NEW YORK (Reuters Health) – Superficial, or “nuisance,” bleeding troubled more than a quarter of patients on dual-antiplatelet therapy following the implantation of drug-eluting stents, according to new research. And it affects compliance.

The bleeding afflicted 28.9% of the patients taking clopidogrel and aspirin for one year, and 5.7% of those stopped taking one or both of the drugs in a new study published in the May edition of the American Heart Journal.

“Nuisance bleeding should be included as a safety parameter in pivotal clinical trials assessing new antiplatelet agents,” because of its prevalence and associated drug non-compliance, Dr. Ron Waksman and colleagues at the Washington Hospital Center in Washington, D.C. wrote.

Their study included 2,948 patients, all of whom received drug-eluting coronary stents. Afterward, doctors prescribed aspirin (325mg/day) indefinitely and clopidogrel (300-600mg/day) for at least six months but recommended for up to one year.

After excluding nine (0.3%) patients with major bleeding, they were left with 2,811 patients: 812 (28.9%) who had nuisance bleeding, which included easy bruising and bleeding from small cuts, and 1,999 (71.1%) with no bleeding. Nuisance bleeding occurred daily in 569 patients, weekly in 32, monthly in 73, and a single time in 138.

On univariate analysis, the researchers identified two risk factors for nuisance bleeding on clopidogrel: Caucasian race (OR: 2.0, p < 0.001) and renal failure (OR: 1.01, p = 0.008). Age, body mass index, and a history of diabetes were each negatively associated with nuisance bleeding. On multivariate analysis, however, only Caucasian race was an independent predictor of nuisance bleeding. At one year, the nuisance bleeding group had a higher rate of major adverse cardiovascular events (9.4% vs. 6.7%; p=0.02). There was no significant difference in rates of death or stent thrombosis. Two-year follow-up showed similar results. “The incidence of nuisance bleeding was very high in our study,” the authors said. “Given the emergence of more potent antiplatelet drugs such as prasugrel, which has increased bleeding complications compared to clopidogrel, these nuisance bleeding rates may become even higher.” References:
Am Heart J 2010;159:871-875.