Abstract 4357760: Preoperative Daily Step Count and Cognitive Performance Following Cardiac Surgery
Bibliographic record
Abstract
Background: Cognitive decline is a common complication of cardiac surgery, linked to reduced quality of life and increased mortality. Even early, transient deficits are associated with long-term cognitive decline. While several perioperative risk factors have been studied, the role of preoperative physical activity, specifically daily step count, remains underexplored. We evaluated whether a lower preoperative daily step count is associated with postoperative cognitive decline. Hypothesis: Lower preoperative step count is associated with greater risk of cognitive decline following cardiac surgery. Methods: Patients ≥50 years undergoing elective cardiac surgery with cardiopulmonary bypass were prospectively and consecutively enrolled at a single academic medical center between September 2023 and March 2025. Daily step count was measured preoperatively and for the first 90 days after surgery using a commercially available activity tracker. Patients were categorized into two groups based on median preoperative step count: low steps (<6,500 steps/day) and high steps (≥6,500 steps/day). Cognitive performance was assessed using the Montreal Cognitive Assessment (MoCA) preoperatively, at discharge, at 30 days, and 90 days postoperatively. The primary outcome was a decrease in cognitive performance, defined as a MoCA score of ≥1 standard deviation below baseline. Group comparisons were conducted using Wilcoxon rank sum tests for continuous variables and Fisher’s exact tests for categorical variables. Results: We enrolled 24 participants (mean age 66.6±8.7 years; 54% male; 96% white). The median preoperative step count was 5,876 [IQR 4,763–8,781] steps/day, with 58% classified to be in the low steps group. Participants in the low steps group were more likely to be female (p = 0.047), with no other significant demographic or operative differences. Decrease in cognitive performance from baseline at discharge occurred in 50% of participants in the low steps group, compared to 0% in the high steps group (p=0.019), despite similar baseline MoCA scores. No significant group differences were observed in cognitive decline at 30 or 90 days postoperatively, or in recovery of step count by 90 days. Conclusion: Lower preoperative daily step count was associated with increased risk of postoperative cognitive decline at discharge. Daily step count may serve as a simple, scalable target for preoperative intervention to reduce cognitive vulnerability after cardiac surgery.
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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 | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.004 | 0.001 |
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".