title: A study of the short-term associations between hospital admissions and mortality from heart failure and meteorological variables in Hong Kong: Weather and heart failure in Hong Kong.
abstract: BACKGROUND
  Previous research has shown winter peaks for both hospitalizations and mortality from HF, but few studies have examined the association between meteorological parameters and HF.
  
  
  METHODS
  Daily HF admissions to Hong Kong public hospitals, which cover about 83% of total admissions, and daily HF deaths, were obtained for 2002-2011. Generalized additive (Poisson) regression models were used with daily HF admissions/mortality as outcomes and daily mean temperature, humidity, and wind speed as predictors, while controlling for pollutant levels, time trend, season, day of the week, and holiday. Non-linear distributed lag functions were used for predictors to allow for non-linear and delayed associations.
  
  
  RESULTS
  Lower mean daily temperatures were strongly associated with increased HF admissions and mortality with a cumulative (to 23days) relative risk (RR) (95% confidence interval (CI)) for HF admissions of 2.63 (2.43, 2.84) for an 11°C. vs. a 25°Cday, and cumulative (42days) RR (95% CI)=3.13 (1.90, 5.16) for HF mortality. The association with cold weather was stronger among older age groups and for new hospitalizations compared to recurrent ones, while presence of co-morbidities did not modify the association. Both high and low relative humidity were modestly associated with more admissions.
  
  
  CONCLUSIONS
  Both HF admissions and mortality in Hong Kong were very strongly associated with cold temperatures. Reducing exposure to cold temperatures among those at risk for HF has the potential to reduce hospitalizations and mortality.
authors.affiliation: Division of Biostatistics, School of Public Health and Primary Care, The Chinese University of Hong Kong, Shatin, Hong Kong. Electronic address: wgoggins@cuhk.edu.hk.
authors.forename: William B
authors.initials: WB
authors.lastname: Goggins
authors.affiliation: Division of Family Medicine, School of Public Health and Primary Care, The Chinese University of Hong Kong, Shatin, Hong Kong.
authors.forename: Emily Yy
authors.initials: EY
authors.lastname: Chan
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D004781:Environmental Exposure / Q000009:adverse effects*; D005260:Female; D005500:Follow-Up Studies; D006333:Heart Failure / Q000401:mortality* / Q000628:therapy; D006723:Hong Kong / Q000453:epidemiology; D017052:Hospital Mortality / Q000639:trends; D006779:Hospitals, Public / Q000706:statistics & numerical data*; D006801:Humans; D008297:Male; D010343:Patient Admission / Q000706:statistics & numerical data*; D012189:Retrospective Studies; D018570:Risk Assessment / Q000379:methods*; D012307:Risk Factors; D013997:Time Factors; D014887:Weather
keywords: Environment; Heart failure; Modeling; Morbidity/mortality; Weather