title: Factors affecting in-hospital heat-related mortality: a multi-city case-crossover analysis.
abstract: BACKGROUND
  Several studies have identified strong effects of high temperatures on mortality at population level; however, individual vulnerability factors associated with heat-related in-hospital mortality are largely unknown. The objective of the study was to evaluate heat-related in-hospital mortality using a multi-city case-crossover analysis.
  
  
  METHODS
  We studied residents of four Italian cities, aged 65+ years, who died during 1997-2004. For 94,944 individuals who died in hospital and were hospitalised two or more days before death, demographics, chronic conditions, primary diagnoses of last event and hospital wards were considered. A city-specific case-crossover analysis was performed to evaluate the association between apparent temperature and mortality. Pooled odds ratios (OR) of dying on a day with a temperature of 30 degrees C compared to a day with a temperature of 20 degrees C were estimated with a random-effects meta-analysis.
  
  
  RESULTS
  We estimated an overall OR of 1.32 (95% confidence interval: 1.25, 1.39). Age, marital status and hospital ward were important risk indicators. Patients in general medicine were at higher risk than those in high and intensive care units. A history of psychiatric disorders and cerebrovascular diseases gave a higher vulnerability. Mortality was greater among patients hospitalised for heart failure, stroke and chronic pulmonary diseases.
  
  
  CONCLUSIONS
  In-hospital mortality is strongly associated with high temperatures. A comfortable temperature in hospitals and increased attention to vulnerable patients during heatwaves, especially in general medicine, are necessary preventive measures.
authors.affiliation: Department of Epidemiology, Rome E Health Authority, Rome, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Stafoggia
authors.forename: F
authors.initials: F
authors.lastname: Forastiere
authors.forename: D
authors.initials: D
authors.lastname: Agostini
authors.forename: N
authors.initials: N
authors.lastname: Caranci
authors.forename: F
authors.initials: F
authors.lastname: de'Donato
authors.forename: M
authors.initials: M
authors.lastname: Demaria
authors.forename: P
authors.initials: P
authors.lastname: Michelozzi
authors.forename: R
authors.initials: R
authors.lastname: Miglio
authors.forename: M
authors.initials: M
authors.lastname: Rognoni
authors.forename: A
authors.initials: A
authors.lastname: Russo
authors.forename: C A
authors.initials: CA
authors.lastname: Perucci
mesh_terms: D000368:Aged; D004812:Epidemiologic Methods; D005260:Female; D017052:Hospital Mortality; D006760:Hospitalization; D006358:Hot Temperature / Q000009:adverse effects*; D006801:Humans; D007558:Italy / Q000453:epidemiology; D008297:Male; D013696:Temperature; D014504:Urban Health / Q000706:statistics & numerical data*