title: Increased registration of hypertension and cancer diagnoses after the introduction of a new reimbursement system.
abstract: OBJECTIVE
  To investigate the impact on ICD coding behaviour of a new case-mix reimbursement system based on coded patient diagnoses. The main hypothesis was that after the introduction of the new system the coding of chronic diseases like hypertension and cancer would increase and the variance in propensity for coding would decrease on both physician and health care centre (HCC) levels.
  
  
  METHODS
  Cross-sectional multilevel logistic regression analyses were performed in periods covering the time before and after the introduction of the new reimbursement system.
  
  
  METHODS
  Skaraborg primary care, Sweden.
  
  
  METHODS
  All patients (n = 76 546 to 79 826) 50 years of age and older visiting 468 to 627 physicians at the 22 public HCCs in five consecutive time periods of one year each.
  
  
  METHODS
  Registered codes for hypertension and cancer diseases in Skaraborg primary care database (SPCD).
  
  
  RESULTS
  After the introduction of the new reimbursement system the adjusted prevalence of hypertension and cancer in SPCD increased from 17.4% to 32.2% and from 0.79% to 2.32%, respectively, probably partly due to an increased diagnosis coding of indirect patient contacts. The total variance in the propensity for coding declined simultaneously at the physician level for both diagnosis groups.
  
  
  CONCLUSIONS
  Changes in the healthcare reimbursement system may directly influence the contents of a research database that retrieves data from clinical practice. This should be taken into account when using such a database for research purposes, and the data should be validated for each diagnosis.
authors.affiliation: R&D Centre, Skaraborg Primary Care, Skövde, Sweden. per.hjerpe@vgregion.se
authors.forename: Per
authors.initials: P
authors.lastname: Hjerpe
authors.forename: Kristina Bengtsson
authors.initials: KB
authors.lastname: Boström
authors.forename: Ulf
authors.initials: U
authors.lastname: Lindblad
authors.forename: Juan
authors.initials: J
authors.lastname: Merlo
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003430:Cross-Sectional Studies; D057286:Electronic Health Records / Q000706:statistics & numerical data; D018588:Fee-for-Service Plans; D005260:Female; D058006:General Practice / Q000458:organization & administration; D006801:Humans; D006973:Hypertension / Q000175:diagnosis*; D038801:International Classification of Diseases / Q000639:trends*; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009042:Motivation; D055361:Multilevel Analysis; D009369:Neoplasms / Q000175:diagnosis*; D011320:Primary Health Care; D013548:Sweden