title: [The relationship of in-hospital and post-discharge complications and implications for quality measurement in hip replacement surgery - an analysis of AOK administrative data].
abstract: OBJECTIVE
  This study analyses the information gain achieved by additionally taking into account complications in the follow-up period instead of merely considering in-house events for a hospital-based quality measurement using the example of hip replacement.
  
  
  METHODS
  The analysis was performed with anonymous statutory health insurance data (AOK) for the years 2007-2009 within the framework of the quality measurement method "Quality Assurance with Administrative Data (QSR)". It included cases of hip replacement surgery due to osteoarthritis. In order to analyse hospital-related outcome quality, 6 quality indicators were formed (revision surgery within 365 days, surgical complications within 90 days, thrombosis/pulmonary embolism within 90 days, femur fracture within 90 days, mortality within 90 days and complication index). For each hospital, the adjusted SMRs (standardised mortality or morbidity ratio) with 95% confidence intervals were calculated. The relation between the in-hospital and the follow-up SMR was analysed by Spearman's rank correlation coefficient. Furthermore, the percentage consistency of hospital SMRs categorised into quartiles on the basis of in-hospital and post-discharge events was determined.
  
  
  RESULTS
  A total of 154 470 AOK patients from 930 hospitals were included in the analysis. The hospitals had a median overall complication rate of 11,22%. One quarter of the hospitals had complication rates of 8,18% or below. Another quarter of the hospitals had complication rates nearly twice as high (≥15,49%). Nearly one-third of all complications occurred after the initial hospitalisation. Regarding clinic-related complications, there was little correlation between the events in the initial case and during follow-up (r<0,3) for all indicators. The order of the hospitals defined by quartiles of SMR changed significantly by adding the complications in the follow-up for the indicators considered (min 21%, max 47% changes between quartiles). In particular, for the indicators revision and death, a change in the SMR quartile occurred in almost 50% of all hospitals.
  
  
  CONCLUSIONS
  Quality assessment of hip replacement surgery based exclusively on in-house events is quite unreliable. On the one hand, nearly a third of all complications occur in the follow-up period. On the other hand, predicting the occurrence of post-discharge events from in-house complications of a clinic is not considered acceptable for the indicators analysed in this study.
authors.affiliation: Wissenschaftliches Institut der AOK (WIdO), Berlin. elke.jeschke@wido.bv.aok.de
authors.forename: E
authors.initials: E
authors.lastname: Jeschke
authors.forename: K
authors.initials: K
authors.lastname: Heyde
authors.forename: C
authors.initials: C
authors.lastname: Günster
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip / Q000401:mortality*; D015897:Comorbidity; D005260:Female; D005858:Germany / Q000453:epidemiology; D017052:Hospital Mortality; D006760:Hospitalization / Q000706:statistics & numerical data*; D006801:Humans; D007593:Joint Instability / Q000401:mortality* / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D010351:Patient Discharge / Q000706:statistics & numerical data*; D011183:Postoperative Complications / Q000401:mortality*; D015995:Prevalence; D011785:Quality Assurance, Health Care / Q000379:methods / Q000706:statistics & numerical data*; D012307:Risk Factors; D016019:Survival Analysis; D015996:Survival Rate