Annals of internal medicine ORIGINAL RESEARCH Comparative Effectiveness of Multivessel Coronary bypass Surgery and Multivessel Percutaneous Coronary Intervention A Cohort Study Mark A Hlatky, MD; Derek B. Boothroyd, PhD; Laurence Baker, PhD; Dhruv S Kazi, MD, MS: Matthew D. Solomon, MD, PhD Tara L. Chang, MD, MS: David Shilane, PhD; and Alan S Go, MD Background: Randomized trials of coronary artery bypass graft lower mortality was significantly greater(interaction P <0.002 for (CABG)surgery and percutaneous coronary intervention(PCI) sug- each)among patients with diabetes(HR, 0. 88), a history of tobacco gest that patient characteristics modify the effect of treatment use(HR, 0.82), heart failure(HR, 0.84), and peripheral arterial disease(HR, 0.85). The overall predicted difference in survival be- tween CABG and PCI treatment over 5 years was 0.053 life-year Objective: To assess whether clinical characteristics modify the comparative effectiveness of CABG versus PCI in an unselected, (range, -0.017 to 0.579 life-years). Patients with diabetes, heart failure, peripheral arterial disease, or tobacco use had the largest predicted differences in survival after CABG, whereas those with none of these factors had slightly better survival after PCI Limitation: Treatments were chosen by patients and physicians Setting: United States, 1992 to 2008 rather than being randomly assigned Patients: Medicare beneficiaries aged 66 years or older Conclusion: Multivessel CABG is associated with lower long-term mortality than multivessel PCI in the community setting. This asso- Intervention: Multivessel CABG or multivessel PCI ciation is substantially modified by patient characteristics, with im- provement in survival concentrated among patients with diabetes, Measurements: The CABG-PCl hazard ratio(HR) for all-cause tobacco use, heart failure, or peripheral arterial disease mortality, with prespecified treatment-by-covariate interaction tests and the absolute difference in life-years of survival in dinical sub- Primary Funding Source: National Heart, Lung, and Blood groups after CABG or PCI, both over 5 years of follow-up Institute Results: Among 105 156 propensity score-matched patients Ann Intem Med.2013;158:727-734. www.annals.org CABG was associated with lower mortality than PCI(HR, 0.92 For author affiliations, see end of text. 5%cl,0.90to0.951:P<0.001).AssociationofCabgwithThisartidewaspublishedatwww.annals.orgon23April2013. oronary artery bypass graft( CABG)surgery and per- treatments overall and in targeted subgroups by using read cutaneous coronary intervention(PCI) are among the ily available data from nationally representative patients most common major procedures performed worldwide. treated in real-world practices Either can be used to treat multivessel coronary artery dis- The purpose of this study was to compare the mortal- ease, and their comparative effectiveness has been assessed ity rates of Medicare beneficiaries who had multivessel in several randomized trials(1-7). A recent collaborative CABG or multivessel PCi and to assess whether the com- analysis of 10 trials comparing CABG with PCI showed parative effectiveness of these procedures was modified by that overall mortality risk was slightly, but not signifi- patient characteristics cantly, reduced by CABG and that the effect of CABG treatment on mortality was significantly modifed by dia METHODS betes mellitus and age(8) Randomized trials are accepted as the reference stan- The study population comprised fee-for-service Medi dard for comparing treatments but are diffcult to perform care beneficiaries who had multivessel CABg or multives and usually enroll patients selectively. For example, only sel PCI between 1992 and 2008. To permit a 1-year look about 10 000 patients have been randomly assigned to conditions, we restricted the study population to individ- CABG or PCI, a tiny fraction of the millions of patients uals aged 66 years or older who had Part A and Part B worldwide who have had one of these procedures. Al- though the high-quality data from randomized trials can be dicare coverage and were not enrolled in a medicare leveraged into treatment recommendations, it has been in- HMO. The index coronary revascularization procedures creasingly recognized that patients enrolled in clinical trials are generally younger and healthier than those seen in everyday practice. Furthermore, these trials are generally ee a/so underpowered to examine variation in the treatment effect Print according to clinical characteristics of the patient. analysis Summary for Patients 1-24 of Medicare claims provides the opportunity to compare O 2013 American College of Physicians727Comparative Effectiveness of Multivessel Coronary Bypass Surgery and Multivessel Percutaneous Coronary Intervention A Cohort Study Mark A. Hlatky, MD; Derek B. Boothroyd, PhD; Laurence Baker, PhD; Dhruv S. Kazi, MD, MS; Matthew D. Solomon, MD, PhD; Tara I. Chang, MD, MS; David Shilane, PhD; and Alan S. Go, MD Background: Randomized trials of coronary artery bypass graft (CABG) surgery and percutaneous coronary intervention (PCI) sug￾gest that patient characteristics modify the effect of treatment on mortality. Objective: To assess whether clinical characteristics modify the comparative effectiveness of CABG versus PCI in an unselected, general patient population. Design: Observational treatment comparison using propensity score matching and Cox proportional hazards models. Setting: United States, 1992 to 2008. Patients: Medicare beneficiaries aged 66 years or older. Intervention: Multivessel CABG or multivessel PCI. Measurements: The CABG–PCI hazard ratio (HR) for all-cause mortality, with prespecified treatment-by-covariate interaction tests, and the absolute difference in life-years of survival in clinical sub￾groups after CABG or PCI, both over 5 years of follow-up. Results: Among 105 156 propensity score–matched patients, CABG was associated with lower mortality than PCI (HR, 0.92 [95% CI, 0.90 to 0.95]; P
0.001). Association of CABG with lower mortality was significantly greater (interaction P
0.002 for each) among patients with diabetes (HR, 0.88), a history of tobacco use (HR, 0.82), heart failure (HR, 0.84), and peripheral arterial disease (HR, 0.85). The overall predicted difference in survival be￾tween CABG and PCI treatment over 5 years was 0.053 life-years (range, 0.017 to 0.579 life-years). Patients with diabetes, heart failure, peripheral arterial disease, or tobacco use had the largest predicted differences in survival after CABG, whereas those with none of these factors had slightly better survival after PCI. Limitation: Treatments were chosen by patients and physicians rather than being randomly assigned. Conclusion: Multivessel CABG is associated with lower long-term mortality than multivessel PCI in the community setting. This asso￾ciation is substantially modified by patient characteristics, with im￾provement in survival concentrated among patients with diabetes, tobacco use, heart failure, or peripheral arterial disease. Primary Funding Source: National Heart, Lung, and Blood Institute. Ann Intern Med. 2013;158:727-734. www.annals.org For author affiliations, see end of text. This article was published at www.annals.org on 23 April 2013. Coronary artery bypass graft (CABG) surgery and per￾cutaneous coronary intervention (PCI) are among the most common major procedures performed worldwide. Either can be used to treat multivessel coronary artery dis￾ease, and their comparative effectiveness has been assessed in several randomized trials (1–7). A recent collaborative analysis of 10 trials comparing CABG with PCI showed that overall mortality risk was slightly, but not signifi- cantly, reduced by CABG and that the effect of CABG treatment on mortality was significantly modified by dia￾betes mellitus and age (8). Randomized trials are accepted as the reference stan￾dard for comparing treatments but are difficult to perform and usually enroll patients selectively. For example, only about 10 000 patients have been randomly assigned to CABG or PCI, a tiny fraction of the millions of patients worldwide who have had one of these procedures. Al￾though the high-quality data from randomized trials can be leveraged into treatment recommendations, it has been in￾creasingly recognized that patients enrolled in clinical trials are generally younger and healthier than those seen in everyday practice. Furthermore, these trials are generally underpowered to examine variation in the treatment effect according to clinical characteristics of the patient. Analysis of Medicare claims provides the opportunity to compare treatments overall and in targeted subgroups by using read￾ily available data from nationally representative patients treated in real-world practices. The purpose of this study was to compare the mortal￾ity rates of Medicare beneficiaries who had multivessel CABG or multivessel PCI and to assess whether the com￾parative effectiveness of these procedures was modified by patient characteristics. METHODS The study population comprised fee-for-service Medi￾care beneficiaries who had multivessel CABG or multives￾sel PCI between 1992 and 2008. To permit a 1-year look￾back period and document the presence of comorbid conditions, we restricted the study population to individ￾uals aged 66 years or older who had Part A and Part B Medicare coverage and were not enrolled in a Medicare HMO. The index coronary revascularization procedures See also: Print Summary for Patients....................... I-24 Annals of Internal Medicine Original Research © 2013 American College of Physicians 727