title: Diagnosis of acute kidney injury and its association with in-hospital mortality in patients with infective exacerbations of bronchiectasis: cohort study from a UK nationwide database.
abstract: BACKGROUND
  Many patients with bronchiectasis have recurrent hospitalisations for infective exacerbations. Acute kidney injury (AKI) is known to be associated with increased in-hospital mortality. This study examined the frequency of AKI, associated risk-factors, and the association of AKI with in-hospital mortality among patients with bronchiectasis.
  
  
  METHODS
  Anonymised data of patients with non-cystic fibrosis bronchiectasis from the UK Clinical Practice Research Datalink, linked to Hospital Episode Statistics, were used to identify hospitalisations with a primary diagnosis of lower respiratory tract infection (LRTI), from 2004 to 2013. After estimating the proportion of AKI diagnoses, a multivariable logistic regression model was constructed to investigate which background factors were associated with AKI. In-hospital mortality was compared between hospitalisations with and without an AKI diagnosis, with subsequent logistic regression analyses carried out for the association between AKI and in-hospital mortality.
  
  
  RESULTS
  Of 7804 hospitalisations due to LRTI observed in 3477 patients with bronchiectasis, 230 hospitalisations involved an AKI diagnosis, an average of 2.9%. However, the percentage increased from less than 2% in 2004 to nearly 5% in 2013. After taking this temporal change into account, AKI was independently associated with older age, male sex, decreased baseline kidney function, previous history of AKI, and a diagnosis of sepsis. In-hospital mortality was 33.0% (76/230) and 6.8% (516/7574), in hospitalisations with and without AKI, respectively (P < 0.001). After adjustment for confounding factors, diagnosis of AKI remained associated with in-hospital mortality (Odds ratio 5.52, 95% confidence interval: 3.62-8.42).
  
  
  CONCLUSIONS
  Among people with bronchiectasis hospitalised for infective exacerbations, there is an important subgroup of patients who develop AKI. These patients have substantially increased in-hospital mortality and therefore greater awareness is needed.
authors.affiliation: Department of Non-Communicable Disease Epidemiology, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK. masao.iwagami@lshtm.ac.uk.
authors.forename: Masao
authors.initials: M
authors.lastname: Iwagami
authors.affiliation: Department of Non-Communicable Disease Epidemiology, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK. Kathryn.Mansfield@lshtm.ac.uk.
authors.forename: Kathryn
authors.initials: K
authors.lastname: Mansfield
authors.affiliation: Department of Non-Communicable Disease Epidemiology, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK. j.quint@imperial.ac.uk.|Department of Respiratory Epidemiology, Occupational Medicine and Public Health, National Heart and Lung Institute, Imperial College London, London, UK. j.quint@imperial.ac.uk.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Quint
authors.affiliation: Department of Non-Communicable Disease Epidemiology, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK. Dorothea.Nitsch@lshtm.ac.uk.
authors.forename: Dorothea
authors.initials: D
authors.lastname: Nitsch
authors.affiliation: Department of Non-Communicable Disease Epidemiology, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK. laurie.tomlinson@lshtm.ac.uk.
authors.forename: Laurie
authors.initials: L
authors.lastname: Tomlinson
mesh_terms: D058186:Acute Kidney Injury / Q000453:epidemiology*; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D057911:Angiotensin Receptor Antagonists / Q000627:therapeutic use; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000627:therapeutic use; D001987:Bronchiectasis / Q000453:epidemiology*; D015331:Cohort Studies; D016208:Databases, Factual; D003920:Diabetes Mellitus / Q000453:epidemiology; D018450:Disease Progression; D004232:Diuretics / Q000627:therapeutic use; D005260:Female; D005919:Glomerular Filtration Rate; D006333:Heart Failure / Q000453:epidemiology; D017052:Hospital Mortality; D006760:Hospitalization; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D011014:Pneumonia / Q000453:epidemiology*; D051436:Renal Insufficiency, Chronic / Q000453:epidemiology*; D012307:Risk Factors; D018805:Sepsis / Q000453:epidemiology*; D012737:Sex Factors; D006113:United Kingdom / Q000453:epidemiology
chemical_list: D057911:Angiotensin Receptor Antagonists; D000806:Angiotensin-Converting Enzyme Inhibitors; D004232:Diuretics