title: Burn injury during long-term oxygen therapy in Denmark and Sweden: the potential role of smoking.
abstract: BACKGROUND
  Long-term oxygen therapy (LTOT) increases life expectancy in patients with COPD and severe hypoxemia. Smoking is the main cause of burn injury during LTOT. Policy regarding smoking while on LTOT varies between countries. In this study, we compare the incidence of burn injury that required contact with a health care specialist, between Sweden (a country with a strict policy regarding smoking while on LTOT) and Denmark (a country with less strict smoking policy).
  
  
  METHODS
  This was a population-based, cohort study of patients initiating LTOT due to any cause in Sweden and Denmark. Data on diagnoses, external causes, and procedures were obtained from the Swedish and Danish National Patient Registers for inpatient and outpatient care. Patients were followed from January 1, 2000, until the first of the following: LTOT withdrawal, death, or study end (December 31, 2009). The primary end point was burn injury during LTOT.
  
  
  RESULTS
  A total of 23,741 patients received LTOT in Denmark and 7,754 patients in Sweden. Most patients started LTOT due to COPD, both in Sweden (74%) and in Denmark (62%). The rate of burn injury while on LTOT was higher in Denmark than in Sweden; 170 (95% confidence interval [CI], 126-225) vs 85 (95% CI, 44-148) per 100,000 person-years; rate ratio 2.0 (95% CI, 1.0-4.1). The risk remained higher after adjustment for gender, age, and diagnosis in multivariate Cox regression, hazard ratio 1.8 (95% CI, 1.0-3.5). Thirty-day mortality after burn injury was 8% in both countries.
  
  
  CONCLUSIONS
  Compared to Sweden, the rate of burn injury was twice as high in Denmark where smoking is not a contraindication for prescribing LTOT.
authors.affiliation: Department of Respiratory Medicine, Skåne University Hospital, Lund University, Lund, Sweden.
authors.forename: Hanan A
authors.initials: HA
authors.lastname: Tanash
authors.affiliation: Respiratory Department, Hvidovre Hospital, Copenhagen, Denmark.
authors.forename: Thomas
authors.initials: T
authors.lastname: Ringbaek
authors.affiliation: Department of Surgical Sciences, Plastic Surgery; Department of Plastic and Maxillofacial Surgery, Burn Center, Uppsala University Hospital, Uppsala, Sweden.
authors.forename: Fredrik
authors.initials: F
authors.lastname: Huss
authors.affiliation: Department of Respiratory Medicine, Skåne University Hospital, Lund University, Lund, Sweden.
authors.forename: Magnus
authors.initials: M
authors.lastname: Ekström
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002056:Burns / Q000175:diagnosis / Q000453:epidemiology* / Q000401:mortality; D000075202:Contraindications; D003718:Denmark / Q000453:epidemiology; D005260:Female; D006801:Humans; D000860:Hypoxia / Q000175:diagnosis / Q000401:mortality / Q000503:physiopathology / Q000628:therapy*; D015994:Incidence; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D010102:Oxygen Inhalation Therapy / Q000009:adverse effects* / Q000401:mortality; D016016:Proportional Hazards Models; D011446:Prospective Studies; D029424:Pulmonary Disease, Chronic Obstructive / Q000175:diagnosis / Q000401:mortality / Q000503:physiopathology / Q000628:therapy*; D012042:Registries; D018570:Risk Assessment; D012307:Risk Factors; D012720:Severity of Illness Index; D012907:Smoking / Q000009:adverse effects* / Q000453:epidemiology* / Q000401:mortality; D013548:Sweden / Q000453:epidemiology; D055815:Young Adult
keywords: COPD; burn injury; long-term oxygen therapy; smoking