ObjectiveTo 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.DesignSystematic review and meta-analysis.Data sourcesPubMed, Embase, Scopus, Cochrane Library, and medRxiv from inception to 3 October 2021.Review methodsTwo 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 synthesisTwo 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 measuresThe 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.Results18 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.ConclusionsA 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 registrationPROSPERO CRD42021283922.

Trip.com. James Liang is the co-founder, former CEO, and current Chairman of Trip.com. No other co-author has any financial relationship with Trip. Neither the results nor the paper was pre-screened by anyone. The experiment was registered with the American Economics Association after the experiment had begun (when Bloom and Han were invited to analyze the data) but before any data was analyzed. The experiment was IRB-exempt as the experiment was initiated by Trip.com before Bloom and Han joined the project, and only anonymous data was shared with the Stanford team. The views expressed herein are those of the authors and do not necessarily reflect the views of the National Bureau of Economic Research.NBER working papers are circulated for discussion and comment purposes. They have not been peer-reviewed or been subject to the review by the NBER Board of Directors that accompanies official NBER publications.

Coronavirus disease 2019 (COVID-19) is an emerging infectious disease first identified in Wuhan City, Hubei Province, China. As of 19 February 2020, there had been 333 confirmed cases reported in Shanghai, China. This study elaborates on the epidemiological and clinical characteristics of COVID-19 based on a descriptive study of the 333 patients infected with COVID-19 in Shanghai for the purpose of probing into this new disease and providing reference. Among the 333 confirmed cases in Shanghai, 172 (51.7%) were males and 161 (48.3%) were females, with a median age of 50 years. 299 (89.8%) cases presented mild symptoms. 139 (41.7%) and 111 (33.3%) cases were infected in Wuhan and Shanghai, respectively. 148 (44.4%) cases once had contact with confirmed cases before onset, while 103 (30.9%) cases had never contacted confirmed cases but they had a sojourn history in Wuhan. The onset date of the first case in Shanghai was 28 December, with the peak appearing on 27 January. The median incubation period of COVID-19 was estimated to be 7.2 days. 207 (62.2%) cases had fever symptoms at the onset, whereas 273 (82.0%) cases experienced fever before hospitalization. 56 (18.6%) adults experienced a decrease in white blood cell and 84 (42.9%) had increased C-reactive protein after onset. Elderly, male and heart disease history were risk factors for severe or critical pneumonia. These findings suggest that most cases experienced fever symptoms and had mild pneumonia. Strengthening the health management of elderly men, especially those with underlying diseases, may help reduce the incidence of severe and critical pneumonia. Time intervals from onset to visit, hospitalization and diagnosis confirmed were all shortened after Shanghai's first-level public health emergency response. Shanghai's experience proves that COVID-19 can be controlled well in megacities.

Aims:To compare the efficacy and safety of dipeptidyl peptidase-4 inhibitors (DPP-4is) and sodium-glucose cotransporter-2 inhibitors (SGLT-2is) as monotherapy or add-on to metformin (Met) in patients with type 2 diabetes mellitus (T2DM). Materials and Methods:PubMed, Embase and ClinicalTrials.gov sites were systematically searched for randomized controlled trials to assess the efficacy and safety of DPP-4is and SGLT-2is in patients with T2DM. Risk ratio (RR) and weighted mean difference (WMD) were used to evaluate outcomes.Results: In the analysis of 25 randomized trials, which involved 14 619 patients, SGLT-2is were associated with a significantly stronger reduction in haemoglobin A1c (HbA1c) (WMD 0.13%, 95% credible interval [CI], 0.04%-0.22%, P = .005) and fasting plasma glucose (FPG) (WMD 0.80 mmol/L, 95% CI, 0.58-1.01 mmol/L, P < .00001) than were DPP-4is. However, no significant difference between the 2 drug categories was found in the risk of hypoglycaemic events (RR, 0.99; 95% CI, 0.78-1.26, P = .92). SGLT-2is plus Met was associated with a more significant decrease in FPG (WMD 0.71 mmol/L, 95% CI, 0.43-1.00 mmol/L, P < .00001) than was DPP-4is plus Met. However, no differences were found in the reduction of HbA1c (WMD 0.11%, 95% CI, −0.03%-0.25%, P = .12) or the risk of hypoglycaemic events (RR, 1.02; 95% CI, 0.80-1.31, P = .86).Conclusions: This review revealed that, compared to DPP-4is, SGLT-2is significantly reduced HbA1c, FPG and body weight without increasing the risk of hypoglycaemia in diabetes treatment. | MATERIALS AND METHODS | Data sources and search strategyElectronic searches were performed in PubMed, Embase and ClinicalTrials.gov sites from inception to May 1, 2017 using the following search terms: linagliptin, saxagliptin, sitagliptin, dipeptidyl peptidase-4 inhibitors, DPP-4is, canagliflozin, dapagliflozin, empagliflozin, ipragliflozin, ertugliflozin, sodium-glucose cotransporter-2 inhibitors, SGLT-2is. There was no restriction on language of publication.The reference lists of the related studies were manually examined to identify any additional publications relevant to our analysis. | Inclusion and exclusion criteriaInclusion criteria were as follows: (1 Exclusion criteria were as follows: (1) trials involving animals or healthy human subjects; (2) non-randomized trials; (3) letters or case reports; (4) articles that provided inadequate information of interest or primary data; (5) trials with a duration of less than 12 weeks. | Study selection and data extractionTwo independent researchers (Z. W. and J. S.) screened the search results and selected studies in strict accordance with the inclusion and exclusion criteria. Any resulting discrepancies were resolved by discussion with a third researcher (X. D.).The following data were independently extracted from the studies using a standardized form that included: trial characteristics (first author, publication year, sample size, duration of therapy, medications, the National Clinical Trial number); participants' baseline (age, gender, HbA...

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