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Long Covid: A Systematic Review and Meta-Analysis of 120,970 Patients

Background: The long-term consequences of the coronavirus disease 19 (COVID-19) are likely to be frequent but results hitherto are inconclusive. Therefore, we aimed to summarize the state-of-the-art literature in relation to long COVID symptomatology, using a systematic review and meta-analysis of observational studies. Methods: A systematic search in several databases was carried out up to 12 January 2022 for observational studies reporting the incidence rate of long COVID signs and symptoms divided according to body systems affected and defined using the World Health Organization criteria. Data are reported as incidence and 95% confidence intervals (CIs). Several sensitivity and meta-regression analyses were moreover performed. Findings: Among 11,162 papers initially screened, 196 studies were included, consisting of 120,970 participants (mean age: 52.3 years;48.8% females) who were followed-up for a median of six months. The incidence of any long COVID symptomatology was 56.9% (95%CI: 52.2-61.6). General long COVID signs and symptoms were the most frequent (incidence of 31%), digestive issues the less frequent (7.7%). Higher percentage of females moderated the onset of any, neurological, general and cardiovascular long COVID symptomatology, whilst higher mean age was associated with higher incidence of psychiatric, respiratory, general, digestive and skin conditions. The incidence of long COVID symptomatology was different according to continent, age and follow-up length. Interpretation: Long COVID is a common condition in patients who have been infected with SARS-CoV-2, whether symptomatically or asymptomatically, and often regardless of the severity of the acute illness indicating the need for more cohort studies on this topic.