Abstract 2292: Dipyridamole Induced Headache Indicates Lower Recurrence Risk in Secondary Prevention of Ischemic Stroke
Bibliographic record
Abstract
Background Headache is a common adverse event in patients treated with dipyridamole (DP) for secondary stroke prevention. The headache resembles migraine, possibly indicating that vessel walls and endothelium of cerebral vessels are still intact and able to dilate. Purpose We hypothesized that patients who develop headache on DP will have a lower risk of recurrent stroke compared to patients without headache. Methods We analysed data from PROFESS (N=20,332) comparing aspirin plus DP with clopidogrel. Prospective data on headache as an adverse event within 7 days of start of medication or reason for discontinuation of study drug and recurrent stroke incidence were collected. We compared the relative risk of recurrent stroke in patients who did and did not get headache and who did or did not discontinue study medication due to headache. Analyses were repeated in the smaller ESPS 2 study (N=6,602) investigating aspirin, aspirin plus DP, DP or placebo in secondary stroke prevention. Results In PROFESS 3067 patients taking aspirin plus DP complained of headache in the first 7 days while 6988 did not. In the aspirin plus DP group, the recurrent stroke risk after 2.5 years was 8.2% in patients with and 9.4% in patients without headache resulting in a RR of 0.90 (95% CI 0.81-1.01, p= 0.07). In the clopidogrel treated group there was no difference in stroke risk between patients with and without headache RR = 1.00 (95% CI 0.82-1.23). In PROFESS, 518 patients taking aspirin plus DP discontinued treatment due to headache in the first 90 days. Their risk of recurrent stroke was 5.0%. In patients who did not discontinue aspirin plus DP due to headache in the first 90 days, the recurrent stroke risk was 9.2% resulting in a RR of 0.53 (95% CI 0.36-0.79, p=0.001). In the clopidogrel treated patients the RR was 0.89(95% CI 0.36-2.20); 7.9% of 63 clopidogrel patients who discontinued due to headache within 90 days of randomization had stroke vs. 8.9% in all other patients. In ESPS 2, 129 patients taking aspirin plus DP discontinued treatment due to headache in the first 90 days. Their rate of recurrent stroke was 6.2%. In patients who did not discontinue aspirin plus DP due to headache in the first 90 days, the recurrent stroke rate was 9.8% resulting in a RR of 0.63 (95% CI 0.31-1.26, p=0.18). Conclusions In PROFESS patients who developed headache on aspirin plus DP for secondary stroke prevention had a reduced risk of stroke recurrence in comparison with those who did not or were treated with clopidogrel. These results are directionally supported by similar but non-significant findings on treatment discontinuation of aspirin plus DP in ESPS 2. Headache in clopidogrel treated patients did not demonstrate any protective effects, suggesting specificity. These results suggest that DP-induced headache may be a marker for more reactive vessel walls in cerebral arteries.
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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 | 0.005 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.002 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.011 | 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".