US Hospital Use of Echocardiography
What are the trends in use of echocardiography (echo) and patient outcomes through assessment of hospitalizations available in the Nationwide Inpatient Sample (NIS) database?
The NIS database was queried for inpatient echo use between the years 2001 and 2011 to assess trends and use. Data from calendar year 2010 were evaluated in detail for use of echocardiography for eight separate admitting diagnoses including acute myocardial infarction (AMI), cardiac dysrhythmia, acute cerebrovascular disease, congestive heart failure (CHF), coronary artery disease (CAD), sepsis, valvular heart disease, and nonspecific chest pain. Exclusions included neonatal patients, hospitalizations <24 hours, and nonemergency department admissions. The patient sample was stratified by primary admission diagnosis as well as demographics of age, race, sex, insurance status, number of comorbidities, and illness severity score, among others. The primary endpoint was in-hospital mortality. The 2010 patient sample database was dichotomized into hospitalizations in which echo was or was not performed. For further validation, the authors performed a similar analysis on patients admitted to their home institution in calendar year 2014.
From 2001 to 2011, approximately 7,669,000 echos were performed in the NIS population, representing an average annual rate of increase of echocardiography of 3.41%. Comparison of echo use of patient outcomes found that hospitalizations in which echo was performed had declining rates of hospital mortality and length of stay, but rising hospitalization charges. State-by-state analysis revealed higher rates of echo use throughout the East Coast compared to other states. For the 2010 data, 816,500 echos were performed, corresponding to 2.09% of all hospital admission, but 7.01% of hospitalizations for the identified admitting diagnoses studied. Patients receiving echo were younger, received more cardiac stress tests, resided in higher income zip codes, had higher risk of mortality, and more medical morbidities (all p < 0.001). echo use varied among the studied diagnoses, and was utilized in 22% of valvular disease, 12% of acute cerebrovascular disease, 10% of cardiac dysrhythmia, 7% of CHF, 6% of AMI, 6% of CAD, and 5% of sepsis. Use of echo was associated with lower odds of all-cause hospital mortality and AMI (odds ratio [OR], 0.74; p < 0.001), cardiac dysrhythmia (OR, 0.72; p = 0.02), acute cerebrovascular disease (OR, 0.36; p < 0.001), CHF (OR, 0.82; p = 0.005), and sepsis (OR, 0.77; p < 0.001). There was no significant difference in mortality in subsamples for CAD, valvular heart disease, or nonspecific chest pain. For the author’s home institution, use of echo increased at an average annual rate of 4.75% for 2003-2014. For the calendar year 2014, 18,401 hospitalizations were for 1 of the 8 admission diagnoses. Within the single-center database, 25% of AMI patients were discharged without echo. There was no statistically significant increase in mortality in patients without echo (10.1% vs. 9.1%).
There is an increase in echo use overall within the NIS database; however, echo may be underused during cardiac-specific admissions. Use of echo was associated with decreasing patient mortality.
This study confirms the increase in overall use of echo in a large nationwide database. The increase in echo use in this database is less than that previously reported from a Medicare population. The authors appropriately point out a number of limitations of using the NIS database including a probable underreporting of echo performance at the time of evaluating discharge. With these limitations in mind, it appears there is still an underuse of echo in select cardiac diagnoses where performance of an echocardiogram would be expected to be standard of care including AMI and CHF. While there was an association of declining inpatient mortality with performance of echo, causality cannot be proven as other variables such as sophistication of the care cannot be controlled for. Although limited by methodological issues inherent in this database, the results reported here are quite striking with respect to apparent underuse of echocardiography in multiple disease states for which the appropriate use criteria have supported its use, and probably warrant further evaluation in a database providing more robust information regarding precise use of echocardiography and alternate imaging techniques.
Clinical Topics: Acute Coronary Syndromes, Arrhythmias and Clinical EP, Heart Failure and Cardiomyopathies, Noninvasive Imaging, Valvular Heart Disease, Vascular Medicine, Atherosclerotic Disease (CAD/PAD), Implantable Devices, SCD/Ventricular Arrhythmias, Atrial Fibrillation/Supraventricular Arrhythmias, Acute Heart Failure, Echocardiography/Ultrasound
Keywords: Acute Coronary Syndrome, Arrhythmias, Cardiac, Cerebrovascular Disorders, Chest Pain, Coronary Artery Disease, Diagnostic Imaging, Echocardiography, Hospital Mortality, Heart Failure, Heart Valve Diseases, Inpatients, Myocardial Infarction, Sepsis
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