Trends in Use of Daily Chest Radiographs Among US Adults Receiving Mechanical Ventilation

Abstract

Importance: Guidelines from December 2011 recommended against obtaining daily chest radiographs (CXRs) for patients requiring mechanical ventilation (MV). Daily CXR use for patients receiving MV in US hospitals is unknown and, if high, may represent an opportunity to reduce low-value care and unnecessary radiation.

Objectives: To determine frequency of daily CXR use for US patients receiving MV, assess variability across hospitals, and evaluate whether use has decreased over time.

Design, setting, and participants: Retrospective cohort study of hospitalized adults (aged ≥18 years) receiving MV for 3 days or longer. Mechanical ventilation was defined by having an International Classification of Diseases, Ninth Revision, Clinical Modification code of 96.7x and an MV charge on more than 1 hospital day. Hospital discharges in the Premier Perspectives database were examined from July 1, 2008, to December 31, 2014. Data analysis was conducted from July 28, 2017, to December 13, 2017.

Exposures: Hospital discharge date (quarter of the year) and hospital in which patients received MV.

Main outcomes and measures: The outcome was daily CXR use (up to 7 days) during MV. We used standard statistics to describe CXR use, multilevel multivariable regression modeling with adjusted median odds ratio (OR) to evaluate variability by hospital, and multivariable piecewise regression (breakpoint: fourth quarter of 2011) with adjusted OR to evaluate time trends and response to guideline recommendations.

Results: The primary cohort included 512 518 patients receiving MV (mean [SD] age, 63.0 [16.1] years; 46% female) in 416 hospitals, of whom 321 093 (63%) received daily CXRs. Wide variability was seen across hospitals; hospitals performed daily CXRs on a median of 66% of patients (interquartile range, 50%-77%; full range, 12%-97%). The adjusted median OR was 2.43 (95% CI, 2.29-2.59), suggesting the same patient had 2.43-fold higher odds of receiving a daily CXR if admitted to a higher- vs lower-use hospital; the odds of receiving daily CXRs were unchanged through quarter 3 of 2011 (adjusted OR, 1.00; 95% CI, 0.99-1.01), after which there was a 3% relative reduction in the odds of daily CXR use per quarter (adjusted OR, 0.97; 95% CI, 0.96-0.98).

Conclusions and relevance: Three-fifths of US patients receiving MV also received daily CXRs from 2008 to 2014, although use declined slowly after new guidelines were published. The hospital at which a patient received care was associated with the odds of daily CXR receipt.

Figure 1.. Flow Diagram

ICD-9 indicates International Classification of Diseases, Ninth Revision; MV, mechanical ventilation.

Figure 2.. Percentage of Patients Receiving a Chest Radiograph (CXR) Every Day (Up to 7 days) Following Mechanical Ventilation (MV) Initiation Stratified by Individual Hospital

Each gray bar indicates an individual hospital; blue line, median value across all hospitals; and orange lines, 25th and 75th percentile values across all hospitals.

Figure 3.. Adjusted Association of Individual Hospital and Discharge Quarter With the Receipt of a Chest Radiograph (CXR) Every Day Following Mechanical Ventilation (MV) Initiation

All models are multilevel multivariable logistic regression except for the primary cohort, CXR every day up to 14 days, for which the model did not converge and a single-level multivariable logistic regression model with clustering of standard errors by hospital was used. Covariates adjusted for in addition to discharge quarter (modeled as a linear predictor) include age, sex, race, insurance provider, number of Elixhauser comorbidities, major surgery, major diagnostic category, hospital bed number, hospital teaching status, urban hospital, and geographic region. Cardiac surgery was defined using Medicare Severity–Diagnosis Related Group (those suggested by Center for Medicare and Medicaid Services; 216-244, 246-265, 215, and 245). On forest plots, markers indicate point estimates; error bars, 95% confidence intervals. The x-axis is on a logarithmic scale. ICU indicates intensive care unit; OR, odds ratio.

Figure 4.. Percentage (Unadjusted) of Patients Receiving a Chest Radiograph (CXR) Every Day (Up to 7 days) Following Mechanical Ventilation (MV) Initiation by Discharge Quarter

Trends in daily CXR use over time were not statistically significantly different across MV duration groups, with P = .22 to .62 for the interaction of MV duration and discharge quarter in a model with percentage of daily CXR use as the independent variable and MV duration, discharge quarter, and their interaction as the dependent variables. ACR indicates American College of Radiology.