DAPT for secondary prevention of AIS

Dual antiplatelet therapy for secondary prevention in ischemic stroke –Trends in prescription patterns after pivotal trials and guideline updates.

Key Takeaway

The publication of 2 pivotal trials (CHANCE and POINT) and serial AHA/ASA guideline updates showed:

• Increased adoption of DAPT for secondary prevention in:

  • Minor ischemic strokes (for which guidelines recommended DAPT use)

  • Nonminor ischemic strokes (for which the riskbenefit ratio of DAPT has not been fully established)

• Underuse of DAPT in patients with minor ischemic stroke (53.0% patients did not receive) despite class I, level A evidence recommendation

The findings suggest an important opportunity to improve adherence to evidence based antiplatelet therapy for secondary prevention in AIS.

Why This Matters

• Recommendations for DAPT (aspirin and clopidogrel) for secondary prevention in AIS have evolved over time*, but the degree to which physicians follow them in routine clinical practice is unknown.
• This study evaluated the antiplatelet prescription patterns at discharge in patients with AIS after the release of pivotal trials and serial AHA/ASA guideline updates in the US.

Study Design

Assessment of antiplatelet prescriptio

1. Before CHANCE trial
2. Before 2014 AHA/ASA guideline updates
3. Before POINT trial and 2018 AHA/ASA guideline updates
4. Before 2019 AHA/ASA guideline updates
5. After 2019 AHA/ASA guideline updates

Antiplatelet agent categorizatio

1. Aspirin monotherapy
2. Clopidogrel bisulfate monotherapy
3. DAPT of aspirin and clopidogrel
4. Aspirin and dipyridamole
5. Other antiplatelet agents^‡

Analyses

• Proportions of antiplatelet medication over time were evaluated by the Cochran-Armitage test for trend.
• Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) reporting guideline was followed.
• Two-sided P <0.05 was considered as statistically significant.

Key results

Patient characteristics
Number of patients	1,281,034
Mean age (IQR)	68 (59-78) years
Men/Women	51.2% / 48.8%
Asian	3.1%
HISPANIC	7.9%
Non-hispanic black	20.8%
Non-hispanic white	64.1%
Other race	4.1%
Patients receiving antiplatelet therapy at discharge	Aspirin monotherapy = 54.5% Clopidogrel monotherapy = 12.4% DAPT = 30.8% Aspirin and dipyridamole = 1.8% Other antiplatelet agents or combination = 0.6%

Prescription patterns of DAPT
	Before chance trial (N=106,725)	Before 2014 AHA/ASA guideline updates (N=76,357)	Before point trial and 2018 AHA/ASA guideline updates (N=653,883)	Before 2019 AHA/ASA guideline updates (N=302,818)	After 2019 AHA/ASA guideline updates (N=141,251)
Use of DAPT	19.4%	23.1%	27.6%	37.2%	44.9%
Use of DAPT in minor strokes (NIHSS score ≤ 3)	19.5%	23.6%	28.1%	38.3%	47.0%
Use of dapt in nonminor strokes (NIHSS score > 3)	19.4%	22.8%	28.0%	36.5%	42.6%

Use of dapt after 2019 AHA/ASA guideline updates

• Potential underuse in patients with minor strokes: 53.0% (95% CI: 52.7%–53.4%) did not receive DAPT • Potential overuse in patients with nonminor ischemic stroke: 42.6% (95% CI: 42.1%–43.0%) received DAPT

Limitations

• Lack of documented reasons for:

  • Prescribing or not prescribing DAPT

  • Timing of the initiation

  • Duration of antiplatelet treatment

  • Generalizability to patients treated at non-registry hospitals or in other countries

• Lack of information on prescribing trends post June 2020

* CHANCE and POINT trials showed short-term use of DAPT (21–90 days) to be effective in reducing the risk of recurrent ischemic stroke in patients with minor ischemic stroke; AHA/ASA updated recommendations for DAPT in routinesecondary prevention after ischemic stroke from “risk ≥ benefit” (class III) in 2011, to “benefit >>> risk” (class I, level ofevidence A) in 2019

^† Between October 1, 2012, and June 30, 2020
^‡ Ticlopidine hydrochloride, prasugrel, ticagrelor monotherapy, or their combination with aspirin

MAT-BH-2300013/V1/JAN2023