Response to letter to the editor concerning the article “The clinical and economic impact of extended battery longevity of a substernal extravascular implantable cardioverter defibrillator”
Bibliographic record
Abstract
We have read the comments made by Mealing and colleagues and appreciate the opportunity to further clarify certain aspects of our work. Thank you for your interest in our manuscript. The model employed a 3-month cycle time, selected because of the life-long time horizon. No patient in the model was “immune” to complications as the full cohort of patients having a replacement faced the probability of complication at the transition between the “generator replacement” and “replacement complication” states. This was intended to represent an average timing of peri-procedural complications which could occur either during the procedure or for 6–12 months afterward. The complications have proper impact on the overall mortality and cost calculations, and any error related to timing would be limited to a one-cycle difference in the discounted results which is minimal. The perspectives for each country were chosen to represent the stakeholder most likely to impact the decision of ICD type given an indication for therapy. In the United States, a fractionated payer system pays for a generic procedure and does not differentiate between models, so the choice is made at the hospital. The rest of the countries have more unified payers with some even employing model-specific reimbursement payment amounts. Device longevity was not fixed in the model, there was a time-varying probability of device replacement. It was based on clinical observation from patients in the Pivotal study (NCT04060680) combined with engineering model projections as displayed in Figure 2. We did acknowledge uncertainty about this in the limitations (“Modeled longevity…could be impacted by changes in technology”) and incorporated a robust sensitivity analysis varying the expected longevity by two standard deviations based on current data. We acknowledge that the substernal defibrillator is new technology, but there is robust post-market clinical study activity that will enhance the evidence base (NCT06048731). We accounted for concerns about uncertainty in cost parameters a similar way and found in the sensitivity analysis that cost had an even smaller impact on model outcomes. The substernal ICD carries a strong mechanism for comparative energy efficiency. With a projected 60% improvement in device longevity, one would expect the avoided replacement surgeries and cost savings predicted by this model.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.005 | 0.045 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.002 | 0.002 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.002 | 0.002 |
| Scholarly communication | 0.004 | 0.003 |
| Open science | 0.003 | 0.001 |
| Research integrity | 0.027 | 0.030 |
| Insufficient payload (model declined to judge) | 0.013 | 0.010 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".