Fig. 4

The result is the pooled estimate of the 9 included studies by random effect model. RR: rate ratios. There was a statistically significant association (pooled RR = 1.54, 95% CI: 1.25–1.89, p < 0.0001; I2 = 45%, p = 0.07, Power = 1.0) between obesity and risk of difficult laryngoscopy