DRG systems around the world and financing methods
Each week during the summer, summaries of chapters from the book Diagnosis Related Groups in Europe, available HERE, will be presented.
The DRG system, as one of the most represented types of patient classification systems (PCSs) in Europe, is defined as a system providing for the classification of a large number of clinically unique patients, based on data collected from the period of their hospitalisation, into a limited number of so-called DiagnosticRelatedGroups (DRGs) that are clinically relevant and economically homogeneous.
DRG systems are mainly used in European countries as mechanisms for objective financing of health care facilities. The payment mechanism of DRG systems starts with the classification of patients, which takes place automatically through software that uses a classification algorithm to assign hospital cases (patients) to DRG groups. For correct grouping, the algorithm needs to take into account variables that significantly affect the financial burden that the patient represents for the healthcare facility, which includes information about the patient, the nature of the treatment or the healthcare provider. Thus, each final DRG contains a group of cost and clinical similar cases and its burden in relation to resource consumption is weighted by a DRG weighting factor. In the context of the correct setting of the DRG weight of a specific DRG, the quality of the data obtained from hospitals is important, as it is crucial for assessing the correctness of reimbursement and is the basis for the recalculation of DRG weights. This is further linked to the fact that DRG systems need to be regularly developed and updated, for example by creating new groups and recalculating DRG weights so that the introduction of new technologies and treatments in hospitals is adequately reflected in the DRG system. Hence the trend towards a gradual increase in the number of final DRGs in the systems of European countries, with the possible exception of the Dutch DBC system with the opposite tendency due to the initially high number of groups (100 000 in 2005, 30 000 in 2010, the target is to drop to 3 000).
As already mentioned, DRG systems are among the most widely used patient classification systems (PCSs) in Europe. They can be broadly divided into the following 2 types of DRG-systems
Although the general structure of the European DRG systems is quite similar, each of the systems, whether adopted or newly developed, is adapted to the needs of the health system of the country concerned, they therefore differ from each other to varying degrees and a brief comparison of them is given in the following lines.
COMPARISON OF DRG AND DRG-LIKE SYSTEMS IN SELECTED EUROPEAN COUNTRIES
The first of the differences between countries that can be observed is the number of defined DRGs, which varies between 650 and 2300. Exceptions are Poland with 518 groups and the Dutch DBC system with a total of up to 30 000 DBC groups (valid for the 2010 version).
Significant heterogeneity when comparing European systems is shown in the coding of diagnoses and health interventions (HI). The coding of diagnoses is based on the international standard, which is the WHO's International Classification of Diseases (ICD), but in almost every country it is possible to encounter country-specific adaptations in coding, which result from country-specific needs. However, much more significant differences are seen in the coding of ZV, due to the lack of an international standard. The coding therefore varies not only in format but also in the number of coded WGs, resulting in the fact that there are differences of tens of times in the number of coded WGs between some countries.
STRUCTURE OF DRG-SYSTEMS AND BASIC COMPARISON OF CLASSIFICATION ALGORITHMS OF PCS SYSTEMS OF SELECTED EUROPEAN COUNTRIES
In HCFA-DRG-derived systems, DRG groups are organized under MDC (Main Diagnostic Category), which in DRG systems are usually around 25 in number, as they are categories created by organ systems or disease entities. The MDCs are further subdivided into 2-3 segments - Operational, Medical, Non-operational/Other, which are further subdivided into Core DRGs, and then Final DRGs. The structure of DRG-like systems is similar, but in some systems, such as the English and Polish systems, the equivalent MDCs are so-called chapters, and in addition to the final DRGs, additional groups are defined into which cases are classified in the first stages of classification, for example, when specific medical procedures are performed or when treatment is provided in a specific hospital department.
The algorithm for classifying inpatient cases in systems derived from HCFA-DRG PCSs generally consists of six steps that lead to the classification of inpatient cases into a final DRG group. The process begins with a primary review of the attributed case data to ensure that (1) cases with incorrect or missing information are excluded from further classification. In the next step, (2) high-cost cases are selected and classified into special so-called Pre-MDC groups. Cases are then classified on the basis of principal diagnosis(HDg), in some cases also on the basis of age, into (3) MDCs, within which they are subsequently assigned to (4) a specific segment(surgical, medical, non-operative/other). An important step in the triage process is (5) narrower case characterization taking into account the complexity of the case, co-diagnoses, type of medical procedures performed and their combination, age or hospitalization time and treatment setting, which ultimately leads to the assignment of cases to a single class (AP-DRG; All-Patient-DRG) or base DRG group (other systems) that best reflects the financial costliness of a particular hospitalization case. In the last step of the classification algorithm, after taking into account co-morbid diagnoses, performed EPs, age, discharge method or major complications and comorbidities (6), the case is assigned to a final DRG group that further specifies the differences in cost-effectiveness of cases falling into the base DRG group/class, which may be identical to the base DRG group/class if all cases falling into the base DRG group are cost homogeneous.
In contrast to HCFA-derived DRG systems, the main role in the classification process in the newly developed DRG-like PCS systems - HRG, JGP and LFK systems - is played by the medical procedures provided, which are weighted in the classification process according to the set criteria of each country, but the classification process itself is quite similar.
A completely different system among the newly developed PCSs is the Dutch DBC with an incomparably high number of finite groups, which classifies cases into groups by sequentially considering specific parameters within four to five dimensions.
Placement in the final DRG group is the result of taking into account the many variables affecting the amount of money spent by the hospital to treat the patient during the hospitalisation.
The principal diagnosis and the ZVs provided have a significant impact on DRG inclusion. The term 'principal diagnosis' may be understood differently in different systems, either as the diagnosis that is the reason for hospitalisation or as the diagnosis that is the highest in the system-defined hierarchy.
Other important parameters are the length of hospital stay and the method of discharge, or demographic data, perhaps the most important of which is the age of the patient. An exception is the NordicDRG system, in which, compared to other systems, gender is also a very important factor for inclusion.
In all systems except DBC and LKF, secondary diagnoses largely influence the inclusion of a case in the final DRG. However, the difference lies in the way the different systems deal with multiple secondary diagnoses - for example, while in G-DRG the cumulative effect of all secondary diagnoses, the so-called PCCL (Patient Clinical Complexity Level), is applied, in most other DRG systems the costliness is determined only by the secondary diagnosis with the highest severity. A different approach is taken in the GHM system, where the cumulative effect is the result of simultaneously taking into account the most severe secondary diagnosis together with age, length of hospital stay and possible death during hospitalisation. The Dutch DBC system does not take the secondary diagnoses into account for grouping, instead the patient with the treated secondary diagnosis is assigned to the appropriate new DBC group.
The vision of a common European DRG system may seem impossible at first sight, given the above comparison of DRG and DRG-like systems, as the comparison only confirms the great diversity across systems. However, viewed from the opposite angle, the differences identified can serve as an indicator of the areas within the systems that need to be addressed first in the sense of striving for a common and unified system. The huge advantage is that many of the already 'established' systems with elements that have been proven in practice can serve as a basis for the creation of a common Euro-DRG system. Its creation is therefore a vision for the distant future, but it is not an unachievable goal with a great deal of effort and considerable political support.