Patterns of Antipsychotic use Among Community-Dwelling Elderly Patients with Dementia: Impact of Regulatory Warnings
Bibliographic record
Abstract
Purpose: In Canada, regulatory warnings on cerebrovascular effects of risperidone and olanzapine in the elderly population with dementia were issued, respectively, in 2002 and 2004, and those on mortality associated with all atypical antipsychotics (APs) in 2005. These warnings led to a decrease in the prescription of APs, but effects on patterns of usage remain poorly examined. We conducted a study to assess the association between warnings and patterns of AP use in a population of community-dwelling elderly with dementia. Methods: A retrospective cohort of 10,969 community-dwelling elderly (age 66+) with dementia who were new users of APs between 1st January 2000 and 31st December 2009 was assembled through the Quebec drug claims database (RAMQ). Association between regulatory warnings and rate of initiation of AP treatment was evaluated through interrupted time series analysis. Effects of the 2005 warning on cerebrovascular history in treated patients, and AP usage patterns (dosage, duration) were assessed, respectively through multivariate logistic regression and multiple linear regression analysis. Results: The proportion of AP treatments initiated with risperidone decreased over time while that of quetiapine increased and of olanzapine remained stable. Controlling for covariates, the cerebrovascular risk profile of treated patients did not change after the 2005 warning (OR=1.05, 95%CI: 0.90 – 1.22). A small decrease in mean prescribed daily dose for risperidone was observed after the 2005 warning (-0.05 mg, p<0.001) while an increase was observed for olanzapine (+0.34 mg, p=0.009) and quetiapine (+1.27 mg, p=0.40). No change in treatment duration was observed (p=0.19). Conclusion: Although regulatory warnings led to a decrease in the use of atypical APs, these products are still widely prescribed off-label in the elderly population with dementia. Channelling of APs toward patients with lower cerebrovascular risks and changes in prescription practices were not apparent after the warnings
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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 | 0.005 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.002 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.000 |
| 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".