In Reply In response to the letter by Min and Newby that decries the reported inaccuracies and errors in my Viewpoint,1 a few clarifications are in order. First, the assertion that the Scottish Computed Tomography of the Heart (SCOT-HEART) trial2 reflects the preponderance of cardiac care globally is not supported by current clinical practice, which skews toward functional stress testing as a first-line strategy rather than the sequential combination of functional stress testing and coronary computed tomography angiography. Second, the number needed to treat of 250 refers to the pooled estimate of 0.4% absolute risk difference based on the meta-analysis by Foy et al as I discussed,1 which included the interim results from the SCOT-HEART trial. Third, the difference in commencement of preventive therapies is reported to be modest—402 (19.4%) vs 305 (14.7%).2 For example, a 10% greater increase from baseline in antiplatelet therapy and an 8% greater increase in statin therapy is unlikely to account for the large treatment effect, given the 30% risk reduction associated with these therapies relative to placebo in patients with stable coronary artery disease.3,4 Fourth, I agree that the observed relative risk reduction point estimate of 41% (95% CI, 16-59) has substantially overlapping confidence interval with the expected estimate of 19% (95% CI, 5-31). Thus, the observed data are consistent with as little as a 16% relative risk reduction, which translates to an absolute risk reduction of 0.5%, or a number needed to treat of 200, a number which is more plausible and consistent with the postulated mechanisms of benefit.
Kaul S. Coronary Computed Tomography Angiography as the Investigation of Choice for Stable Chest Pain—Reply. JAMA Cardiol. 2019;4(9):948–949. doi:10.1001/jamacardio.2019.2087
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