Fig. 4
Forest plot of paired sensitivities and specificities of study algorithms ascertaining prevalent heart failure. Legend: Algorithms sorted by diagnostic code position. Summary points are estimated using a bivariate random effects model. CI indicates confidence intervals; FN, false negatives; FP, false positives; I2, I2 statistic describing the percentage of variation across studies that is due to heterogeneity rather than chance; TN, true negatives and TP, true positive