BACKGROUND: The coronavirus (COVID-19) pandemic was reported from Wuhan, China, on December 31 , 2019, and the pandemic was spread to more than 212 countries in the globe . This meta-analysis aimed to assess the pooled incidence of COVID-19 complications and to identify the association between the incidence of complications and age .

METHODS: Comprehensive databases, PubMed, Hinari, and Google Scholar, were used to locate potential articles for this review . Data were extracted using Microsoft Excel and imported to the STATA/MP version 16.0 software for analysis . Heterogeneity between studies was assessed using the Cochrane Q test statistics and I 2 test, and small study effect was checked using Egger's statistical test at 5% significant level . Sensitivity analysis was checked . A random-effects model was conducted to estimate the pooled incidence of COVID-19 complications . Univariate meta-regression was conducted to identify the association between the mean ages with each complication .

RESULTS: From the total of 1237 studies , 12 studies were included with a total of 3064 COVID-19 patients . The most complications were acute respiratory distress syndrome (30.93% , 95% CI 21.3-40.6 %) followed by acute liver injury (22.8% , 95% CI 14-31.5 %), shock (10.9% , 95% CI 7.4-14.4 %), acute kidney injury (7% , 95% CI 3.8-10.4 %), and acute cardiac injury (6.4% , 95% CI 2.8-15.6 %). Univariate meta-regression revealed that as the mean age increased by 1 year, the incidence of acute respiratory distress syndrome, acute kidney injury, acute cardiac injury, and shock increased by a factor of 2.9 (β = 2.9 , 95% CI 2.4-3.4, adjusted R 2 = 88), 0.4 (β = 0.4 , 95% CI 0.04-0.72, adjusted R 2 = 54), 1.6 (β = 1.6 , 95% CI 1.1-2.1, adjusted R 2 = 85), and 1.1 (β = 1.1 , 95% CI 0.8-1.5, adjusted R 2 = 26) times respectively .

CONCLUSION: Significant complications of COVID-19 viral infections were reported . Older populations were a high-risk group of developing adverse complications as compared to their counterparts . Health care professionals should give primary attention to those risk group individuals.