Hospital length of stay and probability of acquiring infection

Hospital‐acquired infection (HAI) poses important health and financial problems for society. Understanding the causes of infection in hospital care is strategically important for hospital administration for formulating effective infection control programs. The purpose of this paper is to show that hospital length of stay (LOS) and the probability of developing an infection are interdependent.

A two‐equation model was specified for hospital LOS and the incidence of infection. Using the patient‐level data of hospital discharge in the State of New Jersey merged with other data, the parameters of the two equations were estimated using a simultaneous estimation method.

It was found that extending the LOS by one day increases the probability of catching an infection by 1.37 percent and the onset of infection increases average LOS by 9.32 days. The estimation indicates that HAI elongates LOS increasing the cost of a hospital stay.

The findings imply that studies on cost of HAI that do not properly control for the simultaneity of these two variables, will result in a biased estimation of cost.

The study produces quantitative estimation of the extent of interdependency of hospital LOS and the probability of catching an infection.