic S, El Afia F, Distinguin L, Chekkoury-Idrissi Y, Hans S, Delgado IL, Calvo-Henriquez C, Lavigne P, Falanga C, Barillari MR, Cammaroto G, Khalife M, Leich P, Souchay C, Rossi C, Journe F, Hsieh J, Edjlali M, Carlier R, Ris L, Lovato A, De Filippis C, Coppee F, Fakhry N, Ayad T, Saussez S. Olfactory and gustatory dysfunctions as a clinical presentation of mild-to-moderate forms of the coronavirus disease (COVID-19): a multicenter European study. Eur Arch Otorhinolaryngol. 2020 Aug;277(8):2251-2261. doi: 10.1007/s00405-020-05965-1. Epub 2020 Apr 6.
- Derived from this study: PubMed 37950370Hamed SA, Ahmed MAA. The effectiveness of cerebrolysin, a multi-modal neurotrophic factor, for treatment of post-covid-19 persistent olfactory, gustatory and trigeminal chemosensory dysfunctions: a randomized clinical trial. Expert Rev Clin Pharmacol. 2023 Jul-Dec;16(12):1261-1276. doi: 10.1080/17512433.2023.2282715. Epub 2023 Dec 9.
- Individual participant dataSharing planned: No
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Sherifa A Hamed, M.D. principal investigator
Assiut University, Faculty of Medicine
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 3 study testing Cerebrolysin in people with Covid19 Related Anosmia and Aguesia, run by Assiut University at 1 site in Egypt.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 2 inclusion and 6 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 3 Jan 2023. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Egypt. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 3 studies compare the treatment with the current standard treatment or a placebo in a large group, to confirm how well it works and watch for side effects.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
The smell and taste questionnaire component of the National Health and Nutrition Examination Survey (NHNES). And the modified Arabic translated and validated sniffin' sticks odor identification test was used for objective olfactory evaluations. (time frame: The subject smell and taste sensations at baseline (presentation)). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT04830943, which also lists 5 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 3 Jan 2023.