133. A TEN-YEAR RETROSPECTIVE REVIEW OF TEMPORAL ARTERY BIOPSY LENGTHS IN ALBERTA
Bibliographic record
Abstract
Background: Temporal arteritis or giant cell arteritis (GCA) is a large vessel vasculitis that involves extracranial arteries. The historical gold standard for diagnosis is a temporal artery biopsy (TAB) which has potential for false negativity. The purpose of this study is to review all biopsy lengths performed in the province of Alberta, Canada to assess whether an adequate sampling is being performed and to identify predictors of a positive diagnosis of GCA. Methods: A retrospective chart review was performed on patients who had undergone a TAB procedure in 22 sites between January 1st, 2008 to January 1st, 2018. Data extracted included patient’s age sex, levels of inflammatory markers (ESR and CRP), side of biopsy, post-fixation length and final pathological diagnoses. Predictors of positive pathology were modelled using logistic regression. Stata 14.1 (StataCorp) was used for data analysis. Results: A total of 1203 biopsies were identified over the decade. Median age was 73 (quartile range [QR], 64–80) years, with 806 (67%) female patients. A total of 235 (20%) biopsies were diagnosed as GCA, with median biopsy length of 1.3 cm (QR, 0.9–1.8 cm). Biopsy lengths between sites ranged between 0.8 cm (QR, 0.6–1.1 cm) to 2.2 cm (QR, 1.5–3.3 cm). Univariate analysis noted increased age (odds ratio [OR] 1.04 per year, 95% CI, 1.02–1.05; p < 0.001), ESR (OR 1.01 per unit, 95% CI, 1.01–1.02; p < 0.001), CRP (OR 1.01 per unit, 95% CI, 1.01–1.01; p < 0.001) and biopsy lengths (OR 1.25 per cm, 95% CI, 1.06–1.46; p = 0.007) were associated with positive GCA diagnosis. In multivariate analysis, only age (OR 1.04 per year, 95% CI, 1.02–1.05; p < 0.001) and CRP (OR 1.01 per unit, 95% CI, 1.00-1.01; p < 0.001) remained statistically significant predictors of a positive GCA diagnosis. Lastly, we noted increasing odds ratio for obtaining a positive TAB for every increase of 0.5 cm until beyond 2.5 cm which provided minimal additional diagnostic yield. Conclusion: Our study indicates that the length of TABs performed in Alberta is variable and some sites acquire lengths that are less than typically recommended. Age, ESR, CRP and TAB length were significant independent predictors of pathological diagnosis. Lastly, maximal diagnostic yield for a positive biopsy is between 2.0 - 2.4 cm. Disclosures: None
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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 | 0.004 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.005 | 0.007 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.003 | 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".