Computed tomography scan use variation: patient, hospital, and geographic factors

To examine patient, hospital, and geographic characteristics influencing variation in computed tomography (CT) scan use in inpatients in New York State.

Retrospective cohort study.

We used the 2007 healthcare cost and utilization project's state inpatient database from the agency for healthcare research and quality and applied descriptive univariate statistics and logistic regression models to quantify the influence of each factor on CT scan use.

The primary contributors to variation in CT scan use were the inpatients' diagnosis, age, and hospital county, whereas inpatients' sex and method of payment and hospitals' teaching status and size had very little effect. Inpatients diagnosed with trauma had the highest CT scan use; CT scan use increased with age for inpatients over 30 years; and CT scan use varied widely between counties.

After controlling for patient and hospital characteristics, significant geographic variation remained at the level of the county, which indicates that additional research investigating the use of CT scans is necessary to understand the reasons behind small-area variation. Understanding the distribution and practice patterns of specific physician specialties may be helpful in curtailing underuse and overuse.