Comparative Effectiveness of Cardiac Resynchronization Therapy Defibrillators Versus Standard Implantable Defibrillators in Medicare Patients.
Previous analyses have shown that there is lower mortality with cardiac resynchronization therapy defibrillators (CRT-D) in patients with left bundle branch block (LBBB) but demonstrated mixed results in patients without LBBB. We evaluated the comparative effectiveness of CRT-D versus standard implantable defibrillators (ICDs) separately in patients with LBBB and right bundle branch block (RBBB) using Medicare claims data. Medicare records from CRT-D and ICD recipients from 2002 to 2009 that were followed up for up to 48 months were analyzed. We used propensity scores to match patients with ICD to those with CRT-D. In LBBB, 1:1 matching with replacement resulted in 54,218 patients with CRT-D and 20,763 with ICD, and in RBBB, 1:1 matching resulted in 7,298 patients with CRT-D and 7,298 with ICD. In LBBB, CRT-D had a 12% lower risk of heart failure hospitalization or death (hazard ratio [HR] 0.88, 95% confidence interval 0.86 to 0.90) and 5% lower death risk (HR 0.95, 0.92 to 0.97) compared with ICD. In RBBB, CRT-D had a 15% higher risk of heart failure hospitalization or death (HR 1.15, 1.10 to 1.20) and 13% higher death risk (HR 1.13, 1.07 to 1.18). Sensitivity analysis revealed that accounting for covariates not captured in the Medicare database may lead to increased benefit with CRT-D in LBBB and no difference in RBBB. In conclusion, in a large Medicare population, CRT-D was associated with lower mortality in LBBB but higher mortality in RBBB. The absence of certain covariates, in particular those that determine treatment selection, may affect the results of comparative effectiveness studies using claims data.
Center for Devices and Radiological Health, US Food and Drug Administration, Silver Spring, Maryland.
Robbert
R
Zusterzeel
Center for Devices and Radiological Health, US Food and Drug Administration, Silver Spring, Maryland.
Daniel A
DA
Caños
Center for Devices and Radiological Health, US Food and Drug Administration, Silver Spring, Maryland.
William E
WE
Sanders
Acumen, LLC, SafeRx, Burlingame, California.
Henry
H
Silverman
Acumen, LLC, SafeRx, Burlingame, California.
Thomas E
TE
MaCurdy
Centers for Medicare and Medicaid Services, Baltimore, Maryland.
Christopher M
CM
Worrall
Centers for Medicare and Medicaid Services, Baltimore, Maryland.
Jeffrey
J
Kelman
Center for Devices and Radiological Health, US Food and Drug Administration, Silver Spring, Maryland.
Danica
D
Marinac-Dabic
Center for Devices and Radiological Health, US Food and Drug Administration, Silver Spring, Maryland. Electronic address: david.strauss@fda.hhs.gov.
David G
DG
Strauss
D000368:Aged; D000369:Aged, 80 and over; D002037:Bundle-Branch Block / Q000401:mortality / Q000628:therapy*; D058406:Cardiac Resynchronization Therapy / Q000379:methods; D015331:Cohort Studies; D057186:Comparative Effectiveness Research / Q000379:methods; D017147:Defibrillators, Implantable / Q000009:adverse effects; D005260:Female; D005500:Follow-Up Studies; D006333:Heart Failure / Q000209:etiology / Q000401:mortality; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D006278:Medicare; D008875:Middle Aged; D016896:Treatment Outcome; D014481:United States