Effect of antiplatelet and anticoagulant agents on risk of hospitalizationfor bleeding among a population of elderly nursing home stroke survivors

Background and Purpose-Anticoagulants and antiplatelet agents are underutil ized in the nursing home setting, perhaps because trials demonstrating trea tment efficacy excluded people resembling those with long-term care needs. We sought to quantify the effect of antiplatelet and anticoagulant agents o n risk of hospitalization for bleeding among an elderly nursing home popula tion. Methods-We used a case-control design and identified first hospitalizations for bleeds using Medicare claims data from 1992 to 1997 as potential cases . Cases had at least one minimum data set (MDS) assessment within the 6 mon ths before that hospitalization and a diagnosis of stroke. We identified up to 5 controls residing in the same facility during the same year and quart er as the case with a diagnosis of stroke. Our sample consisted of 3433 cas es and 13 506 controls. Using the MDS, we identified standing orders for as pirin, dipyridamole, ticlopidine, or warfarin and used conditional logistic regression modeling to estimate the effect of these agents on risk of hosp italization for a bleed. Results-After adjustment, use of warfarin (odds ratio [OR], 1.26; 95% CI, 1 .11 to 1.43) and combination therapy (OR, 1.34; 95% CI, 0.99 to 1.82) were associated with an increased risk of hospitalization for a bleed compared w ith nonusers. The odds of aspirin use was greater among cases than controls (OR, 1.07; 95% CI, 0.96 to 1.18) after adjustment. Conclusions-Although present, the risk associated with use of these agents is small. The numbers needed to treat to harm 1 resident with aspirin and w arfarin were 467 and 126, respectively.