DRUG-USE IN RELATION TO CLINICAL ACTIVITIES AS AN INSTRUMENT FOR PROSPECTIVE DRUG BUDGETING - THE BELGIAN EXPERIENCE

In an effort to control escalating health expenditures, especially in hospitals, many countries are planning or experimenting with prospecti ve budgeting systems. Belgium is no exception and has recently introdu ced, with some success, limited fixed charges per hospital admission a nd/or per hospitalisation day for laboratory tests and radiographic in vestigations. More recently, the focus has shifted to hospital drug ex penditures, which have shown high growth rates over the past few years . Until now, such expenditures have been reimbursed on a fee-for-servi ce system, often with limited out-of-pocket charges far hospitalised p atients. In order to curb the growth of drug expenditures, it is appro priate to investigate whether the financing of hospital drugs through a prospective budgeting system could be a feasible solution. Therefore , we constructed a database of over 270 000 admissions from a sample o f 23 Belgian general and teaching (university) hospitals for the year 1991. Data were obtained from the official Minimum Basic Data Set or R esume Clinique Minimum, which contains summarised clinical and adminis trative information, plus detailed expenditures (including medications ) for each hospital stay. This information allowed us to categorise ea ch stay into an appropriate diagnosis-related group (DRG). Our first d escriptive analysis identified a number of major variables that influe nced patients' drug expenditures: all-patient DRG (APDRG), age, diseas e severity, length of stay in an intensive care unit, emergency admiss ion, death during hospitalisation, and hospital type (teaching or gene ral). A covariance analysis was then performed on all hospital stays c ombined, and separately on surgical and medical stays. The results ind icated that these variables taken together account for between 56.5 an d 76.3% of drug expenditures in medical and surgical stays, respective ly, with the major variance explained by differences in APDRG category . However, when the data were disaggregated according to major diagnos is category, a large degree of heterogeneity in the explained variance was observed. In patients with drug use- and alcohol-related disorder s, 5.2% of drug billings/expenditures were attributable to the APDRG, and the corresponding figure in patients undergoing circulatory system surgery was 84%. This means that, if DRGs are used to define a global prospective drug budget for a hospital, using the hospital's historic al case mix as a weighting factor, we should pay particular attention to the hospital profile because the predictive power of such a system could be relatively low in some hospitals. Consequently, we need to co nstruct larger confidence intervals for hospitals in which historical drug expenditures have low predictive power, or search for additional explanatory variables for expenditures in these hospitals.