title: Development of a predictive model to identify inpatients at risk of re-admission within 30 days of discharge (PARR-30).
abstract: OBJECTIVE
  To develop an algorithm for identifying inpatients at high risk of re-admission to a National Health Service (NHS) hospital in England within 30 days of discharge using information that can either be obtained from hospital information systems or from the patient and their notes.
  
  
  METHODS
  Multivariate statistical analysis of routinely collected hospital episode statistics (HES) data using logistic regression to build the predictive model. The model's performance was calculated using bootstrapping.
  
  
  METHODS
  HES data covering all NHS hospital admissions in England.
  
  
  METHODS
  The NHS patients were admitted to hospital between April 2008 and March 2009 (10% sample of all admissions, n=576 868).
  
  
  METHODS
  Area under the receiver operating characteristic curve for the algorithm, together with its positive predictive value and sensitivity for a range of risk score thresholds.
  
  
  RESULTS
  The algorithm produces a 'risk score' ranging (0-1) for each admitted patient, and the percentage of patients with a re-admission within 30 days and the mean re-admission costs of all patients are provided for 20 risk bands. At a risk score threshold of 0.5, the positive predictive value (ie, percentage of inpatients identified as high risk who were subsequently re-admitted within 30 days) was 59.2% (95% CI 58.0% to 60.5%); representing 5.4% (95% CI 5.2% to 5.6%) of all inpatients who would be re-admitted within 30 days (sensitivity). The area under the receiver operating characteristic curve was 0.70 (95% CI 0.69 to 0.70).
  
  
  CONCLUSIONS
  We have developed a method of identifying inpatients at high risk of unplanned re-admission to NHS hospitals within 30 days of discharge. Though the models had a low sensitivity, we show how to identify subgroups of patients that contain a high proportion of patients who will be re-admitted within 30 days. Additional work is necessary to validate the model in practice.
authors.affiliation: Robert F. Wagner Graduate School of Public Service, New York University, New York, USA.
authors.forename: John
authors.initials: J
authors.lastname: Billings
authors.forename: Ian
authors.initials: I
authors.lastname: Blunt
authors.forename: Adam
authors.initials: A
authors.lastname: Steventon
authors.forename: Theo
authors.initials: T
authors.lastname: Georghiou
authors.forename: Geraint
authors.initials: G
authors.lastname: Lewis
authors.forename: Martin
authors.initials: M
authors.lastname: Bardsley