Sensitivity analysis. The HTA reports have been removed from the sample to check robustness of results. The numbered items (#) correspond to the PRISMA item numbers (see table 1). In item #5, the relative risk was undefined, but, Fisher's exact test demonstrated no significant difference, (p = 1.00), between the two periods. Overall there was no change in the significance of results in any of the 27 PRISMA items. RR (95% CI) denotes the relative risk with the associated 95% confidence interval.