Orthostatic hypotension and long-term incidence of atrial fibrillation: the Malmö Preventive Project.

OBJECTIVES: Orthostatic hypotension (OH), a common manifestation of autonomic dysfunction, has been identified as an independent risk factor for all-cause mortality and incident cardiovascular disease. However, the role of OH in the development of atrial fibrillation has not been studied.
DESIGN: We investigated the incidence of atrial fibrillation in relation to baseline presence of OH according to international consensus criteria in the Swedish population-based prospective cohort of the Malmö Preventive Project. The study sample consisted of 33,346 individuals (67.3% men; mean age, 45.6 ± 7.4 years; range, 26-61 years). The association between OH and incidence of atrial fibrillation during follow-up was assessed using the Kaplan-Meier method and multivariable Cox proportional hazard models, taking into account conventional risk factors for atrial fibrillation.
RESULTS: At baseline, 1987 participants (6.1%) met the diagnostic criteria for OH. Over a follow-up period of approximately 24 years, 2312 individuals (3.0 events/1000 person-years) were diagnosed with new-onset atrial fibrillation. Of these, 196 had OH at baseline (4.6 events/1000 person-years amongst all OH-positive individuals). In a multivariable Cox regression analysis, OH predicted incidence of atrial fibrillation independently of other risk factors (hazard ratio [HR]: 1.30; 95% confidence interval [CI]: 1.05-1.61; P = 0.016), and this association was significant in hypertensive (HR: 1.44; 95%CI: 1.10-1.88; P = 0.008), but not in normotensive participants (HR: 1.10; 95%CI: 0.77-1.58; P = 0.60).
CONCLUSIONS: The presence of OH predicts the incidence of atrial fibrillation in middle-aged hypertensive individuals, independently of conventional risk factors. Further studies of the association of autonomic dysfunction and OH with atrial fibrillation are needed.