Analysis of outpatient coding quality in german disease management programs

Background: The German health care reform act, which came in force 2011, canceled the outpatient coding reference. Firstly, the outpatient coding reference should have been the basis for the German risk structure compensation scheme, which was started in 2009. The aim of this study was to evaluate coding quality in Disease Management Programs (DMP). Methods: This study analyzed 350 million diagnoses of 2.7 million AOK PLUS insurants and 11k practitioners' in Saxony and Thuringia (Germany) from 2007 to 2010. We focused on the hypothesis that an insurant, which was registered in a DMP, had to get specific program diagnosis. For indication diagnoses were chosen ICD-10-GM I20 to I25 for CHD, J45 and J46 for asthma, J44 for COPD and E11 to E14 for diabetes mellitus. Results: During the years 2007 to 2009 we identified a lack of diagnoses for the insurants inside a DMP. In 2010 the number of falsely coded insurants decreased from 9,206 to 1,839. According to the DMP the analysis suggest that diabetes mellitus patients were the best coded group with the least error ratio (2007: 0.31%, 2008: 0.24%, 2009: 0.16%, 2010: 0.06%). The worst outpatient coding quality was caused in the DMP CHD (2007: 9.42%, 2008: 10.12%, 2009: 9.22%, 2010: 1.33%). Conclusion: Study findings suggest that the outpatient coding quality escalated in 2010. The AOK PLUS advised 2010 general practitioners to the coding quality according to the DMP insurants. So, the changes can be explained because of this intervention and not to an independent attitude change.