Association Between Use of WATCHMAN Device and 1-Year Mortality Using High-Dimensional Propensity Scores to Reduce Confounding
Bibliographic record
Abstract
BACKGROUND: Previous observational studies showed left atrial appendage occlusions with the WATCHMAN device reduced 1-year mortality, which conflicted with evidence generated from randomized controlled trials. We proposed to use the high-dimensional propensity score (hdPS) to assist in nonactive comparator selection (prevalent user of medication) and compared 1-year mortality between patients with atrial fibrillation who received the WATCHMAN device (percutaneous left atrial appendage occlusion device [pLAAO]) and direct oral anticoagulants in 2 matched cohorts based on (1) traditional propensity score (PS) and (2) integrating traditional PS with information learned from hdPS. METHODS: Patients entered the cohort once diagnosed with atrial fibrillation in the 15% of Medicare fee-for-service claims database from 2011 to 2018. Patients could enter the study cohort upon receiving WATCHMAN or at an outpatient visit with an atrial fibrillation diagnosis, respectively. We used PS matching with a 1:3 ratio for patients in pLAAO and direct oral anticoagulant groups. In cohort 2, we implemented a multistep approach with information learned from hdPS. The Cox proportional hazards model was used to estimate hazard ratios of outcomes with 95% CIs. RESULTS: In cohort 1, we identified 1159 and 3477 patients in the pLAAO and direct oral anticoagulant groups with a mean age of 78.1 versus 77.5 years, 44.9% versus 40.8% of women, and a 1-year mortality rate of 8.02 versus 8.97/100 person-years (hazard ratio, 0.87 [95% CI, 0.69-1.09]). With the support of hdPS, in cohort 2, we excluded patients with malignant cancer and added frailty score in the PS model. We identified 953 and 2859 patients in the pLAAO and direct oral anticoagulant groups with a mean age of 78.1 versus 77.9 years, 47.2% versus 46.1% of women, and a 1-year mortality rate of 7.45 and 7.69/100 person-years (hazard ratio, 0.95 [95% CI, 0.73-1.24]). CONCLUSIONS: No association was found between pLAAO and 1-year mortality, which is consistent with existing evidence from randomized controlled trials. The hdPS approach provides an opportunity to improve nonactive comparator selection in traditional PS analysis.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.003 | 0.003 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
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 teacher head, 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".