Australian National Diagnosis Related Groups Research Articles

PMS8 - Hospital Admissions and Inpatient Costs of Non-Union, Delayed Union and Mal-Union Following Long Bone Fracture

Previous research into healing complications following long bone fractures has reported a wide range of cost estimates associated with their treatment. This research aims to describe hospital admissions and inpatient costs of hospital readmissions for healing complications following long bone fracture. All femoral, tibial and humeral fractures registered over a 5-year period by the Victorian Orthopaedic Trauma Outcomes Registry were linked with hospital datasets to identify 2-year readmissions for non-union, delayed union or mal-union. Outcomes reported included hospital admissions, length of stay and inpatient costs, derived using a case-mix approach based on Australian National Diagnosis Related Groups (AN-DRG). Out of 3908 patients with long bone fractures, 9% (n=337) were readmitted for healing complications within 2 years of their fracture. The most common type of complication resulting in readmission was non-union (7%). The majority of patients experiencing fracture healing complications were admitted once within two years of their index fracture. However, 12% had 2 admissions for healing complications during this period, 2% had three admissions and 1% (n=2) had four. The total inpatient costs for all admissions for fracture healing complications in this cohort was $5.4MAUD. The median inpatient hospital cost per patient for all complication admissions was $15,000AUD over and above the baseline fracture treatment costs and ranged from $9,500 to $25,000. The median hospital length of stay for all complication admissions was 3 days. Patients who develop fracture healing complications often have multiple admissions for treatment and incur high hospital inpatient costs. There is a need to prioritise future research aimed at preventing fracture healing complications and improving their management in order to reduce the additional burden placed on healthcare systems.

Critical care dependency tool: Monitoring the changes

The critical care patient dependency system (CCPD) is a factorial patient acuity system developed in 1993 by Ferguson and Harris-Ingall 1 for use in adult critical care areas. It was developed specifically to help determine Australian nursing cost weights and was utilised to collect data from nine Sydney critical care units from October 1992 until May 1993. The St. George Hospital (SGH) general intensive care unit, one of the nine participating hospitals, continues to use and collect data with the CCPD. This paper describes the instrument and compares data on Australian national diagnosis related groups (ANDRGs), collected during the original study, to ANDRG information on the critical care population 3 and 6 years later. In addition, the paper examines and compares the demographics of the SGH critical care patient population, patient acuity (based upon CCPD patient scores) and intensive care nursing clinical practices collected over a 3 month period in 1996 and again in 1999. Demographic and patient acuity data for SGH in 1993 are unavailable and so comparisons were unable to be made. The findings demonstrate changes in the management of critically ill patients, especially in relation to ventilation management, wound care and invasive monitoring practices; this resulted in shifts to the nursing workload. For this reason, the instrument is useful in providing nurse managers with information about patient dependencies and nursing work.

The effectiveness of AN-DRGs in classification of acute admitted patients with diabetes.

The Australian National Diagnosis Related Groups (AN-DRGs) classification is intended to assign acute admitted patient episodes to classes which are iso-resource and clinically homogeneous. It has been widely used to good effect, but its performance has been questioned with respect to the classification of patients with chronic conditions. The primary aim of this study was to investigate the extent to which AN-DRGs classify episodes of care for a chronic disorder (in this case diabetes) into classes which are relatively homogeneous in terms of clinical attributes and the resources used in the provision of care. The records of 2094 patients admitted during 1994-95 to four hospitals in the Illawarra Area Health Service with at least one diabetes diagnosis recorded in the discharge summary were reviewed. We found that the source data used for assignment contained errors of medical documentation, abstraction and sequencing, and coding. The sampled patients were distributed among many AN-DRGs in a way which was neither clinically coherent nor obviously descriptive of resource-use differences. The AN-DRG logic appears to ignore or otherwise under-estimate the effects of diabetes as a secondary diagnosis.

Casemix and nursing.

The American Nurses' Association did not embrace the introduction of diagnosis related groups, believing they would not recognise nursing activity nor acuity and would bring about the economic demise of nursing. Australian nurses, by contrast, recognised the window of opportunity that the work towards Australian national diagnosis related groups and funding mechanisms provided to move nursing resources into the political and policy mainstream. This paper reviews the American and Australian nursing experience with casemix, acuity and cost weighting. It uses examples from more recent work to argue for the use of casemix information in new ways, for 'process improvement' or 'evidence-based management'. The paper concludes that the next great leap forward in casemix may require attention to building the information and human infrastructures, so that the valuable clinical-financial information produced by casemix-based information systems can truly inform management and policy.

Comorbidities and prediction of length of hospital stay.

Variability in length of stay (LOS) within Australian National Diagnosis Related Groups (AN-DRGs) reflects clinical heterogeneity in age, severity of illness, complications and comorbidities. To develop a clinically based score which measures patient morbidity and which will better predict LOS compared to existing methods. ICD-9-CM codes of diseases and procedures were allocated to one of 23 body system categories to calculate the body burden of disease (BBD) score. Evaluation of BBD in predicting LOS was performed using multiple regression and analysis of variance with a data set of 34,079 cases from 75 AN-DRGs from three Victorian hospitals. Adding BBD and age improved prediction of LOS by 27.2% in AN-DRG version 1.0 and by 17.5% in AN-DRG version 3.1. When using average inlier LOS for AN-DRG, BBD and age improved prediction of LOS by 44.6% and by 14.8% in AN-DRG version 1.0 and version 3.1 respectively. Deaths were positively related to BBD. BBD is a simple quantitative measure of extent of disease that improves current methods in accounting for variability in LOS.

Linking measures of health gain to explicit priority setting by an Area Health Service in Australia

A demonstration project was undertaken to develop an integer programming model that could help a regional health authority to take into account data on service effectiveness when allocating resources to acute inpatient services. The model was designed to find the mix of services that would maximise health gain from the available resources, and so provide information that could be used to encourage hospitals to change their patient mix. It was developed in collaboration with an Area Health Service in New South Wales, Australia, with the aim of assessing its potential as a decision support tool. Acute inpatient services were categorised in the model using classes derived from the Australian National Diagnosis Related Groups (AN-DRG) classification and the classes developed by the Oregon Health Services Commission. Estimates for the effectiveness of each service was derived from the Oregon benefit data. Estimates of resource use were derived from AN-DRG data. The expected demand for each service was derived from local activity data. Various scenarios were developed to assess the potential of the model to support decision makers. These mimicked plausible policy options and tested the sensitivity of the results to changes in the data. The scenarios demonstrated the model could reveal the consequences of different policy options, but also suggested that the difference in the cost-effectiveness of services close to the margin would be small and so a rigid approach to priority setting is undesirable. Difficulties in developing the model also demonstrate that incorporating health gain data into resource allocation decisions will not be straightforward for health planners.

Using endoscopic procedures for AN-DRG (Australian National Diagnosis Related Groups) assignment: Australia leads the way.

The study reported in this article sought to develop Australian National Diagnosis Related Groups (AN-DRGs) using endoscopic procedures in Major Diagnostic Category (MDC) 6 (Digestive System) and MDC 7 (Hepatobiliary System and Pancreas) through statistical analysis of the Australian Casemix Clinical Committee's recommendations. Five ANOVA were undertaken on final recommendations for gastroscopy and colonoscopy in MDC 6. The Reduction in Variance (RIV) for the AN-DRGs in version 3 relative to version 2 increased by up to 14.6%, representing RIV of between 25.28% to 32.30%. For all ANOVAs, F > 100, alpha < .0001, Coefficient of Variation (CV) was generally lower in version 3 by between 0.4% to 22.9%, except for AN-DRGs for other gastroscopy for major gastro-intestinal disease, which increased by 8.7%. Two ANOVA for Endoscopic Retrograde Cholangio-pancreatography Procedures (ERCP) recommendations resulted in RIV of up to 18.67%, F > 100, alpha < .0001 and CV up to 0.8091. MDC 6, in AN-DRG versions 3 and 3.1, has 11 AN-DRGs following the surgical hierarchy involving gastroscopy and colonoscopy. Patients assigned will not have an operating room procedure; they will have a non-operating room procedure that is either a complex therapeutic or other (diagnostic or therapeutic) procedure. Similar AN-DRGs are in MDC 7 for ERCP. Version 3.1 has expanded the definition of Common Bile Duct Exploration (CDE) to include ERCP. There is no separate AN-DRG for laparoscopy cholecystectomy.

Reporting of adverse events in hospitals in Victoria, 1994‐1995

To describe the nature and frequency of adverse events (AEs) reported in routine inpatient data collection. Retrospective analysis of data from the Victorian Inpatient Minimum Database. All public (135) and private (112) acute-care hospitals in Victoria, 1994-1995. All patients with separations recording an E-code identified as an AE through the International classification of diseases, ninth revision (ICD-9), classification system. Australian national diagnosis-related groups (AN-DRGs) associated with AEs; prevalence of major organ system disease in each of the AE groups; AE rates by hospital type; and impact of AEs on discharge destination, or death. AEs were recorded in 5% of separations, with incidence increasing with patient age. Most (81%) were complications after surgery or other procedures (E878-E879); 19% were adverse drug effects (E930-E949) and 1.7% were misadventures (E870-E876). The most frequently reported complications were infections, haemorrhage and pneumonia. AN-DRGs--joint replacement of the lower limb, bowel excision and hysterectomy--contributed most to the volume of AEs, while the greatest risk was associated with ventricular shunt, major organ transplantation and surgery for complicated injuries. The in-hospital death rate in patients with AEs was 2.9% (95% confidence interval [95% CI], 2.7%-3.2%), compared with 1.3% (95% CI, 1.0-1.4) in those without an AE. Of patients with an AE, fewer were discharged directly home, and higher proportions were discharged to other acute-care facilities or nursing homes compared with those without an AE. Inpatient data collection can provide information about AE rates associated with individual procedures, and the nature of these AEs. It can be used by hospitals to direct and complement their own quality improvement activities. Its limitation is that it cannot identify the severity or long term outcome of AEs.

Postoperative complications of cholecystectomy in Victorian public hospitals.

Cholecystectomies in Victorian public hospitals were evaluated by analysis of hospital morbidity data. The Victorian Inpatient Minimum Dataset (VIMD) contains data on postoperative complications from all cholecystectomies in Victorian public hospitals. Hospital separations associated with cholecystectomy were identified according to Australian national diagnosis-related groups and the procedures were grouped as open, laparoscopic or conversion from laparoscopic to open cholecystectomy (conversion). Postoperative complications were identified by ICD9-CM external-cause codes (E-codes) in the VIMD. The 35593 cholecystectomies performed between 1987-88 and 1993-94 were analysed. A further detailed analysis of all cholecystectomies performed in 1993 was based on logistic regression. This identified the adjusted odds (AOR) of occurrence of complications and included covariates of age, sex, admission type, diagnosis-related group and hospital identification code. The annual frequency of cholecystectomy increased after introduction of laparoscopic cholecystectomy in 1990, and was associated with an increase in rates of separations having adverse events, but laparoscopic cholecystectomy had the lowest rate (66.7 per 1000 separations). Adverse-event rates for open procedures increased to 157.5 per 1000 in 1993-94, and for conversions to 290.0 per 1000. Of 5627 cholecystectomies in 1993, 74.4 per cent were laparoscopic, 21.5 per cent open and 4.1 per cent conversions. Postoperative complications were more likely in males (AOR 1.67, 95 per cent confidence interval (CI) 1.38 to 2.04), in patients admitted as an emergency (1.27, CI 1.01 to 1.60), and in those having open cholecystectomies (2.25, 1.78 to 2.85) or conversions (4.29, 3.05 to 6.03). Analysis of the VIMD has provided information for the evaluation of cholecystectomy. The VIMD is a useful tool for monitoring postoperative complications and the quality of care in Victorian hospitals.

A casemix for mental health services: the development of the mental health and substance abuse components of the Australian national diagnosis-related groups.

To describe the development of the mental health and substance abuse sections of the version of the Australian casemix system, Australian national diagnosis-related groups 3 (AN-DRG 3), released in July 1995. The guiding principles and data sources used to construct the mental health and substance abuse components of AN-DRG 3 are described by the group who undertook that task. The group used data sets of patients separating from hospitals throughout Australia, and from hospitals in South Australia, to examine the capacity of existing and revised diagnosis-related groups (DRGs) to predict patients' lengths of hospital stay. They also reviewed the lists of conditions allowed as complicating and comorbid conditions within the AN-DRG system. A variety of recommendations were made including: moving organic mental disorder DRGs to a neuroscience area of the AN-DRG; completely reorganising the mental health section of the casemix; creating a number of narrowly defined DRGs covering areas such as schizophrenia, major affective disorders, anxiety disorders and eating disorders, while allowing for a limited number of more heterogenous DRGs and simplifying substance abuse DRGs into groups covering alcohol and other substances, and differentiating intoxication and withdrawal from abuse and dependency. A casemix dialect based on clinical diagnosis, which describes mental health and substance abuse problems in terms which should be familiar to clinicians, has been developed. Its applications and limitations are briefly discussed.

Casemix classification and health care of the elderly.

The Australian national diagnosis-related groups (AN-DRGs) patient classification has highlighted the distinction between different categories of inpatient care and ambulatory care, and the need for an explicit definition of boundaries of associated categories. A nationally consistent definition of these patient care categories, and of episodes of care according to illness acuity, will facilitate the design of additional casemix classifications to supplement AN-DRGs. Specific features of the AN-DRGs classification will have a major impact on health care of the elderly through incentives created by funding arrangements based on this classification. The use of age as an AN-DRG classification criterion, as a surrogate for definitive secondary diagnoses, should be regarded as an interim measure pending improvement in medical record documentation, further analysis of the relationship of age partitions to these secondary diagnoses, and ongoing improvement of AN-DRG design. The complex process of development of casemix classifications for subacute and ambulatory care has commenced, and will also have a profound impact on health care of the elderly and on all specialities concerned with both acute and chronic illness, again because of financial incentives in the classification design. Funding for development and refinement of each of these casemix classifications will be required if the anticipated benefits are to occur.

The implementation of casemix in Victoria — a clinician's view

Although a number of concerns remain, casemix-based funding is seen by clinicians in Victoria to be a more equitable way of determining public hospital inpatient budgets than historical allocation, and will provide a valuable source of data for service provision planning. The concerns in particular are the inadequacy of the current Australian national diagnosis-related groups 2 system to classify modern clinical practice and describe complex patients; the absence of adequate baseline data to allow an accurate assessment of the impact of casemix-based funding on quality of care; the lack of direct recognition within diagnosis-related groups of the training, research and development roles of public hospitals; and the instability of a funding system which is in evolution.

Making casemix work for psychiatry.

Providers of mental health and substance abuse care cannot afford to ignore the existence of casemix descriptions of their services. As casemix comes to be the predominant language used to describe the products of hospital care, its use will inevitably impinge upon psychiatric services. The psychiatric components of the Australian national diagnosis-related groups classification 1 and 2 (AN-DRG 1 and 2) do not describe the relevant products with great accuracy. We review some possible reasons for this and the effects on the homogeneity of resource consumption of technical procedures, such as trimming of data sets, in the context of the current casemix system and that proposed for AN-DRG-3. The evolution of a casemix system which does justice to current and future psychiatric services will be a complex process. Some of the crucial areas are discussed. Clinicians involved in mental health and substance abuse care must continue to advocate for the resources and effort needed to improve casemix information in their area.

Clinical representation in the development of casemix: measures and applications in Australia.

The Australian Casemix Clinical Committee coordinated the clinical evaluation of inpatient casemix classifications leading to the development of Australian national diagnosis-related groups 1, 2 and 3. It has provided and will continue to provide advice on clinical matters associated with casemix activities to the Commonwealth and State health authorities, public and private hospital associations, insurers and the clinical professions. In future, all clinicians will be expected to understand casemix, diagnosis-related groups and cost weights, especially those relevant to their speciality.