Mihalis Katotomichelakis

Bio: Mihalis Katotomichelakis is an academic researcher from Democritus University of Thrace. The author has contributed to research in topics: Hyposmia & Anosmia. The author has an hindex of 1, co-authored 1 publications receiving 8 citations.

Smell and Taste Loss Recovery Time in COVID-19 Patients and Disease Severity.

Abstract: A significant proportion of people infected with SARS-CoV-2 report a new onset of smell or taste loss. The duration of the chemosensory impairment and predictive factors of recovery are still unclear. We aimed to investigate the prevalence, temporal course and recovery predictors in patients who suffered from varying disease severity. Consecutive adult patients diagnosed to be infected with SARS-CoV-2 via reverse-transcription–polymerase chain reaction (RT-PCR) at two coronavirus disease-2019 (COVID-19) Reference Hospitals were contacted to complete a survey reporting chemosensory loss, severity, timing and duration, nasal symptoms, smoking, allergic rhinitis, chronic rhinosinusitis, comorbidities and COVID-19 severity. In a cross-sectional study, we contacted 182 patients and 150 responded. Excluding the critically ill patients, 38% reported gustatory and 41% olfactory impairment (74% severe/anosmia). Most of the patients (88%) recovered their sense of smell by two months (median: 11.5 days; IQR: 13.3). For 23%, the olfactory loss lasted longer than a month. There were no significant differences in the prevalence and duration of chemosensory loss between groups of varying COVID-19 severity, and sexes (all p > 0.05). Moderate hyposmia resolved quicker than more severe loss (p = 0.04). Smell and taste loss are highly prevalent in COVID-19. Most patients recover fast, but nearly one out of ten have not recovered in two months.

Prognosis and persistence of smell and taste dysfunction in patients with covid-19: meta-analysis with parametric cure modelling of recovery curves

Abstract: Abstract Objective To clarify in patients with covid-19 the recovery rate of smell and taste, proportion with persistent dysfunction of smell and taste, and prognostic factors associated with recovery of smell and taste. Design Systematic review and meta-analysis. Data sources PubMed, Embase, Scopus, Cochrane Library, and medRxiv from inception to 3 October 2021. Review methods Two blinded reviewers selected observational studies of adults (≥18 years) with covid-19 related dysfunction of smell or taste. Descriptive prognosis studies with time-to-event curves and prognostic association studies of any prognostic factor were included. Data extraction and synthesis Two reviewers extracted data, evaluated study bias using QUIPS, and appraised evidence quality using GRADE, following PRISMA and MOOSE reporting guidelines. Using iterative numerical algorithms, time-to-event individual patient data (IPD) were reconstructed and pooled to retrieve distribution-free summary survival curves, with recovery rates reported at 30 day intervals for participants who remained alive. To estimate the proportion with persistent smell and taste dysfunction, cure fractions from Weibull non-mixture cure models of plateaued survival curves were logit transformed and pooled in a two stage meta-analysis. Conventional aggregate data meta-analysis was performed to explore unadjusted associations of prognostic factors with recovery. Main outcome measures The primary outcomes were the proportions of patients remaining with smell or taste dysfunction. Secondary outcomes were the odds ratios of prognostic variables associated with recovery of smell and taste. Results 18 studies (3699 patients) from 4180 records were included in reconstructed IPD meta-analyses. Risk of bias was low to moderate; conclusions remained unaltered after exclusion of four high risk studies. Evidence quality was moderate to high. Based on parametric cure modelling, persistent self-reported smell and taste dysfunction could develop in an estimated 5.6% (95% confidence interval 2.7% to 11.0%, I2=70%, τ2=0.756, 95% prediction interval 0.7% to 33.5%) and 4.4% (1.2% to 14.6%, I2=67%, τ2=0.684, 95% prediction interval 0.0% to 49.0%) of patients, respectively. Sensitivity analyses suggest these could be underestimates. At 30, 60, 90, and 180 days, respectively, 74.1% (95% confidence interval 64.0% to 81.3%), 85.8% (77.6% to 90.9%), 90.0% (83.3% to 94.0%), and 95.7% (89.5% to 98.3%) of patients recovered their sense of smell (I2=0.0-77.2%, τ2=0.006-0.050) and 78.8% (70.5% to 84.7%), 87.7% (82.0% to 91.6%), 90.3% (83.5% to 94.3%), and 98.0% (92.2% to 95.5%) recovered their sense of taste (range of I2=0.0-72.1%, τ2=0.000-0.015). Women were less likely to recover their sense of smell (odds ratio 0.52, 95% confidence interval 0.37 to 0.72, seven studies, I2=20%, τ2=0.0224) and taste (0.31, 0.13 to 0.72, seven studies, I2=78%, τ2=0.5121) than men, and patients with greater initial severity of dysfunction (0.48, 0.31 to 0.73, five studies, I2=10%, τ2<0.001) or nasal congestion (0.42, 0.18 to 0.97, three studies, I2=0%, τ2<0.001) were less likely to recover their sense of smell. Conclusions A substantial proportion of patients with covid-19 might develop long lasting change in their sense of smell or taste. This could contribute to the growing burden of long covid. Systematic review registration PROSPERO CRD42021283922.

Taste loss as a distinct symptom of COVID-19: a systematic review and meta-analysis.

Abstract: Chemosensory scientists have been skeptical that reports of COVID-19 taste loss are genuine, in part because before COVID-19 taste loss was rare and often confused with smell loss. Therefore, to establish the predicted prevalence rate of taste loss in COVID-19 patients, we conducted a systematic review and meta-analysis of 376 papers published in 2020-2021, with 241 meeting all inclusion criteria. Drawing on previous studies and guided by early meta-analyses, we explored how methodological differences (direct vs. self-report measures) may affect these estimates. We hypothesized that direct measures of taste are at least as sensitive as those obtained by self-report and that the preponderance of evidence confirms taste loss is a symptom of COVID-19. The meta-analysis showed that, among 138,897 COVID-19-positive patients, 39.2% reported taste dysfunction (95% confidence interval: 35.34%-43.12%), and the prevalence estimates were slightly but not significantly higher from studies using direct (n = 18) versus self-report (n = 223) methodologies (Q = 0.57, df = 1, P = 0.45). Generally, males reported lower rates of taste loss than did females, and taste loss was highest among middle-aged adults. Thus, taste loss is likely a bona fide symptom of COVID-19, meriting further research into the most appropriate direct methods to measure it and its underlying mechanisms.

Is loss of smell an early predictor of COVID-19 severity: a systematic review and meta-analysis.

Abstract: Anecdotal evidence suggests that the severity of coronavirus disease of 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is likely to be distinguished by variations in loss of smell (LOS). Thus, we conducted a meta-analysis of 45 articles that include a total of 42,120 COVID-19 patients from 17 different countries to demonstrate that severely ill or hospitalized COVID-19 patients have a lesser chance of experiencing LOS than non-severely ill or non-hospitalized COVID-19 patients (odds ratio = 0.527 [95% CI 0.373-0.744; p < 0.001] and 0.283 [95% CI 0.173-0.462; p < 0.001], respectively). We also proposed a possible mechanism underlying the association of COVID-19 severity with anosmia, which may explain why patients without sense of smell develop severe COVID-19. Variations in LOS according to the severity of COVID-19 is a global phenomenon, with few exceptions. Since severely ill patients have a lower rate of anosmia, patients without anosmia should be monitored more closely in the early stages of COVID-19, for early diagnosis of severity of illness. An understanding of how the severity of COVID-19 infection and LOS are associated has profound implications for the clinical management and mitigation strategies for the disease.

Neurological sequelae of COVID-19: a review.

Abstract: The COVID-19 pandemic has produced a myriad of challenges, including identifying and treating neurological sequelae. COVID-19 can cause olfactory and respiratory dysfunction with average recovery within 1 month and a minority of patients experiencing symptoms at 8-month follow-up. Headaches are also very common (up to 93%) amongst patients with persistent COVID-19 symptoms. COVID-19 illness may also affect cognition, although results are mixed. While many studies have focused on acute COVID-19 symptoms, more longitudinal studies will need to assess the neurological sequelae of the disease. Furthermore, care must be taken when attributing sequelae to COVID-19 illness and not an unrelated cause. Finally, there is concern that COVID-19 may be associated with secondary illnesses, such as Guillain–Barre, and may even contribute to the development of diseases, such as Alzheimer’s.

SARS-CoV-2 Infection and Taste Alteration: An Overview

Abstract: Since the worldwide spread of SARS-CoV-2 infection, the management of COVID-19 has been a challenge for healthcare professionals. Although the respiratory system has primarily been affected with symptoms ranging from mild pneumonia to acute respiratory distress syndrome, other organs or systems have also been targets of the virus. The mouth represents an important route of entry for SARS-CoV-2. Cells in the oral epithelium, taste buds, and minor and major salivary glands express cellular entry factors for the virus, such as ACE2, TMPRSS2 and Furin. This leads to symptoms such as deterioration of taste, salivary dysfunction, mucosal ulcers, before systemic manifestation of the disease. In this review we report and discuss the prevalence and socio-demographics of taste disturbances in COVID-19 patients, analysing the current international data. Importantly, we also take stock of the various hypothesized pathogenetic mechanisms and their impact on the reported symptoms. The literature indicated that COVID-19 patients frequently present with gustatory dysfunction, whose prevalence varies by country, age and sex. Furthermore, this dysfunction also has a variable duration in relation to the severity of the disease. The pathogenetic action is intricately linked to viral action which can be expressed in several ways. However, in many cases these are only hypotheses that need further confirmation.