Identifying a high stroke risk subgroup in individuals with heart failure.

Background: Heart failure (HF) is associated with an overall stroke rate that is too low to justify anticoagulation in all patients. This study was conducted to determine if vascular risk factors can identify a subgroup of individuals with heart failure with a stroke rate high enough to warrant anticoagulation.

Methods: The REGARDS study is a population-based cohort of US adults aged ≥45 years. Participants are contacted every 6 months by telephone for self- or proxy-reported stroke and medical records are retrieved and adjudicated by physicians. Participants were characterized into 3 groups: HF without atrial fibrillation (AF), AF with or without HF, and neither HF nor AF. Cardiovascular risk factors at baseline were compared between participants with and without incident stroke in HF and AF. Stroke incidence was assessed in risk factor subgroups in HF participants.

Results: Of the 30,239 participants, those with missing/anomalous data were excluded. Of the remaining 28,832, 1360 (5%) had HF without AF, 2528 (9%) had AF, and 24,944 (86%) had neither. Previous stroke/transient ischemic attack (TIA; P = .0004), diabetes mellitus (DM; P = .03), and higher systolic blood pressure (P = .046) were associated with increased stroke risk in participants with HF without AF. In participants with HF without AF, stroke incidence was highest in those with previous stroke/TIA and DM (2.4 [1.1, 4.0] per 100 person-years).

Conclusions: The combination of previous stroke/TIA and DM increases the incidence of stroke in participants with HF without AF. No analyzed subgroup had a stroke rate high enough to make it likely that the benefits of warfarin would outweigh the risks.