A population based cohort study: the epidemiology of pediatric venous thromboembolism in Quebec, Canada
Bibliographic record
Abstract
Background: Pediatric venous thromboembolism (VTE), although rare, is associated with significant morbidity and mortality. Published incidence and recurrence rates in children vary widely with incidence rates ranging from 0.07 to 0.49 VTE per 10 000 children/year and recurrence risks ranging from 5.5% to 18.5%. There is currently a paucity of studies evaluating temporal incidence trends, as well as risk factors for recurrence. Objectives: To describe the age-adjusted incidence rate of pediatric VTE and its trend over time, to determine VTE recurrence rate and overall all-cause mortality following VTE, and to determine predictors of VTE recurrence and all-cause mortality. Methods: A retrospective population-based cohort of all children (ages 1-17 inclusive) with a first time diagnosis of VTE in the province of Quebec between January 1st, 1994 and December 31st, 2004 was obtained from a comprehensive administrative hospital database (Med-Echo). Provincial census estimates were used to calculate age-standardized incidence rates (IR) of pediatric VTE. The incidence rate trend was then analyzed over the eleven-year study period using Poisson linear regression with time as both a continuous (yearly) and categorical (time periods) variable. Rate of VTE recurrence and all-cause mortality were determined. Univariate Cox-proportional hazards models and log rank testing were used to assess which risk factors would be incorporated into the final multivariate Cox-proportional hazards model evaluating risk of VTE recurrence and all-cause mortality. Results: In total, 487 incident cases of VTE in children 1-17 years of age were documented. Based on the estimated provincial census person-years during the study period, the age-standardized IR was 0.29 VTE per 10 000 person-years (95% confidence interval (CI) 0.26-0.31). Females had a statistically significant higher VTE incidence rate (per 10 000 person-years) than males, 0.37 and 0.21 per 10 000 person-years, respectively with an incidence rate ratio comparing females to males, adjusted for age group of 1.75 (95% CI 1.46-2.10). Trend analysis showed no statistically significant change in the age-standardized IRs over the 11-year period. The VTE recurrence rate was 2.77 (95% CI 2.2-3.4) per 1000 person-months (overall risk of 16%). Recurrence was associated with the presence of a chronic disease, defined as a diagnosis of inflammatory bowel disease, cystic fibrosis, lupus, sickle cell disease or nephrotic syndrome, (hazard ratio (HR) 2.3; 95% CI 1.2-4.3), presence of a central vascular line at time of initial VTE (HR 1.9; 95% CI 1.0-3.3) and portal vein thrombosis as the initial VTE presentation (HR 4.1; 95% CI 1.5-11.0). Overall all-cause mortality was 6.4%, hazard modeling of known risk factors for VTE was inconclusive for mortality. Conclusions: Pediatric VTE is more frequent than previously described, however its incidence appears to be stable over time. Females are more prone to VTE than males in this age group. Risk of recurrence in our cohort is at the higher end of previously reported values, and is higher in those with a pre-existing chronic illness, central vascular line or with an initial diagnosis of portal vein thrombosis. All-cause mortality was lower in our cohort than previous large studies of VTE in this age group. Our findings highlight the need for future studies to address sex differences in the incidence of pediatric VTE to help determine effective primary thromboprophylaxis strategies in children at high risk for VTE, as well as determine effective secondary prophylaxis strategies in children at high risk for VTE recurrence.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.005 |
| Science and technology studies | 0.002 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 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".