The Impact of US FDA and Health Canada Warnings Related to the Safety of High-dose Simvastatin
Bibliographic record
Abstract
INTRODUCTION: Between 2010 and 2012, the US Food and Drug Administration and Health Canada issued warnings to healthcare professionals emphasizing the increased risk of muscle problems with high-dose simvastatin. OBJECTIVE: To measure the impact of the Health Canada safety warning regarding dose-dependent adverse effects of simvastatin on prescribing of low, medium, and high doses of simvastatin. METHODS: An interrupted time-series design was used to evaluate the impact of a Health Canada safety warning on 7 November 2012 regarding the safety of high-dose simvastatin. Monthly prescription records were analyzed for beneficiaries of the Nova Scotia Seniors' Pharmacare Program aged 65 years or older who had received > 1 prescription of simvastatin between 1 January 1997 and 31 March 2015. Autoregressive Integrated Moving Average models were used to test changes in the proportion of beneficiaries dispensed a low dose (< 40 mg), medium dose (40 mg to < 80 mg), or high dose (≥ 80 mg) of simvastatin over time. RESULTS: There were 219 monthly periods, of which 29 periods occurred after the Health Canada warning. On average during the pre-warning periods there were 2944 simvastatin users per month, of whom 71% were dispensed a low dose, 26% a medium dose, and 2% a high dose. The proportion of beneficiaries dispensed low-dose simvastatin increased by 0.9% (one-sided p value 0.035; 90% CI 0.07-1.65), the proportion dispensed medium-dose simvastatin decreased by 0.7% (one-sided p value 0.0496; 90% CI -1.48 to -0), and there was no significant change in the proportion dispensed high-dose simvastatin (-0.15% change, one-sided p value 0.205; 90% CI -0.45 to 0.15). CONCLUSIONS: The Health Canada Health Care Professional warning had a small effect on increasing the proportion of beneficiaries dispensed low and medium doses of simvastatin but not high doses of simvastatin. Nevertheless, there remain seniors in Nova Scotia receiving high-dose simvastatin for whom the benefit/risk potential may need to be re-evaluated.
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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 | 0.013 | 0.094 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| 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) | 0.003 | 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".