Abstract 16759: Seasonal Variations in Cardiovascular-related Mortality But Not Hospitalization Are Modulated by Temperature and Not Climate Type: a Systematic Review and Meta-analysis of 4.5 Million Events in 26 Countries
Introduction: We undertook a systematic review and meta-analysis of seasonal variations in cardiovascular-related events across a range of climatic conditions.
Methods: A systematic review of bibliographic databases (inception to December 31 2015) was performed according to PRISMA guidelines. Eligible articles (48/163 fully assessed) reported the effect of seasonality on CVD mortality or hospitalization for a full calendar year at a region/population level. Study regions were coded by Köppen-Geiger Climate Classification and by summer and winter mean temperature. Meta-analyses on counts of events occurring in the month/season of peak versus trough activity were performed on large-scale, regional studies (n=24) with ≥10,000 events. Sub-group analyses of climatic variations, CVD subtypes and participant demographics were performed.
Results: Forty-eight studies from 26 countries (17 European) comprised 2.9 and 1.6 million CVD hospitalizations and deaths, respectively. The majority emanated from Moist Mid-latitude (Mild) Climates (n=31) with a range of sub-climate categories represented. All but three studies reported seasonal patterns in CVD events with a predominant pattern of winter peaks (n=40). Meta-analysis revealed more CVD-related deaths [IRR 1.23, 95% CI 1.16-1.31; n=12] and hospitalizations [IRR 1.20, 95% CI 1.14-1.25; n=19] during peak versus trough season (p<0.0001). Seasonal variation in CVD mortality (but not morbidity), was greater [IRR 1.21, 95% CI 1.15-1.27] in studies with a mean absolute temperature difference <17°C versus ≥17°C (p<0.0001). Seasonal variations were also greater in women [IRR 1.07 95% CI 1·03-1·11] and in older adults [IRR 1.04 95% CI 1.00-1.08], p<0.001 for both.
Conclusions: Seasonal variation, largely winter peaks, in CVD events occurs in a range of climates across the globe. Paradoxically, in milder climates seasonal mortality may be worse. This has clinical implications for public health measures in this vulnerable population, particularly elderly women.
Author Disclosures: S. Stewart: None. Y. Ahamed: None. J.F. Wiley: None. C.J. McDermott: None. J. Ball: None. A.K. Keates: None. M. Løchen: None. M.J. Carrington: None.
- © 2016 by American Heart Association, Inc.