Hospitals vary widely in adhering to aspirin guidelines

There was a 25-fold variation in the proportion of U.S. hospitals that adhered to guidelines about prescribing high-dose aspirin at discharge, with some hospitals discharging fewer than 10% of patients on high-dose aspirin and other hospitals discharging 100% of patients on the regimen, a study found.

Researchers used data from 221,199 patients with myocardial infarction (MI) from 525 U.S. hospitals enrolled from the National Cardiovascular Data Registry's Acute Coronary Treatment and Intervention Outcomes Network Registry-Get with the Guidelines (ACTION Registry-GWTG) to identify patient- and hospital-level factors associated with discharge regimens for aspirin. Currently, clinical trial evidence and current practice guidelines recommend low-dose aspirin (81 mg) after MI. Although aspirin dosing after percutaneous coronary intervention (PCI) largely reflected the guidelines before 2012, the authors explained, high-dose aspirin (325 mg) was prescribed with similar frequency in medically managed patients and those at high risk for bleeding.

Results appeared online Aug. 12 at Circulation: Cardiovascular Quality and Outcomes.

Between January 2007 and March 2011, 60.9% of patients with acute MI were discharged on high-dose aspirin, 35.6% on low-dose aspirin, and 3.5% on other doses. Compared with patients discharged on low-dose aspirin, those discharged on high-dose aspirin were younger and more commonly men and were less likely to have atrial fibrillation, a history of congestive heart failure, stroke, peripheral arterial disease, diabetes, or hypertension. High-dose aspirin was prescribed at discharge to 73.0% of patients who had undergone PCI and to 44.6% of patients managed medically. Among 9,075 patients discharged on aspirin, thienopyridine, and warfarin, 44.0% were prescribed high-dose aspirin. Also, 56.7% of patients with an in-hospital major bleeding event were discharged on high-dose aspirin.

PCI was strongly associated with high-dose aspirin use at discharge, including percutaneous transluminal coronary angioplasty (odds ratio [OR], 2.21; 95% CI, 2.09 to 2.33; P<0.0001); PCI with a bare metal stent (OR, 2.98; 95% CI, 2.87 to 3.08; P<0.0001); or PCI with a drug-eluting stent (OR, 3.06; 95% CI, 2.96 to 3.16; P<0.0001).

Also associated to a lesser extent were age per 5-year increase (OR, 0.93; 95% CI, 0.93 to 0.94; P<0.0001); female sex (OR, 0.88; 95% CI, 0.86 to 0.90; P<0.0001), smoking (OR, 1.06; 95% CI, 1.03 to 1.09; P<0.0001), and presentation with ST-segment elevation MI versus non-ST-segment elevation MI (OR, 1.16; 95% CI, 1.13 to 1.19; P<0.0001).

Compared with aspirin alone, there was a lower likelihood of high-dose aspirin use at discharge for concurrent users of thienopyridine (OR, 0.87; 95% CI, 0.84 to 0.90; P<0.0001), warfarin (OR, 0.31; 95% CI, 0.29 to 0.33; P<0.0001), or thienopyridine plus warfarin (OR, 0.25; 95% CI, 0.23 to 0.26; P<0.0001).

The authors wrote that the wide variability in aspirin dosing across hospitals suggests that local practice habits and uncertainty about appropriate aspirin dosing have a significant influence and that large-scale educational efforts would be needed to change clinical practice.

“Because a major influence of aspirin dosing seems to be hospital-level variation, an important target for rapid quality improvement will be redesigning hospital-based treatment pathways,” the authors wrote. “Adding aspirin dosing to hospital-based quality reports, such as those from the ACTION Registry-GWTG, may be an important strategy to rapidly align practice patterns with the current evidence basis and guideline recommendations.”