GERIATRIC-PATIENT FLOW-RATE MODELING

We consider the application of a three-compartment mathematical model using difference equations in discrete time to model the flow of patie nts through departments of geriatric medicine. It has been shown empir ically that the time spent in hospital since admission may be describe d by a two-term mixed-exponential distribution. Previous work has expl ained this empirical finding in terms of a two-compartment model of ge riatric in-patient behaviour where the two compartments are acute/reha bilitative and long-stay care. Our model extends this approach by cons idering patients released from geriatric departments and their subsequ ent length of stay in the community. We have therefore, two states of patient behaviour while in hospital: (i) patients can be admitted to t he acute-rehabilitative state, from which they may die or be released back into the community; (ii) patients can be admitted to the long-sta y state, from which they eventually die. The community state currently has only one state, from which patients may be readmitted back into t he geriatric department or they may die. The model may then be used to estimate the average numbers and lengths of stay for short-term and l ong-term patients and the average number and length of stay in the com munity for released patients, allowing for a significant improvement i n the forecasting of future bed requirements to aid the planning of ge riatric departments.