Routine use of chest x-ray for low-risk patients undergoing a periodic health examination: a retrospective cohort study
Bibliographic record
Abstract
BACKGROUND: Many evidence-based recommendations advocate against the use of routine chest x-rays for asymptomatic, low-risk outpatients; however, it is unclear how regularly chest x-rays are ordered in primary care. Our study aims to describe the frequency of, and variation in, routine chest x-ray use in low-risk outpatients among primary care physicians. METHODS: In this retrospective cohort study, Ontario residents aged 18 years and older with a periodic health examination (PHE) between Apr. 1, 2010, and Mar. 31, 2015, were identified via administrative claims data. Patients with a recent history (last 3 years) of any of the following were excluded: cardiac or pulmonary disease, high-risk comorbidity (e.g., diabetes), consultations/visits or procedures involving cardiac or pulmonary specialists, cancer and severe chest trauma. The primary outcome, a routine chest x-ray, was defined as at least 1 chest x-ray claim within 7 days after a PHE. RESULTS: While a routine chest x-ray followed only 2.42% of 2 847 508 PHEs, one-quarter of family physicians (499/2031) ordered chest x-rays for more than 5.0% of their PHEs (interquartile range 1.5%-5.0%) and accounted for 62.9% of all tests observed. Routine chest x-ray use declined by 2.0% per quarter (adjusted rate ratio 0.98, 95% confidence interval [CI] 0.97-0.98). Older age (45-64 yr v. 18-44 yr, adjusted odds ratio [OR] 1.82, 95% CI 1.78-1.86; ≥ 65 yr v. 18-44 yr, adjusted OR 2.48, 95% CI 2.39-2.58) and male sex of the patient (OR 2.19, 95% CI 2.14-2.24) and male sex of the provider (OR 1.55, 95% CI 1.51-1.59) were significantly associated with increased odds of a routine chest x-ray being ordered. INTERPRETATION: It is relatively uncommon for a chest x-ray to be ordered as part of a PHE in Ontario; however, the substantial variation observed among physicians suggests potential for interventions targeted at the most frequent users.
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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 | 0.002 | 0.004 |
| Meta-epidemiology (narrow) | 0.000 | 0.001 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.001 | 0.002 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 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 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".