Objectives: to assess whether measures of cognitive and physical function can explain differences in observed and healthcare resource group (HRG) predicted length of stay for patients presenting with six target conditions at admission.
Design: prospective observational study.
Setting: three East Kent district general hospitals.
Participants: One thousand nine hundred and forty-two consecutive emergency admissions, from March to July 2004, with ne or more of six presenting conditions (stroke, fracture neck of femur, myocardial infarction, acute respiratory infection, chronic obstructive airways disease and falls).
Main outcome measures: length of stay by physical and cognitive function score adjusted for HRG allocated at discharge and other covariates. Physical function was defined using Activities of Daily Living Hierarchy Scale and cognitive function using the Cognitive Performance Scale.
Results: median difference between observed and HRG predicted length of stay was 1.2 days (25th percentile estimate, 3.9; 75th percentile estimate, 10.1) for patients with high physical dependency. They stayed 40% longer (95% confidence interval 26-56%) than patients with lower physical dependency after excluding effects of HRG and other covariates. Results are not consistent for cognitive function scores, mainly because most patients had no cognitive impairment.
Conclusions: these patients, presenting with conditions common in older patients, would have incurred estimated annual costs of pound 1.9 million in excess of their HRG tariff-based re-imbursement. Physical function, defined by the degree of dependency in activities of daily living, should be incorporated into HRGs to reduce the financial risk faced by acute hospital services under Payment by Results, the UK diagnosis related group re-imbursement system.