Frailty in patients affected by atrial fibrillation

Abstract

Atrial fibrillation (AF) is the most common arrhythmia among elderly people. However its relationship with the frailty syndrome is not well understood. It has been suggested that AF may be a marker of frailty in elderly, leading to the loss of independence in performing of routine daily activities. The aim of this study is to investigate the association between AF, frailty and cognitive decline in elderly patients. A total of 140 hospitalized patients, mean age 79.2 ± 7.4 years were enrolled in our study. Of these, 70 were affected by parossistic, persistent or permanent AF and 70, matched for age and gender, were concurrently studied as control. Cognitive impairment and frailty state has been evaluated in each patient using the Mini Mental State Examination (MMSE) and a standard score of accumulated deficits for constructing a frailty index. We have observed a higher number of frail patients in the AF group as compared with controls (88.6% vs 67.1%, p = 0.004). The group of patients with frailty syndrome had MMSE score significantly lower than those of the nonfrail group (16.8 ± 9.8 vs 22.2 ± 6.4, p = 0.005). Furthermore, a negative correlation between MMSE score and frailty index (rho = −0.517, p < 0.001) has been shown. Our study points out a statistical association between frailty and AF. Atrial fibrillation could worsen the frailty state, but perspective studies are necessary to confirm an increased mortality in patients affected by AF and frailty.

Introduction

AF is prevalent in older people (Sudlow, Thomson, Thwaites, Rodgers, & Kenny, 1998). Approximately 70% of affected patients are between the ages of 65 and 85 years; about 10% of patients are older than 80 years (Go et al., 2001, Sudlow et al., 1998). AF is often associated with cardiovascular diseases (CVD) and noncardiovascular diseases such as hypertension, heart failure, coronary artery disease, cardiomyopathies, valvular heart disease, diabetes mellitus, pulmonary and thyroid disease (Feinberg, Blackshear, Laupacis, Kronmal, & Hart, 1995). The elderly with AF show a significant increase in morbidity and mortality related not only to hemodynamic impairment and thromboembolic events (Benjamin et al., 1998) but also to increased hospitalization rate, multiple comorbidities and adverse drug events (Chrischilles et al., 1992, Moore et al., 1998, Wattigney et al., 2002).

A relationship between AF and impairment of cognitive functions is a matter for debate. Some studies do not report an association between these two pathologies (Kwok et al., 2011, O’Connell and Gray, 1992, Park et al., 2007). On the contrary, more recent researches have detected a significant association between AF and cognitive decline as measured by mental performance tests (Marzona et al., 2012, Sabatini et al., 2000). The impairment of cognitive functions is a key point of frailty syndrome which is characterized by decreased reserves in multiple organ systems (Clegg & Young, 2011). Frailty is believed to develop as a consequence of a decline in several physiological systems, which collectively results in a vulnerability to sudden health state changes triggered by relatively minor stressor events (Ahmed, Mandel, & Fain, 2007). Epidemiological studies have shown that frailty incidence is related to age, reaching more than 32% in elderly people older than 90 years. In particular, 3–7% of elderly people between the ages of 65 and 75 years are frail and about 7% of the people older than 65 years and the 20% of elderly more than 80 years, but without diseases, have frailty syndrome (Ahmed et al., 2007) and it is proved that frailty increases steadily with age, from about 4% at 65–69 years old to about 26% at 85 years old or older (Song, Mitnitski, & Rockwood, 2010).

Studies performed in the cardiovascular field have shown that heart failure, blood hypertension, low HDL values and higher levels of abdominal fat are associated with an increased likelihood of frailty (Bastos-Barbosa et al., 2012, Newman et al., 2001). Despite controversial, there is evidence that both blood hypertension and hypotension, two pathologies commonly observed in older people, could be risk factors for frailty development (Bastos-Barbosa et al., 2012, Fattori et al., 2013, Lee et al., 2011, Molander et al., 2008).

The relationship between frailty and AF is under investigation. Fumagalli et al. (2010) have suggested that AF may be a marker of frailty in the elderly and Marzona et al. have reported a loss of independence in performing activities of daily living in a follow-up of AF elderly patients (Marzona et al., 2012). Frailty can be evaluated in many ways and several indices have been proposed for frailty diagnosis (Fried et al., 2001, Rockwood et al., 2005). Criteria considered by Fried et al. include shrinking (weight loss), weakness (handgrip strength), poor endurance (self-reported exhaustion), slowness (gait speed), and low physical activity level (kilocalories expended per week). The frailty score of Fried comprises a possible range from 0 to 5. An older person is considered frail if three or more criteria are assessed as positive. Individuals who do not meet any of these criteria are regarded as not being frail, whereas people with one or two positive criteria are considered to be pre-frail (Fried et al., 2001). The Clinical Frailty Scale proposed by Rockwood et al., which underlines the importance of deficits accumulation and losses of physiological reserves in frailty syndrome, is based on clinical judgment, ranging from 1 (robust health) and 7 (complete functional dependence on others) (Rockwood et al., 2005). Searle et al. have recently proposed a standard procedure for constructing a frailty index in order to quantify frailty related health characteristics and outcomes in older adults (Searle, Mitnitski, Gahbauer, Gill, & Rockwood, 2008). The aim of our study was to investigate the association between AF, frailty and cognitive impairment in elderly patients affected by AF using the standard procedure for creating a frailty index suggested by Searle et al. (2008).