Atrial fibrillation and frailty related variance in anticoagulation administration among patients with suspected ischaemic heart disease: the AFRAAID, SWEDEHEART study

Background/Introduction

Worldwide, there is a large and growing population of older people, many facing frailty and complex needs. The prevalence of atrial fibrillation (AF), the most common cardiac arrhythmia, increases with age, reaching almost 20% in individuals aged 80 years or older. AF increase the risk of stroke and associated morbidity and mortality, while treatment with oral anticoagulants (OAC) significantly mitigates this risk. Whether treatment patterns differ with degree of frailty, and whether the benefit of OACs are similar in frail and non-frail patients, has not been well studied.

Purpose

To describe antithrombotic treatment in patients with AF, in relation to frailty and to assess differences in the benefit of OAC treatment according to frailty class.

Methods

We used the nationwide quality registry SWEDEHEART to identify all patients with AF, CHA2DS2-VASc ≥1, information on frailty, among patients admitted for suspected myocardial infarction (MI). Data were merged with the Swedish Population Registry and the National Patient Registry for information on comorbidity and outcomes. Based on individual assessment of frailty according to Clinical Frailty Scale (CFS), patients were categorised into four groups. Charlson Comorbidity Index (CCI) was calculated. Exposure was defined as any OAC at discharge, and patients were followed for up to one year. The primary outcome was major adverse cardiovascular events (MACE), a composite of all-cause death, rehospitalisation for MI or stroke. The secondary outcome was net adverse cardiovascular events (NACE), a composite of MACE and major bleeding. Cox regression models were used to adjust for differences in age, sex and comorbidity.

Results

Of the 9489 included patients, 63% were non-frail (CFS 1-3), 19% very mildly frail (CFS 4), 13% mildly to moderately frail (CFS 5-6), and 4% severely frail (CFS 7-9). Frail patients were older, more often women, had more comorbid conditions and higher CHA2DS2-VASc score. Within each frailty category there were minor differences in age, sex and comorbidity. The proportions of patients treated with OAC were similar among those with CFS 1-3, 4 and 5-6, but lower in CFS 7-9 (77%, 78%, 74% and 61%, respectively).

With increasing frailty, we observed an increased one-year risk of MACE: 12%, 23%, 34% and 54% and NACE: 15%, 27%, 37% and 56%, for CFS 1-3, 4, 5-6 and 7-9, respectively. OAC treatment was associated with a lower risk of MACE in all frailty classes: HR (95% CI) 0.86 (0.73-1.02) for CFS 1-3, 0.80 (0.64-0.99) for CFS 4, 0.76 (0.62-0.93) for CFS 5-6 and 0.70 (0.54-0.91) for CFS 7-9. Adjustment for sex, age and CCI strengthened the association. The pattern was similar for NACE (Figure)

Conclusion

In this study of patients with AF and suspected MI, similar proportions were treated with OAC across facility categories, except among the most frail. The benefit associated with OAC treatment appeared similar across frailty categories.Figure