ORIGINAL RESEARCH I Comparative Effectiveness of CABG and PCI Figure 3. Distribution of the estimated life-years of survival added by CABG compared with PCI over 5-y follow-up 10 Favors Pc1 Favors CABG Predicted Difference(CABG-PCD) in 5-y Survival, y population is indicated on the vertical axis, te-years of survival added over 5-y follow-up are shown on th d-whisker plot indicates the 50th percentile as the the box: the 25th and 75th percentiles as the left and right edges and the 5th and 95th percentiles as the left and right respectively. The mean is indicated by the point within the box. tery bypass graft; PCI= percutaneous coronary in areprovidedintheAppendix(availableatwww.annalsmeDicare(10).Thisbodyofevidencesuggeststhattheuse of CABG rather than PCI is likely to reduce mortality for the average patient with multivessel coronary disease DISCUSSION Although the expected fo an average pa Comparative effectiveness research aims to provide in- are clearly important, outcomes for individual patients may formation needed by decision makers, particularly phy differ. In this study, we found that several patient charac- cians and their patients, to choose among alternative teristics significantly modified the comparative effective approaches to clinical management. Therefore, it is impor- less of CABG and PCI such that the expected survival tant to understand not only how treatments affect an v- difference between the procedures varied widely among in- erage patient"but also how their effectiveness may vary dividuals(Figure 3). Patients with a history of peripheral among specific patients with different characteristics. Ran arterial disease, tobacco use, diabetes, or heart failure had a domized clinical trials are well-suited to compare treatment particular survival advantage from CABG(Figures 2 and 4). Conversely, patients with none of these characteristics ity criteria and limited sample sizes, they are less had slightly better survival with PCI. This variation in the suitable for examining variations in clinical effectiveness comparative effectiveness of CABG and PCI underscores across patient populations treated in typical practice the importance of individualizing treatment The comparative effectiveness of treatments is usually In our study, we evaluated the treatment effectiveness measured in relative terms by using HRs, risk ratios, or of coronary revascularization among a large population of odds ratios. These relative measures are well-suited to assess real-world patients and providers. Coronary artery bypass whether the treatment"works" in a consistent manner grafting was associated with significantly lower mortality across studies and patient subgroups. However, even with than PCI in the overall patient population, with an HR of the same relative risk reduction, the absolute risk difference 0.92(CL, 0.90 to 0.95; P< 0.001). This finding is similar from treatment is larger among high-risk patients. In this to the overall HR of 0.91 found in a prior analysis of study, we calculated the expected absolute difference in pooled data from 10 randomized trials( 8)and is consistent survival over 5 years to illustrate the substantial variation with the results of a recent study comparing CABG and among patients in the comparative effectiveness of CABG PCI on the basis of data from clinical registries linked with and PCI(Figure 3). The number of life-years added by 73221 May 2013 Annals of Internal Medicine Volume 158. Number 10 www.annals.orgare provided in the Appendix (available at www.annals .org). DISCUSSION Comparative effectiveness research aims to provide in￾formation needed by decision makers, particularly physi￾cians and their patients, to choose among alternative approaches to clinical management. Therefore, it is impor￾tant to understand not only how treatments affect an “av￾erage patient” but also how their effectiveness may vary among specific patients with different characteristics. Ran￾domized clinical trials are well-suited to compare treatment efficacy for the average patient, but because of their narrow eligibility criteria and limited sample sizes, they are less suitable for examining variations in clinical effectiveness across patient populations treated in typical practice settings. In our study, we evaluated the treatment effectiveness of coronary revascularization among a large population of real-world patients and providers. Coronary artery bypass grafting was associated with significantly lower mortality than PCI in the overall patient population, with an HR of 0.92 (CI, 0.90 to 0.95; P
0.001). This finding is similar to the overall HR of 0.91 found in a prior analysis of pooled data from 10 randomized trials (8) and is consistent with the results of a recent study comparing CABG and PCI on the basis of data from clinical registries linked with Medicare (10). This body of evidence suggests that the use of CABG rather than PCI is likely to reduce mortality for the average patient with multivessel coronary disease. Although the expected outcomes for an average patient are clearly important, outcomes for individual patients may differ. In this study, we found that several patient charac￾teristics significantly modified the comparative effective￾ness of CABG and PCI such that the expected survival difference between the procedures varied widely among in￾dividuals (Figure 3). Patients with a history of peripheral arterial disease, tobacco use, diabetes, or heart failure had a particular survival advantage from CABG (Figures 2 and 4). Conversely, patients with none of these characteristics had slightly better survival with PCI. This variation in the comparative effectiveness of CABG and PCI underscores the importance of individualizing treatment. The comparative effectiveness of treatments is usually measured in relative terms by using HRs, risk ratios, or odds ratios. These relative measures are well-suited to assess whether the treatment “works” in a consistent manner across studies and patient subgroups. However, even with the same relative risk reduction, the absolute risk difference from treatment is larger among high-risk patients. In this study, we calculated the expected absolute difference in survival over 5 years to illustrate the substantial variation among patients in the comparative effectiveness of CABG and PCI (Figure 3). The number of life-years added by Figure 3. Distribution of the estimated life-years of survival added by CABG compared with PCI over 5-y follow-up. Matched Cohort, % Predicted Difference (CABG – PCI) in 5-y Survival, y Favors PCI Favors CABG –0.1 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0 5 10 15 20 25 The percentage of the study population is indicated on the vertical axis, and the life-years of survival added over 5-y follow-up are shown on the horizontal axis. The box-and-whisker plot indicates the 50th percentile as the line within the box; the 25th and 75th percentiles as the left and right edges of the box, respectively; and the 5th and 95th percentiles as the left and right whiskers, respectively. The mean is indicated by the point within the box. CABG coronary artery bypass graft; PCI percutaneous coronary intervention. Original Research Comparative Effectiveness of CABG and PCI 732 21 May 2013 Annals of Internal Medicine Volume 158 • Number 10 www.annals.org