Pharmacoeconomic consequences of measurement and modification of hospital drug use.

Patterns of drug usage affect hospital-based delivery of healthcare in a variety of ways. Adverse reactions to drugs (ADR) precipitate some 5% of admissions and prejudice the care of some 20% of patients who are in hospital, while inadequate drug therapy prejudices outcomes and prolongs hospital stay. Conversely, appropriate application of drugs can promote recovery and increase the quality of care. Well documented examples include prevention of deep vein thrombosis and postoperative wound infections. Accordingly, optimisation of drug use represents a major quality assurance issue in addition to determining cost-efficiency of healthcare delivery. Drug utilisation review (DUR) requires all elements of the quality assurance process. In practice, therapeutically meaningful and cost-efficient exercises can only be mounted if there is knowledge of the linkage between patterns of drug use and clinical outcomes. These processes of measurement are currently rate-limiting in quality assurance. There are various ways that hospital drug usage can be measured. These range from readily available and relatively cheap quantitative methods to methods requiring the availability of expert staff. There is a sequence of methods involving increasing costs and increasing resource demands yielding increasing detail of information obtained. This sequence commences with pharmacy purchases, followed by pharmacy issues to particular clinical areas, prescription or treatment sheet survey, clinical record review, and finally the reports of trained investigators working in the clinical area. The simpler methods can provide useful information and an efficient basis for choosing and planning definitive studies. Once a category of drug use is appropriately targeted for intervention, drug use can be modified by planned intervention with improvement in clinical outcomes and reduced economic costs in many instances. The intervention strategies to modify drug usage may be classed as re-educative, persuasive, facilitative and power strategies. Other models for implementing behavioural change have been considered, including the impact of trained investigators and the use of online computer prescribing with interactive software with appropriate guidelines. The challenge is to achieve sustained change when interventions are implemented. Cost-efficient quality assurance of drug use is possible with modest resources if outcome-orientated activities are prioritised.