Radiology imaging delays as independent predictors of length of hospital stay for emergency medical admissions

doi:10.1016/j.crad.2016.03.023

Clinical Radiology

Volume 71, Issue 9, September 2016, Pages 912-918

https://doi.org/10.1016/j.crad.2016.03.023 Get rights and content

Highlights

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There are differing clinical complexities for patients depending on the modality.
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A predictive risk model, incorporating advanced imaging, was devised.
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Inpatients delays in radiology imaging associated with longer LOS.
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Inpatients who underwent radiology imaging associated with increased hospital costs.

Aim

To investigate the extent to which the time to completion for computed tomography (CT), magnetic resonance imaging (MRI), and ultrasound could be shown to influence the length of stay and costs incurred while in hospital, while accounting for patient acuity.

Materials and methods

All emergency admissions, totalling 25,326 imaging investigations between 2010–2014 were evaluated. The 50^th, 75^th, and 90^th centiles of completion times for each imaging type was entered into a multivariable truncated Poisson regression model predicting the length of hospital stay. Estimates of risk (odds or incidence rate ratios [IRRs]) of the regressors were adjusted for acute illness severity, Charlson comorbidity index, chronic disabling disease score, and sepsis status. Quantile regression analysis was used to examine the impact of imaging on total hospital costs.

Results

For all imaging examinations, longer hospital lengths of stay were shown to be related to delays in imaging time. Increased delays in CT and MRI were shown to be associated with increased hospital episode costs, while ultrasound did not independently predict increased hospital costs. The magnitude of the effect of imaging delays on episode costs were equivalent to some measures of illness severity.

Conclusion

CT, MRI, and ultrasound are undertaken in patients with differing clinical complexity; however, even with adjustment for complexity, the time delay in a more expeditious radiological service could potentially shorten the hospital episode and reduce costs.

Introduction

The recent increased demand for advanced radiology imaging has been well documented.1, 2, 3 The necessity of this demand growth has been examined through investigations on how imaging may affect or relate to outcomes, length of hospital stay, and costs.3, 4, 5, 6, 7 Increased utilisation of inpatient computed tomography (CT) and magnetic resonance imaging (MRI) has been associated with lower mortality and with a decrease in hospitalisation costs, albeit with a marked increase in imaging costs.3, 4 Patient outcome and length of hospital stay for specific emergency department (ED) and stroke cohorts have been related to the timing of advanced radiology scanning,5, 6, 7 while early advanced imaging has been identified as influencing length of stay, evidenced as significantly shorter length of stay for early CT or MRI.³

The literature, however, has been lacking in quantitative analysis relating to turnaround times and length of stay. There are particular methodological issues with investigating the extent to which the time element in the completion of imaging investigations influence the length of hospital episode. Firstly, allowance has to be made for the clinical complexity, which will be the main determinant of length of stay: more complex cases will require more investigations. Secondly, the predictor (the imaging time component) and the response variable (length of hospital stay) are related. Accordingly, a large database detailing all emergency medical admissions at St James's Hospital, Dublin, between 2002 and 2014 inclusive was examined, which contains advanced imaging details and cost details for the last 5 years. The purpose of the present study was to examine the extent to which the time to completion of CT, MRI, and ultrasound imaging could be shown to influence the length of hospital stay and total episode costs, while accounting for patient acuity.

Section snippets

Background

The institution studied in this work serves its local catchment area of 270,000 adults, as a secondary-care centre for emergency admissions. Emergency medical admissions come via the ED to an acute medical assessment unit, which have been described elsewhere.8, 9

Data collection

An anonymous patient database consisting of information of each clinical episode was collated from the patient administration system, the patient electronic record, the emergency room, laboratory systems, and the national hospital

Patients

Twenty thousand, five hundred and four unique patients, admitted via the ED, representing all emergency medical admissions during 2010–2014, underwent a total of 25,326 imaging investigations. The median length of stay (IQR) was 5.0 (2.01, 9.7) days. The median age (IQR) was 62.8 (43.1, 78.1) years. The proportion of males was 48.6%. The Charlson comorbidity score of 0, 1, or 2 was present in 44.8%, 29.7%, and 25.4%, respectively. The major disease categories were respiratory (24.7%),

Discussion

The aim of the present study was to investigate the extent to which MRI, ultrasound, and CT radiology turnaround times affected length of hospital stay and hospital costs. This was performed against a backdrop of growing MRI, ultrasound, and CT inpatient imaging demand, having increased by 19%, 11%, and 22%, respectively, between 2010 and 2014 at St James's Hospital. Hence, this prompted the consideration of whether current capacities at St James's Hospital were adequate for the growing demand.

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In this IRB-approved, retrospective cohort study, approximately one month of imaging recommendations were reviewed from 2017 at a single academic institution that contained key words recommending follow-up imaging. Age, gender, race/ethnicity, insurance, smoking history, primary language, BMI, and home address were recorded via chart extraction. Home addresses were geocoded to Census Block Groups and assigned to a quintile of neighborhood socioeconomic status. A multivariate logistic regression model was used to evaluate each predictor variable with significance set to p = 0.05.
A total of 13,421 imaging reports that included additional follow-up recommendations were identified. Of the 1013 included reports that recommended follow-up, 350 recommended additional imaging and were analyzed. Three hundred eight (88.00%) had corresponding follow-up imaging present and the insurance payor was known for 266 (86.36%) patients: 146 (47.40%) had commercial insurance, 35 (11.36%) had Medicaid, and 85 (27.60%) had Medicare. Patients with Medicaid had over four times lower odds of completing follow-up imaging compared to patients with commercial insurance (OR 0.24, 95% CI 0.06–0.88, p = 0.032). Age, gender, race/ethnicity, smoking history, primary language, BMI, and neighborhood socioeconomic status were not independently associated with differences in follow-up imaging completion.
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The time taken from clinician ordering to radiology scan interpretation time is an important quality measure that can impact hospital workflow and patient outcomes. Delays in performing radiology scans or interpreting them can prolong the time until a proper treatment decision can be made, leading to increased costs and potential compromises in patient care (1). During non-business hours at our institution, the impact can be especially notable as a smaller number of radiologists is present, that often consists of radiology trainees or nighthawks instead of subspecialty attending radiologists.
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View all citing articles on Scopus

View full text

Radiology imaging delays as independent predictors of length of hospital stay for emergency medical admissions

Highlights

Aim

Materials and methods

Results

Conclusion

Introduction

Section snippets

Background

Data collection

Patients

Discussion

J Am Coll Radiol

J Am Coll Radiol

J Am Coll Radiol

J Chronic Dis

Organ Soc Vol

Eur J Intern Med

J Am Coll Radiol

The new era of medical imaging—progress and pitfalls

N Engl J Med

Diagnostic imaging costs: are they driving up the costs of hospital care?

Radiology

Effect of testing and treatment on emergency department length of stay using a national database

Acad Emerg Med

The effect of imaging capacity on the imaging workup of patients with stroke: a preliminary case for a cross-country comparison

J Am Coll Radiol

Impact of an acute medical admission unit on hospital mortality: a 5-year prospective study

Q J Med