Objective: To determine the pooled global prevalence of olfactory and gustatory dysfunction in patients with the 2019 novel coronavirus (COVID‐19).Data Sources: Literature searches of PubMed, Embase, and Scopus were conducted on April 19, 2020, to include articles written in English that reported the prevalence of olfactory or gustatory dysfunction in COVID‐19 patients.Review Methods: Search strategies developed for each database contained keywords such as anosmia, dysgeusia, and COVID‐19. Resulting articles were imported into a systematic review software and underwent screening. Data from articles that met inclusion criteria were extracted and analyzed. Meta‐analysis using pooled prevalence estimates in a random‐effects model were calculated.Results: Ten studies were analyzed for olfactory dysfunction (n = 1627), demonstrating 52.73% (95% CI, 29.64%‐75.23%) prevalence among patients with COVID‐19. Nine studies were analyzed for gustatory dysfunction (n = 1390), demonstrating 43.93% (95% CI, 20.46%‐68.95%) prevalence. Subgroup analyses were conducted for studies evaluating olfactory dysfunction using nonvalidated and validated instruments and demonstrated 36.64% (95% CI, 18.31%‐57.24%) and 86.60% (95% CI, 72.95%‐95.95%) prevalence, respectively.Conclusions: Olfactory and gustatory dysfunction are common symptoms in patients with COVID‐19 and may represent early symptoms in the clinical course of infection. Increased awareness of this fact may encourage earlier diagnosis and treatment, as well as heighten vigilance for viral transmission. To our knowledge, this is the first meta‐analysis to report on the prevalence of these symptoms in COVID‐19 patients.

The aim of this systematic review and meta-analysis was to investigate the prognostic utility of the platelet-to-lymphocyte ratio (PLR) in head and neck cancer. Medline (via PubMed), EMBASE, Scopus, and the Cochrane Library databases were searched from their inception to May 2017 for relevant literature. A systematic review and meta-analysis were performed to generate the pooled hazard ratios (HR) for overall survival (OS) and disease-specific survival (DSS). The study was conducted in accordance with the Cochrane Handbook and PRISMA guidelines. Risk of bias was assessed using the QUIPS tool. The logarithm of the HR with standard error was used as the primary summary statistic. Heterogeneity was assessed using Cochran’s Q and Higgins’ I². A total of 13 studies were included in the final analysis, combining data from 4,541 patients. The results demonstrated that an elevated PLR was significantly associated with poorer OS [HR 1.85, 95% CI 1.35–2.52, p < 0.00001] and DSS [HR 1.57, 95% CI 1.25–1.97, p < 0.0001]. Significant heterogeneity was detected for the pooled end points. Subgroup analysis demonstrated reduction of heterogeneity by controlling for sample size and cutoff value. 95% prediction intervals showed wide ranges crossing the null threshold.