Proclemer A, Arenal A, Lunati M, Ferrer JBM, Hersi A, Manotta L, Gasparini M. Association of Long vs Standard Detection Intervals for Implantable Cardioverter-Defibrillators With Hospitalizations and Costs. JAMA. 2014;312(5):555–557. doi:10.1001/jama.2014.4783
The role of implantable cardioverter-defibrillators (ICDs) in reducing sudden and overall mortality is established.1 Recently, an ICD programming strategy that allows delayed detection of arrhythmias was shown to reduce unnecessary and inappropriate therapies.2,3
In this exploratory analysis of the Avoid Delivering Therapies for Non-sustained Arrhythmias in ICD Patients III (ADVANCE III) trial, we assessed the association of programming a long-detection interval on hospitalizations, length of stay (LOS) in the hospital, and costs.
The ADVANCE III study design has been published.4 Briefly, at 94 international centers between 2008 and 2010, 1902 patients receiving their first ICD were randomized to a long-detection interval group (the number of intervals to detect arrhythmias was programmed at 30 of 40) or a standard interval group (18 of 24 intervals). Patients were blinded to assignment. In both groups, antitachycardia pacing during capacitor charge was activated. Patients were followed up every 3 months for 1 year.
Each institutional review board approved the study and written informed consent was obtained from each participant. Diagnosis, delivered therapies, recovery, and discharges dates for hospitalizations related to each adverse event were requested in the case report forms. An independent committee reviewed all events, querying the center in case of unclear information.
The economic effect was a prespecified secondary outcome. Overall and cardiovascular hospitalization rates, time to first hospitalization, and LOS in the hospital were exploratory outcomes. To account for different follow-up durations, the number of hospitalizations and LOS were adjusted by considering the total number of patient-years and estimating annual incidence rates. Time to first event curves were generated using the Kaplan-Meier method and survival distributions were compared by the log-rank test.
The International Classification of Diseases, Ninth Revision, Clinical Modification, codes were used to assign the proper diagnosis related group (and cost) for each hospitalization. Cost per patient-year was presented as mean and 95% confidence interval and was adjusted for the total number of patient-years. A mean cost ratio was performed to compare costs between groups. Stata version 12.0 (StataCorp) was used, and a 2-sided probability value of ≤.05 was used for declaring statistical significance.
Of 1902 patients randomized, the 948 in the long-detection interval and 954 in the standard interval groups presented similar demographics as previously described.2 During 12 months of follow-up, 546 patients reported 865 overall hospitalizations (473 hospitalizations in 302 patients in the standard interval group and 392 hospitalizations in 244 patients in the long-detection interval group) (Table).
The long-detection interval group was associated with a longer time to the first overall hospitalization (hazard ratio, 0.81 [95% CI, 0.68-0.95]; P = .01) and cardiovascular hospitalization (hazard ratio, 0.81 [95% CI, 0.67-0.98]; P = .03) compared with the standard interval group (Figure), and reductions in overall hospitalization rate (52.3 [95% CI, 47.7-57.3] vs 43.8 [95% CI, 39.6-48.4], respectively, per 100 patient-years; incidence rate ratio, 0.84 [95% CI, 0.73-0.96]; P = .005) and LOS (470 [95% CI, 456-484] vs 407 [95% CI, 394-421] per 100 patient-years; incidence rate ratio, 0.87 [95% CI, 0.83-0.91]; P < .001), without difference in mortality.2
Similar results were found for cardiovascular hospitalization rates and LOS (Table). The long-detection interval group was also associated with a mean reduction of $299 per patient-year for overall hospitalizations and $329 per patient-year for cardiovascular hospitalizations compared with the standard interval group (Table).
These exploratory analyses of the ADVANCE III trial found that a programming strategy combining a long-detection interval and antitachycardia pacing during charging was associated with an increase in the time to first hospitalization and reductions in hospitalization rate, LOS, and the cost per patient-year compared with standard interval programming.
The reduction in all-cause hospitalizations was mainly driven by the reduction in cardiovascular hospitalizations (P = .004). This result is consistent with the RELEVANT trial,5 which in contrast enrolled only patients with nonischemic cardiomyopathy treated with cardiac resynchronization therapy defibrillators.
As a limitation, costs were estimated, not directly collected, and follow-up was limited to 1 year. These favorable results for resource use complement the demonstrated clinical effectiveness of the long-detection interval strategy and come without additional costs for the hospitals or patients.
Corresponding Author: Maurizio Gasparini, MD, Chief of Electrophysiology and Pacing Unit, Humanitas Research Hospital, IRRCCS, Via Manzoni 56, 20089 Rozzano, Italy (email@example.com).
Author Contributions: Dr Gasparini had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.
Study concept and design: Proclemer, Lunati, Manotta, Gasparini.
Acquisition, analysis, or interpretation of data: Proclemer, Arenal, Ferrer, Hersi, Gasparini.
Drafting of the manuscript: Proclemer, Hersi, Gasparini.
Critical revision of the manuscript for important intellectual content: Proclemer, Arenal, Lunati, Ferrer, Hersi, Manotta.
Statistical analysis: Arenal.
Administrative, technical, or material support: Manotta.
Study supervision: Lunati, Ferrer, Hersi, Gasparini.
Conflict of Interest Disclosures: The authors have completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Dr Arenal reported serving as consultant and speaker for Medtronic, Boston Scientific, and St Jude. Dr Lunati reported serving as consultant and speaker for educational presentations for Medtronic, Boston Scientific, St Jude, and Sorin. Dr Gasparini reported serving on advisory boards for Medtronic and Boston Scientific. No other disclosures were reported.
Funding/Support: The ADVANCE III Study was supported by Medtronic Inc.
Role of the Sponsor: Medtronic had a role in the design and conduct of the study; had no role in the collection of data; had a role in the management; had no role in the analysis and interpretation of the data; had a role in the preparation, review, or approval of the manuscript; and had no role in the decision to submit the manuscript for publication.
Additional Contributions: We thank Axel Kloppe, MD (Medizinische Klinik II, Kardiologie und Angiologie, Berufsgenossenschaftliches Universitätsklinikum Bergmannsheil, Ruhr-Universität-Bochum, Bochum, Germany), Marcin Gulaj, MD (MSWiA Hospital, Bialystok, Poland), and Maurits C. E. F. Wijfels, PhD (St Antonius Ziekenhuis Hospital, Nieuwegein, the Netherlands), for their contributions in the acquisition and interpretation of the data. We also acknowledge all the contributions made by the investigators of the enrolling centers of the ADVANCE III Trial in the acquisition of the data. None of the individuals acknowledged were compensated for their contributions.