From geriatric assessment to inflammation. A pilot, observational, study about frailty components in older patients with persistent atrial fibrillation

Abstract

Background: Atrial fibrillation (AF) is the most common arrhythmia diagnosed at an older age. AF is associated with frailty, a condition possibly justifying the higher rate of complications and mortality in aged individuals. This study was aimed at describing the characteristics correlated to frailty in older AF subjects.

Methods: After having excluded a < 3 months major surgery procedure, cancer or other conditions associated with activation of inflammation, and a life expectancy < 12 months, we consecutively enrolled patients ≥ 65 years with persistent AF. They underwent a Comprehensive Geriatric Assessment evaluation. In particular, Mini-Mental State Examination, 15-item Geriatric Depression Scale and Short-Physical Performance Battery (SPPB) described, respectively, cognitive profile, depressive symptoms and physical performance. A venous blood sample was collected to measure interleukin-6 (IL-6; marker of low-grade inflammation) and acylcarnitines, expression of mitochondrial dysfunction and abnormal energy production.

Results: Overall, 49 patients (mean age: 76 ± 6 years; women 30.6 %) were studied. Cluster analysis described two different patterns; the second (N = 18, 36.7 %), when compared to the first one (N = 31, 63.3 %), was characterized by a worse phenotype, identified by the simultaneous presence of lower body mass index, higher CHA₂DS₂-VASc score (index of clinical complexity), worse SPPB functional performance, and high IL-6 levels. Second cluster patients had a higher concentration of 13 of the 35 acylcarnitines evaluated and increased 5-year mortality. All these features can outline a frail condition.

Conclusions: Body size, clinical complexity, physical performance and low-grade inflammation seem to rapidly and adequately describe frailty.

Keywords: Acylcarnitines; Atrial fibrillation; Frailty; Inflammation; Older patients; Physical performance.

Fig. 1

(Panel A) Graphical representation of the inverse association between IL and 6 and SPPB scores; the better the physical performance, the lower the cytokine concentration. (Panel B) Different levels of C12:1 and C18:1 acylcarnitines by cluster of older AF patients. The concentration is significantly higher in subjects with the worse phenotype.

Fig. 2

(Panel A) Kaplan-Meier analysis of survival by cluster; at the follow-up evaluation, patients with the better phenotype – blue line − are characterized by lower all-cause mortality than the worse phenotype subjects – burgundy line. (Panel B) The four variables associated with cluster definition (i.e., low BMI, CHA₂DS₂-VASc and SPPB scores, and IL-6), also reciprocally interacting, could cause the frail status in older patients with persistent atrial fibrillation. Abbreviations. BMI: body mass index; CHF: chronic heart failure; IL-6: interleukin-6; TIA: transient ischaemic attack; SPPB: Short-Physical Performance Battery; TEE: thrombo-embolic event.