Research article
Is there a clinically significant seasonal component to hospital admissions for atrial fibrillation?
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* Corresponding author: Ross EG Upshur rupshur@idirect.com
1 Primary Care Research Unit, Sunnybrook and Women's College Health Sciences Centre, 2075 Bayview Avenue, #E-349, Toronto, Ontario, Canada M4N 3M5
2 Departments of Family and Community Medicine, University of Toronto, 256 McCaul, Street, 2nd Floor, Toronto, Ontario, Canada M5T 2W5
3 Department of Public Health Sciences, University of Toronto, McMurrich Building, 12, Queen's Park Crescent W., Toronto, Ontario, Canada M5S 1A8
4 Institute of Clinical Evaluative Sciences (ICES), 2075 Bayview Avenue, Toronto, Ontario, Canada M4N 3M5
5 Health Policy Management and Evaluation, University of Toronto, McMurrich Building, 2nd Floor, 12 Queen's Park Crescent W., Toronto, Ontario, Canada M5S 1A8
6 Faculty of Pharmacy, University of Toronto, 19 Russell Street, Toronto, Ontario, Canada, M5S 2S2
BMC Health Services Research 2004, 4:5 doi:10.1186/1472-6963-4-5
Published: 19 March 2004Abstract
Background
Atrial fibrillation is a common cardiac dysrhythmia, particularly in the elderly. Recent studies have indicated a statistically significant seasonal component to atrial fibrillation hospitalizations.
Methods
We conducted a retrospective population cohort study using time series analysis to evaluate seasonal patterns of atrial fibrillation hospitalizations for the province of Ontario for the years 1988 to 2001. Five different series methods were used to analyze the data, including spectral analysis, X11, R-Squared, autocorrelation function and monthly aggregation.
Results
This study found evidence of weak seasonality, most apparent at aggregate levels including both ages and sexes. There was dramatic increase in hospitalizations for atrial fibrillation over the years studied and an age dependent increase in rates per 100,000. Overall, the magnitude of seasonal difference between peak and trough months is in the order of 1.4 admissions per 100,000 population. The peaks for hospitalizations were predominantly in April, and the troughs in August.
Conclusions
Our study confirms statistical evidence of seasonality for atrial fibrillation hospitalizations. This effect is small in absolute terms and likely not significant for policy or etiological research purposes.