Twenty-seven studies (23 prospective and four retrospective) were included in the review. Studies reported data for a total of 11,658 polyps (range 43 to 3,438); the number of participants was not reported. QUADAS scores ranged from 8 to 13, with most studies scoring 10 or more.
Twenty-two studies assessed the diagnostic performance of chromoendoscopy. The pooled estimate of sensitivity, derived from a bivariate model, was 95% (95% CI 93 to 97), Ι²=89.8% and the corresponding pooled estimate of specificity was 85% (95% CI 79 to 90), Ι²=79.9%.
Ten studies assessed the diagnostic performance of narrow band imaging. The pooled estimate of sensitivity, derived from a random-effects model, was 94% (95% CI 91 to 97) Ι²=94.5% and the corresponding pooled estimate of specificity was 88% (95% CI 83 to 89), Ι²=17.3%.
Subgroup analyses produced similar results. Meta-regression indicated no statistical difference between chromoendoscopy and narrow band imaging for either sensitivity or specificity and none of the variables assessed was significantly associated with heterogeneity. There was no evidence of publication bias. Summary estimates of positive and negative likelihood ratios were also reported.