title: Obstructive sleep apnea among hospitalized patients in Spain, analysis of hospital discharge data 2008-2012.
abstract: BACKGROUND
  The aim of this study is to describe clinical characteristics, diagnostic and therapeutic procedure (polysomnography and continuous positive airway pressure (CPAP)/bi-level positive airway pressure (BPAP)), comorbidity, length of hospital stay (LOHS), discharge destination, and in-hospital mortality (IHM) of patients hospitalized for obstructive sleep apnea (OSA) in Spain over a 5-year study period.
  
  
  METHODS
  We included all patients who were hospitalized for OSA (ICD9-CM code 327.23) as primary or secondary diagnosis between 2008 and 2012. Data were collected from the National Hospital Discharge Database, covering the entire Spanish population.
  
  
  RESULTS
  We identified 196,769 discharges of patients admitted for OSA. The number of patients with OSA as primary or secondary diagnosis increased from 2008 to 2012 from 5358 to 7992 and 14,916 to 51,135 respectively. The mean age was 50.7 ± 20.3 years in patients admitted for OSA as primary diagnosis (n = 32,010) and 63.7 ± 17.6 years in patients admitted for OSA as secondary diagnosis (n = 164,759). The most common secondary diagnoses for patients discharged with a primary diagnosis of OSA was arterial hypertension (19.0%), obesity (16.9%), disorders of lipid metabolism (8.01%) and diabetes mellitus (6.48%). The most common primary diagnoses for patients discharged with a secondary diagnosis of OSA were obesity (12.5%), heart failure (9.6%), and chronic bronchitis (4.5%). The percentage of patients that received continuous positive airway pressure (CPAP)/bi-level positive airway pressure (BPAP) therapy was 11.3%. Patients who received this therapy had a higher length of stay compared with those who did not (10.4 ± 14.1 versus 7.3 ± 9.5 days, respectively, p < 0.05) and were less likely to be discharged to home (87.2 versus 91.1%, p < 0.05). The mortality was higher in the first group of patients (9 versus 5.6%, p < 0.05). Multivariate analysis showed that each year from 2008 to 2012, the mean probability of having OSA as primary diagnosis increased an average of 8%, and 33% as secondary diagnosis, after adjusting for other variables.
  
  
  CONCLUSIONS
  The results of this study reveal a national perspective on the characteristics and management of OSA in hospitalized patients in Spain during the period of 2008-2012. The burden of the disease seems to be increasing in Spain. Clinical studies are needed to provide a better knowledge of OSA in this subgroup of patients.
authors.affiliation: Pneumology Department, Hospital General Universitario Gregorio Marañon, C/ Doctor Esquerdo 46, 28007, Madrid, Spain, javier.miguel@salud.madrid.org.
authors.forename: Javier
authors.initials: J
authors.lastname: de Miguel-Díez
authors.forename: Pilar
authors.initials: P
authors.lastname: Carrasco-Garrido
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Jiménez-García
authors.forename: Luis
authors.initials: L
authors.lastname: Puente-Maestu
authors.forename: Valentín
authors.initials: V
authors.lastname: Hernández-Barrera
authors.forename: Ana
authors.initials: A
authors.lastname: López de Andrés
mesh_terms: D000328:Adult; D000368:Aged; D015897:Comorbidity; D045422:Continuous Positive Airway Pressure; D003430:Cross-Sectional Studies; D005260:Female; D017052:Hospital Mortality; D006760:Hospitalization; D006801:Humans; D007902:Length of Stay / Q000706:statistics & numerical data; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D010351:Patient Discharge; D017286:Polysomnography; D020181:Sleep Apnea, Obstructive / Q000175:diagnosis* / Q000453:epidemiology* / Q000401:mortality / Q000628:therapy; D013030:Spain