European Heart Journal Advance Access originally published online on August 1, 2007
European Heart Journal 2007 28(19):2346-2353; doi:10.1093/eurheartj/ehm308
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Increased mortality in paroxysmal atrial fibrillation: report from the Stockholm Cohort-Study of Atrial Fibrillation (SCAF)
1 Department of Clinical Science and Education, Karolinska Institute at South Hospital, Stockholm, Sweden
2 Institute of Enviromental Medicine, Karolinska Institute, Stockholm, Sweden
3 AstraZeneca R&D, Mölndal, Sweden
4 Department of Clinical Science and Education, Section of Statistics, Karolinska Institute South Hospital, Stockholm, Sweden
5 Department of Cardiology and Department of Clinical Science and Education, Karolinska Institute South Hospital, Stockholm, Sweden
Received 9 March 2007; revised 28 May 2007; accepted 21 June 2007; online publish-ahead-of-print 1 August 2007.
* Corresponding author: Globen Heart Clinic, Karolinska Institute, Storskogsvägen 5, S-167 65 Bromma, Sweden. Tel: +46 8 648 23 53; fax: +46 8 556 138 50. E-mail address: leif.friberg{at}stockholm.bonet.se
Aims: Whether paroxysmal atrial fibrillation (PxAF) affects survival is poorly recognized. Results have been conflicting in the few previously published studies. To describe mortality in patients with PxAF and to identify risk factors amenable to treatment.
Methods and results: All patients (n = 2824) treated for atrial fibrillation during 2002 at one of Scandinavia's largest hospitals were followed prospectively for a mean of 4.6 years. Information about type of AF, comorbidity, and medication was acquired from medical records and national registers. Information about deaths was obtained from the National Cause of Death Register. One-third (n = 888) of the patients had PxAF (mean age 73 years). During follow-up, 267 of them died. The mean annual mortality rate was 7%. Compared with the general population, the standardized mortality ratio (SMR) was 1.6 (95% CI 1.4–1.8) for all-cause mortality, 2.4 (95% CI 1.4–3.7) for death from myocardial infarction, and 2.6 (95% CI 1.3–5.2) for death from heart failure. Warfarin treatment was associated with improved survival both in comparison with the general population (SMR 1.1 with warfarin, SMR 2.2 without warfarin) and after propensity score matching for odds to receive warfarin (HR 0.5, 95% CI 0.3–0.9). The improvement of survival could not be explained by stroke reduction alone.
Conclusion: PxAF is associated with increased mortality, which mostly appears to be related to concomitant cardiovascular risks. Treatment with warfarin is associated with improved survival in PxAF patients.
Key Words: Paroxysmal atrial fibrillation • Cohort study • Mortality • Risk factor • Anticoagulation