Comparison of incidence, predictors, and the impact of co-morbidity and polypharmacy on the risk of recurrent syncope in patients <85 versus ≥85 years of age

Abstract

Recurrent syncope is a major cause of hospitalizations and may be associated with cardiovascular co-morbidities. Despite this, prognostic factors and the clinical characteristics among patients are not well described. Therefore, we identified and analyzed data on all patients >50 years of age discharged after a first-time episode of syncope in the period 2001 to 2009 through nationwide administrative registries. We identified the clinical characteristics of 5,141 patients ≥85 years of age and 23,454 patients <85 years of age. Multivariate Cox models were used to assess prognostic factors associated with the end point of recurrent syncope according to age. We found that those with syncope and ≥85 years were more often women (65% vs 47%) and generally had a greater prevalence of noncardiovascular co-morbidities, whereas the prevalence of cardiovascular co-morbidities was more heterogeneously distributed across age groups. Overall, significant baseline predictors of recurrent syncope were aortic valve stenosis (hazard ratio [HR] 1.48, 95% confidence interval [CI] 1.31 to 1.68), impaired renal function (HR 1.34, 95% CI 1.15 to 1.58), atrioventricular or left bundle branch block (HR 1.32, 95% CI 1.16 to 1.51), male gender (HR 1.18, 95% CI 1.12 to 1.24), chronic obstructive pulmonary disorder (HR 1.10, 95% CI 1.02 to 1.19), heart failure (HR 1.10, 95% CI 1.02 to 1.21), atrial fibrillation (HR = 1.09, 95% CI 1.01 to 1.19), age per 5-year increment (HR 1.09, 95% CI 1.07 to 1.10), and orthostatic medications per increase (HR 1.06, 95% CI 1.03 to 1.09). Atrial fibrillation and impaired renal function both exhibited less prognostic importance for recurrent syncope in the elderly compared with younger population (p for interactions <0.01). In conclusion, predictive factors of recurrent syncope were closely associated with increased cardiovascular risk profile age and gender. The use of multiple orthostatic medications additively increased the risk of recurrences representing a need for strategies to reduce unnecessary polypharmacy.