A medical service requirements model for health system design

In response to the medical conditions presented by patients, physicians call for a number of services such as lab tests, special therapy, bed rest, and physiologic monitoring. These services, delivered within a variety of institutional settings, account for over half of the cost of medical care. The physician's selection of a care regimen for a patient is currently constrained by traditional health service delivery patterns already existing in the community. Forecasting the demand for services on the basis of these traditional patterns, therefore, will tend to perpetuate current practice. This paper develops a model of physicians' demands for health services based on medical judgment of required and acceptable care for specific medical conditions. The model provides a convenient framework for abstracting medical opinion in the form of patient-states, care requirements, and disease dynamics. From this data the model determines the time-varying census of patients in each patient-state and generates the time stream of elementary services required to support the medical care of a population. The demand model was developed to assist the innovation of new forms of health service delivery; it may be used to predict the loads on individual service units in service systems that depart from traditional practice.