Effect of Healthcare-Acquired Infection on Length of Hospital Stay and Cost

Objective: To estimate the independent effect of a single lower respiratory tract, urinary tract, or 'other' healthcare-acquired infection on length-of-stay and variable costs, and to demonstrate the bias from omitted variables present in previous estimates. Design: Prospective cohort study Setting: A tertiary referral hospital and regional district hospital in South-East Queensland, Australia Patients: Adults ≥ 18 years of age with a minimum inpatient stay of one night admitted to selected clinical specialities Results: Urinary tract infections were not associated with an increase in length of hospital stay or variable costs. Lower respiratory tract infection was associated with an increase of 2.58 days in hospital and $AU24 of variable costs, whilst ‘Other’ sites of infection were associated with an increased length-of-stay of 2.61 days but not variable costs. Many other factors were found to be associated with increased length of stay and variable costs alongside HAI. The exclusion of these variables caused a positive bias in the estimates of the costs of HAI. Conclusions: The existing literature may overstate the costs of HAI due to bias and the existing estimates of excess cost may not make intuitive sense to clinicians and policy makers. Accurate estimates of the cost of HAI should be made and used in appropriately designed decision-analytic economic (i.e. cost-effectiveness) models that will make valid and believable predictions of the economic value of increased infection-control