Neurological Symptoms, Comorbidities, and Complications of COVID-19: A Literature Review and Meta-Analysis of Observational Studies

Abstract

<b><i>Background:</i></b> Recently, it has been shown that coronavirus disease 2019 (COVID-19), which has caused a pandemic since December 2019, can be accompanied by some neurological disorders. This study aimed to assess the prevalence of the most common neurological symptoms and comorbidities and systematically review the literature regarding the most prevalent neurological complications of COVID-19 infection. <b><i>Methods:</i></b> All relevant studies had been collected from PubMed, Scopus, Embase, and Web of Science databases. All extracted data were analyzed using Stata version 11.2. The <i>I</i>² index was applied, and a random-effects model or a fixed-effects model was used for pooled estimation to assess the heterogeneity of studies. Furthermore, Egger and Beeg’s tests were used to evaluate the publication bias. <b><i>Results:</i></b> Fifty-seven studies (26 observational and 31 case reports) were included (including 6,597 COVID-19 patients). The most prevalent general symptoms were fever, cough, and dyspnea with 84.6% (95% CI: 75.3–92.1; <i>I</i>² = 98.7%), 61.3% (95% CI: 55.3–67.0; <i>I</i>² = 94.6%), and 34.2% (95% CI: 25.6–43.4; <i>I</i>² = 97.7%), respectively. Neurological symptoms observed among COVID-19 patients were fatigue, gustatory dysfunction, anorexia, olfactory dysfunction, headache, dizziness, and nausea with 42.9% (95% CI: 36.7–49.3; <i>I</i>² = 92.8%), 35.4% (95% CI: 11.2–64.4; <i>I</i>² = 99.2%), 28.9% (95% CI: 19.9–38.8; <i>I</i>² = 96.3%), 25.3% (95% CI: 1.6–63.4; <i>I</i>² = 99.6%), 10.1% (95% CI: 2.7–21.0; <i>I</i>² = 99.1%), 6.7% (95% CI: 3.7–10.5; <i>I</i>² = 87.5%), and 5.9% (95% CI: 3.1–9.5; <i>I</i>² = 94.5%). The most prevalent neurological comorbidity in COVID-19 was cerebrovascular disease with 4.3% (95% CI: 2.7–6.3; <i>I</i>² = 78.7%). <b><i>Conclusion:</i></b> The most prevalent neurological manifestations of COVID-19 include fatigue, gustatory dysfunction, anorexia, olfactory dysfunction, headache, dizziness, and nausea. Cerebrovascular disorders can either act as a risk factor for poorer prognosis in COVID-19 patients or occur as a critical complication in these patients. Guillain-Barre syndrome, encephalitis, and meningitis have also been reported as complications of COVID-19.