Development and application of a method for estimating daily case-mix adjusted costs of adult critical care units.

摘要

Patients referred for treatment in an adult critical care unit are in, or atudimminent risk of developing single or multiple organ failure. Despiteudthe high treatment costs, knowledge of the costs of care is limited. Theudaims of this thesis were to synthesise current knowledge about theuddifferent methods used to estimate costs and to develop and apply audmethod for estimating daily case-mix adjusted costs for developing audset of Healthcare Resource Groups (HRGs) and for use in a trial-basedudeconomic evaluation. HRGs were required to support the Departmentudof Health's new policy on reimbursing adult critical care calledud'Reforming NHS Financial Flows: Introducing Payment By Results'.udA systematic review of 20 published studies provided the backgroundudto, and justification for the methods employed in two empirical studies.udThe first empirical study was performed in a single critical care unitudand using very detailed data on individual patients evaluated factorsudthat had the potential to correlate with daily costs of critical care.udUnivariate and multivariate statistical analyses were undertaken usingudtwo different data sets. Patients' daily organ supports were identified asudthe key 'cost generating events'. A prospective, observational,udlongitudinal multi-centre study involving a volunteer sample of 70udcritical care units followed, where organ support data on 7,243udconsecutive admissions and monthly data on critical care unitudexpenditure were collected. Different ways of modelling the organudsupport and expenditure data were explored. The overall R2 for theudchosen model- the daily number of organs supported was 0.52. Dailyudorgan support weights for the average daily costs of critical care wereud0.577 for 0 or 1 organ supported, 1.137 for 2 organs supported andud1.156 for 3 or more organs supported. These weights were then appliedudto average daily costs estimated for patients recruited to a clinical trialudof Extracorporeal Membrane Oxygenation (ECMO) vs. conventionaludtherapy for severe, but potentially reversible, respiratory failure.