Should patients with higher blood pressure variability be excluded from validation studies? An assessment of the ‘12/8’ rule
Bibliographic record
Abstract
To limit the inclusion of participants with increased blood pressure (BP) variability and presumably to avoid potential bias, the International Standards Organization BP device validation standard recommends exclusion of patients with a BP variability of more than 12/8 mmHg across reference readings. This '12/8 rule' is based on expert consensus and lacks empirical justification. In a post-hoc analysis of a study comparing two types of cuff designs carried out according to the International Standards Organization standard, we divided the study sample into patients who did not have (n=79) and patients who had (n=55) more than 12/8 mmHg variability. Patients with more than 12/8 mmHg variability were older and had a higher prevalence of diabetes (41.8 vs. 22.8%; P=0.02) and hypertension (43.6 vs. 29.1%; P=0.08). The mean systolic BP differences between the two cuff designs were not significantly different in participants who did not show more than 12/8 mmHg variability versus those who did (2.2±3.5 vs. 3.1±3.4; mean difference of differences -0.9±3.4; P=0.14). Similarly, the mean diastolic BP differences were not significantly different in participants who did not have more than 12/8 mmHg variability versus those who did (1.5±2.2 vs. 1.4±2.6; mean difference of differences 0.1±2.4; P=0.82). A limitation of our analysis is that the original study data focused on a comparison of different cuff designs and not formal validation of a specific device. Therefore, replication of these findings is warranted. Nevertheless, our findings do not support the use of the 12/8 rule and indicate that this rule may be promoting unnecessarily homogenous study samples, limiting external generalizability, and needlessly increasing workload and expense.
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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 | 0.626 | 0.674 |
| Meta-epidemiology (narrow) | 0.002 | 0.002 |
| Meta-epidemiology (broad) | 0.006 | 0.006 |
| Bibliometrics | 0.004 | 0.003 |
| Science and technology studies | 0.004 | 0.006 |
| Scholarly communication | 0.007 | 0.007 |
| Open science | 0.010 | 0.005 |
| Research integrity | 0.011 | 0.008 |
| Insufficient payload (model declined to judge) | 0.001 | 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; the direct Gemma label and the distilled Codex classifier agree on what is shown here.
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".