Fig. 4: Differences in methodological quality scores in COVID-19 compared to historical control articles.

A Time to acceptance was reduced in COVID-19 articles compared to control articles (13.0 [IQR, 5.0–25.0] days vs. 110.0 [IQR, 71.0–156.0] days, n = 347 for COVID-19 and n = 414 for controls; p < 0.0001). B When compared to historical control articles, COVID-19 articles were associated with lower case series score (n = 277 for COVID-19 and n = 277 for controls; p < 0.0001). C COVID-19 articles were associated with lower NOS cohort score compared to historical control articles (n = 174 for COVID-19 and n = 174 for controls; p < 0.0001). D COVID-19 articles were associated with lower NOS case–control score compared to historical control articles (n = 32 for COVID-19 and n = 32 for controls; p = 0.003). E COVID-19 articles were associated with higher diagnostic risk of bias (QUADAS-2) compared to historical control articles (n = 53 for COVID-19 and n = 53 for controls; p = 0.02). For panel A, boxplot captures 5, 25, 50, 75 and 95% from the first to last whisker. Orange represents COVID-19 articles and blue represents control articles. Two-sided Mann–Whitney U-test was conducted to evaluate differences in time to acceptance between COVID-19 and control articles. Differences in study quality scores were evaluated by two-sided Kruskal–Wallis test. Differences in diagnostic risk of bias were quantified by Chi-squares test. p < 0.05 was considered statistically significant.