Stroke and mortality in patients with incident heart failure: the Diet, Cancer and Health (DCH) cohort study

Abstract

Objective: The objective was to test the hypothesis that the risk of stroke, death and the composite of 'stroke and death' would be increased among patients with incident heart failure (HF). While HF increases the risk of mortality, stroke and thromboembolism in general, the 'extreme high-risk' nature of incident HF is perhaps under-recognised in everyday clinical practice.

Design: Prospective cohort study.

Setting: Large Danish prospective epidemiological cohort.

Participants: Subjects in the Diet, Cancer and Health study.

Outcome measures: Stroke, death and the composite of 'stroke and death' among patients with incident cases of HF, without concomitant atrial fibrillation.

Results: From the original cohort, 1239 patients with incident HF were identified. Incidence rates show a higher incidence in the initial period following the diagnosis of HF, with a markedly higher rate of death and stroke (ischaemic or haemorrhagic) in the initial 30 days following the diagnosis of incident HF. While lower than the risk at 0-30 days, the higher risk did not return to normal at 6+ months after the diagnosis of incident HF. This risk increase was apparent for the end points of stroke (ischaemic or haemorrhagic or both) whether or not a vitamin K antagonist (VKA) was used. With VKA use, there was a lower adjusted HR for death and the composite of 'death or stroke' compared to non-VKA use at the three time intervals following diagnosis of HF, whether 0-30 days, 30 days to 6 months and 6+ months. On multivariate analysis, previous stroke/transient ischaemic attack/thromboembolism was a predictor of higher risk of stroke, death and the composite of 'stroke and death', while VKA treatment was a highly significant predictor of a lower risk for death (adjusted HR 0.46, 95% CI 0.28 to 0.74, p<0.001) and the combined end point of death or stroke (adjusted HR 0.64, 95% CI 0.43 to 0.96, p=0.003).

Conclusions: Based on relative hazards, incident HF is clearly a major risk factor for stroke, death and the composite of 'stroke and death', especially in the initial 30 days following initial diagnosis. The use of VKA therapy was associated with a lower risk of these end points. These findings would have major implications for the approach to management of patients presenting with incident HF, given the high risk of this population for death and stroke, which may be ameliorated by VKA therapy.

Figure 1

Flowchart describing case exclusion for the two data sets used for analysis. DCH, Diet, Cancer and Health; HF, heart failure.

Figure 2

Hazard rate ratios of time after incident heart failure (HF) relative to non-HF exposed. VKA, vitamin K antagonist.

Figure 3

Baseline survival curve for heart failure (HF) patients, time (years) since incident HF. Additionally the cumulative incidence rate of HF events that required rehospitalisation.