Relationship between the Ratio of Red Cell Distribution Width to Albumin and 28-Day Mortality among Chinese Patients over 80 Years with Atrial Fibrillation

Abstract

<b><i>Introduction:</i></b> Atrial fibrillation (AF) is a prevalent heart arrhythmia in elderly adults aged 80 years or older. The red cell distribution width (RDW) to albumin ratio has been acknowledged as a reliable prognostic marker for poor outcomes in a variety of disorders. However, there exists limited scientific evidence on the association of RDW to albumin (RAR) with mortality in geriatric individuals with AF. <b><i>Methods:</i></b> From January 2015 to June 2020, a retrospective study was conducted in a tertiary academic institution that diagnosed 1,141 elderly adults with AF. The RAR value was calculated as the ratio of RDW (%) to albumin (g/dL). The potential association between RAR and cardiovascular mortality and the risk of all-cause mortality within 28 days was evaluated by means of multivariable Cox regression analysis. <b><i>Results:</i></b> The 28-day all-cause and cardiovascular mortality rates were 8.7% and 3.3%, respectively. Increased RAR tertiles were found to be significantly associated with greater all-cause mortality (T1: 1.6%; T2: 6.2%; T3: 18.1%, <i>p</i> &lt; 0.001) and cardiovascular mortality (T1: 0.8%; T2: 2.9%; T3: 6.3%, <i>p</i> &lt; 0.001) using Kaplan-Meier analysis. Continuous RAR had a positive association with all-cause mortality (hazard ratios [HR] = 1.42, 95% confidence interval [CI] 1.23–1.65) and cardiovascular mortality (HR = 1.31, 95% CI: 1.05–1.64), even after accounting for numerous confounding variables. In comparison to the T1 group, individuals with the highest RAR levels displayed a greater risk of all-cause mortality (HR = 2.73, 95% CI: 1.11–6.74) and cardiovascular mortality (HR = 2.59, 95% CI: 0.69–9.78). Increased RAR levels were related to higher rates of cardiovascular and all-cause mortality across almost all subgroups. <b><i>Conclusion:</i></b> RAR is independently correlated with 28-day all-cause mortality and cardiovascular mortality in AF-affected individuals aged ≥80.