In CKD Patients with AF, Anticoagulation Increases Risks

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In older adults with chronic kidney disease (CKD), new anticoagulant therapy for atrial fibrillation (AF) is associated with increased risks of ischemic stroke and hemorrhage, reports a study in the British Medical Journal.

From a UK general practice database, the researchers identified 6977 CKD patients newly diagnosed with AF. Of these, 2434 were started on anticoagulation within 60 days. Propensity scores were used to create matched pairs of patients, exposed or not exposed to anticoagulant therapy. Mean age was about 82 years. At a median follow-up of 506 days, rates of ischemic stroke, cerebral or gastrointestinal bleeding, and death from any cause were compared between groups.

The crude rate of ischemic stroke was 4.6 per 100 person-years after starting anticoagulants, compared to 1.5 for matched patients not taking anticoagulants. Rates of hemorrhage were 1.2 versus 0.4 per 100 person-years, respectively. Both adverse outcomes were significantly increased in the anticoagulant group: hazard ratio 2.60 for ischemic stroke and 2.42 for hemorrhage. All-cause mortality was paradoxically lower for patients starting anticoagulants: hazard ratio 0.82.

About one-third of patients with CKD also have AF. Decisions about anticoagulant therapy are complicated by the fact that stroke and bleeding risk both increase progressively as kidney function declines.

The results show increased rates of ischemic stroke and cerebral or gastrointestinal hemorrhage in older CKD patients who start anticoagulants after being diagnosed with AF. The reasons for the unexpected reduction in mortality are unclear. “These paradoxical findings emphasise the urgent need for adequately powered randomised controlled trials to provide clarity on correct clinical management,” the researchers conclude [Kumar S, et al. Ischaemic stroke, haemorrhage, and mortality in older patients with chronic kidney disease newly started on anticoagulation for atrial fibrillation: a population based study from UK primary care. BMJ 2018; 360:k342].