Title: The prevention and treatment of persisting olfactory dysfunction following COVID-19 infection; a suite of Cochrane living systematic reviews
Funder: Department of Health and Social Care

Abstract: The loss of the sense of smell is a frequent symptom of COVID-19 infection. The loss can be partial or complete. For a significant proportion of patients the loss is only temporary and their sense of smell recovers relatively quickly. For others the problem can continue and it is a terrible thing to suffer from. It can have a major impact on quality of life because eating and drinking is much less pleasurable. Losing your sense of smell has a big effect on what food ‘tastes’ like as the two sense are closely linked._x000D_ _x000D_ This project proposes a set of high-quality evidence reviews (Cochrane reviews) that look at the prevention and treatment of this condition. The key questions are these: Are there any treatments that can help a patient recover more quickly, or recover completely when they might otherwise not do so? Or is there something that patients with COVID-19 could be given, even before they lose their sense of smell, that might prevent this happening? The type of evidence review that we are proposing looks to see if any trials have been done on treatments for this condition. It assesses how good those trials are, and brings together the results from all the trials that look at similar treatments, all with the aim of trying to decide: do the treatments work, do they cause any harm and therefore might they be useful in practice?_x000D_ _x000D_ When people do trials to assess whether a treatment works or not, there are various things they might measure. The first part of our project will involve talking to patients who have lost their sense of smell and asking them what things they think it is important to measure in such trials. _x000D_ _x000D_ This work will be undertaken by the team at Cochrane ENT using ‘gold standard’ methods. Cochrane ENT has experience in doing this in a number of other clinical areas. _x000D_ _x000D_ Rather than doing this simply as a 'one off' project in late 2020, our proposal is to keep repeating the process of looking for trials and adding the results to the Cochrane reviews over the next two years. This means doing so-called 'living' systematic reviews. This is likely to be important because at the moment, since COVID-19 is such a new disease and not many trials have been completed, there may not be any answers in our reviews. As time goes on, and more trials are done (perhaps even looking at more and different treatments), we will include the results of those trials in our Cochrane reviews.

Lay abstract: This project proposes a suite of Cochrane systematic reviews on the prevention and treatment of olfactory dysfunction due to COVID-19. It is addressed to the Evidence Synthesis Programme._x000D_ _x000D_ Olfactory dysfunction is a cardinal symptom of COVID-19 infection. This usually takes the form of partial or complete loss of olfactory function (hyposmia and anosmia respectively). For a significant proportion of patients this is only a transient phenomenon, and they recover a normal sense of smell relatively quickly. For others the problem can persist. It is a debilitating condition with a major impact on quality of life. _x000D_ _x000D_ The primary aims and objectives are:_x000D_ _x000D_ 1. To identify those interventions that have been used, or proposed, to prevent or treat olfactory dysfunction due to COVID-19 infection._x000D_ 2. Working with patients and other stakeholders to identify a set of prioritised outcomes for use in systematic reviews evaluating the effectiveness of those treatments. _x000D_ 3. To publish - rapidly - a suite of Cochrane systematic reviews evaluating the effectiveness of these treatments, and any adverse effects, using the prioritised outcomes._x000D_ 4. Anticipating limited data at this stage of the pandemic, to maintain these reviews as ‘living’ systematic reviews for a period of at least 24 months._x000D_ 5. To inform practice (if effective treatments are identified) and research (if further trials are necessary)._x000D_ _x000D_ This work will be undertaken by an experienced team at Cochrane ENT using standard Cochrane methods. The identification of interventions and outcomes, and in particular the critical engagement with patients to do the latter, builds on experience of the Group in doing this in a number of other clinical areas. The Group will also use its experience of doing formal and informal 'living' systematic reviews._x000D_ _x000D_ The key output is a suite of living Cochrane systematic reviews updated regularly over the next two years (the suite will comprise at least two reviews, as trials evaluating two interventions have already been identified). Secondary outputs include a prioritised list of patient-focused outcomes for systematic reviews of trials in patients with olfactory dysfunction.

Research activity codes: 6.1 PHARMACEUTICALS;6.4 SURGERY
Health categories: INFECTION