This study aimed to assess long-term resource utilization and outcomes in patients with acute chest pain who underwent coronary computed tomography angiography (CCTA) and stress echocardiography (SE). This was a retrospective, propensity-matched analysis of health insurance claims data for a national sample of privately insured patients over the period January 1, 2011, to December 31, 2014. There were 3,816 patients matched 1:1 who received either CCTA (n = 1,908) or SE (n = 1,908). Patients were seen in the emergency department (ED) between January 1, 2011, and December 31, 2011 with a primary diagnosis of chest pain and received either CCTA or SE within 72 hours as the first noninvasive test and maintained continuous enrollment in the database from the time of the ED encounter through December 31, 2014. All individual patient data were censored at 3 years. Compared with SE, CCTA was associated with higher odds of downstream cardiac catheterization (9.9% vs 7.7%, adjusted odds ratio [AOR] 1.28, 95% confidence interval (CI) 1.00 to 1.63), future noninvasive testing (27.7% vs 22.3%, AOR 1.22, 95% CI 1.05 to 1.42), and return ED visits or hospitalization for chest pain at 3 years (33.1% vs 24.2%, AOR 1.37, 95% CI 1.19 to 1.59). There were no statistically significant differences in new statin use (15.5% vs 14.9%, AOR 1.04, 95% CI 0.85 to 1.28), coronary revascularization (2.7% vs 2.2%, AOR 1.25, 95% CI 0.77 to 2.01) or hospitalization for acute myocardial infarction (0.9% vs 0.9%, AOR 0.96, 95% CI 0.47 to 1.99). In conclusion, in patients who present to the ED with chest pain, CCTA is associated with increased downstream resource utilization compared with SE with no differences in long-term cardiovascular outcomes.
Current guidelines recommend the use of noninvasive cardiac testing for emergency department (ED) patients with chest pain who have had negative serial electrocardiograms (ECGs) and cardiac troponins before or shortly after discharge from the ED. Analyses using national claims data indicate that there is significant hospital- and regional-level variation in the rate of testing and choice of test. A meta-analysis of randomized controlled trials (RCTs) that divided studies on the basis of acute versus stable chest pain found that in trials involving patients with acute presentations, the risk of death, nonfatal myocardial infarction (MI), and hospitalization after index encounter was the same for patients randomized to coronary computed tomography angiography (CCTA) versus functional stress testing. CCTA was associated with more cardiac catheterization and revascularization procedures, and new coronary artery disease diagnoses. However, these trials were limited by short follow-up (5 months on average) and type II error. Comparative data on resource use and outcomes for acute chest pain patients who underwent CCTA versus stress echocardiography (SE) are lacking. Only 2 small RCTs have directly compared CCTA with SE. Neither reported a significant difference in downstream cardiovascular events. We sought to expand on these trials by comparing resource use and outcomes in a large, propensity-matched cohort of acute chest pain patients who underwent either CCTA or SE using a national claims database with complete 3-year follow-up.
The use of MarketScan Commercial Claims and Encounters data requires a license for use and thus, the authors are unable to make the raw data publicly available. However, it is available to any patient or institution who actively carries or purchases a license. Patients or institutional users with a license should be able to follow the later methods to replicate the analysis and we fully support outside efforts aimed at replication.
This study was approved by the institutional review board at Penn State Milton S. Hershey Medical Center. The study used MarketScan Commercial Claims and Encounters data from 2010 to 2014. The decision to stop collecting data on December 31, 2014, was made to avoid coding errors and inconsistencies related to the change from International Classification of Diseases, Ninth Revision to International Classification of Diseases, Tenth Revision, which occurred in 2015. MarketScan is constructed and maintained by Truven Health and consists of reimbursed health care claims for employees, retirees, and their dependents of over 250 medium and large employers and their health plans from across all 50 states and the District of Columbia. The database includes a population of approximately 58 million and captures administrative claims with patient-level deidentified data from inpatient and outpatient visits and filled prescriptions. Diagnosis codes use the International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM). Procedures are identified by ICD-9-CM codes in the inpatient files and by Current Procedural Terminology (CPT) codes in the carrier and outpatient claims files.
Patients were included if they met the following criteria: had an ED encounter with a primary diagnosis of chest pain (ICD-9-CM code 786.50) during the period January 1, 2011, to December 31, 2011; underwent CCTA or SE (inpatient or outpatient) within 72 hours of the index encounter; and maintained continuous enrollment from the time of the index encounter through December 31, 2014. Data collection for all patients was censored at 3 years. Patients could only be included as a unique case one time during the study period.
All outpatient, inpatient, and pharmacy claim records within 1 year before the index test were queried to ascertain data on covariates. A history of diabetes was attributed to patients with either ICD-9-CM codes (250.xx) or a medication claim for any diabetes related medication as described previously. Hypertension was attributed to patients with either ICD-9-CM codes (401 to 404) or a medication claim for any antihypertensive medication as described previously. High cholesterol was attributed to patients with either ICD-9-CM codes (272.0, 272.2, and 272.4) or a medication claim for any cholesterol lowering medication as described previously. Statin use was attributed to patients with any medication claim for a statin drug, which were included in the list of medications for any cholesterol lowering medication described previously. Ischemic heart disease was attributed to patients with ICD-9-CM codes for acute MI (410.xx), old MI (412), or ischemic heart disease (414.xx). Inpatient status was attributed to patients whose index chest pain encounter was associated with inpatient admission.
All end points were tracked over the period January 1, 2011, through December 31, 2014 after the index test. Based on the inclusion criteria, all patients had at least 3 years of follow-up data and all patient data were censored at the 3-year mark. Inpatient and outpatient claims were used to document receipt of cardiac catheterization (CPT codes [93451 to 93464]; ICD-9-CM codes [37.22 to 37.23]), percutaneous coronary intervention (CPT codes [92980 to 92996]; ICD-9-CM codes [0.66, 36.01 to 36.09]), and coronary artery bypass surgery (ICD-9-CM codes [36.10 to 36.19]). Inpatient and outpatient claims were also used to document any return ED visit or hospitalization for a primary diagnosis of chest pain (ICD-9-CM code 786.50) or receipt of another noninvasive cardiac imaging study after the index test. CPT codes were used to identify receipt of exercise ECG (EE; 93015, 93016 to 93018), SE (93350), myocardial perfusion imaging (78452), and CCTA (75574). Inpatient claims only were used to document hospitalizations for acute MI. Hospitalizations for acute MI were identified as either a primary diagnosis of acute MI (ICD-9-CM codes 410.XX) or a primary diagnosis of a complication of an acute MI (ICD-9-CM codes 785.51, 785.59, 429.5, 429.6, and 429.71), with a secondary diagnosis of acute MI. Outpatient pharmacy claims only were used to document new statin prescription. This was attributed only to patients who did not have a pharmacy claim for a statin in the 1-year period before the index test.
We applied propensity scoring to match each patient from the CCTA group with a patient from the SE group in a one-to-one manner. Logistic regression was performed to estimate the propensity scores, with group identification (0 = CCTA; 1 = SE) as the dependent variable and age, gender, geographic location (US census region) where index test was ordered/billed, baseline co-morbidity characteristics (diabetes, hypertension, high cholesterol, statin use, and ischemic heart disease), inpatient status on index encounter, and stress test within previous 6 months as covariates. We obtained from the logistic regression the predicted probability of patients who underwent CCTA as the propensity score and applied stratification matching to match patients from both cohorts by the propensity scores without replacement. We were able to match a majority of the CCTA cohort patients with the SE cohort patients at the 5-digit propensity score resolution. For all remaining unmatched patients who underwent CCTA, we adaptively found their closest matches from the SE cohort at the coarser (<5 digits) propensity score resolution. Multivariable logistic regression analyses were used to examine the relation between the CCTA and SE groups and subsequent outcomes at 3 years, adjusting for potential confounders, which included all covariates described in determination of the propensity score. The independent variables in these analyses were the index tests (CCTA or SE) and the key dependent variables were indicators of receipt of cardiac catheterization, future noninvasive cardiac test (exercise ECG, SE, myocardial perfusion imaging, CCTA), return visit, pharmacy claim for statin, percutaneous coronary intervention, coronary artery bypass graft surgery, or hospitalization for acute MI.
All hypothesis tests were performed on a 2-sided basis with an α of 0.05. The lowest p value reported was <0.0001. Statistical analyses were performed using SAS, version 9.1.3, for data extraction and management.
The cohort consisted of 18,621 unique patients who were seen in the ED at least once from 2011 through 2014 with a primary diagnosis of chest pain and underwent either CCTA (1,908) or SE (16,713) as a first noninvasive imaging test within a 72-hour window. The average age of patients was 49 years and 54% were women. All patients were followed for 3 years from the date of the index encounter. Men were more likely to receive CCTA and women more likely to receive SE ( Table 1 ).
| Variable | Stress echo (unmatched) | Stress echo (matched) | CCTA | P (unmatched) | P (matched) |
|---|---|---|---|---|---|
| n= 16,713 | n= 1,908 | n= 1,908 | |||
| 0.03 | 0.11 | ||||
| Female | 8,992 (53.8%) | 1,042 (54.6%) | 994 (52.1%) | ||
| Male | 7,721 (46.2%) | 866 (45.4%) | 914 (47.9%) | ||
| Age (mean years) | 48.6 | 48.7 | 47.4 | <0.0001 | <0.0001 |
| Region | <0.0001 | <0.0001 | |||
| Northeast | 2,624 (15.7%) | 296 (15.5%) | 340 (17.8%) | ||
| North Central | 7,504 (44.9%) | 747 (39.2%) | 507 (26.6%) | ||
| South | 4,195 (25.1%) | 750 (39.3%) | 947 (49.6%) | ||
| West | 1,588 (9.5%) | 115 (6.0%) | 94 (4.9%) | ||
| Diabetes mellitus | 2,790 (16.7%) | 309 (16.2%) | 315 (16.5%) | 0.84 | 0.79 |
| Hypertension | 7,582 (45.4%) | 944 (49.5%) | 918 (48.1%) | 0.02 | 0.40 |
| High cholesterol | 6,926 (41.4%) | 798 (41.8%) | 831 (43.6%) | 0.08 | 0.28 |
| Statin use | 3,069 (18.4%) | 432 (22.6%) | 371 (19.4%) | 0.26 | 0.02 |
| Ischemic heart disease | 418 (2.5%) | 70 (3.7%) | 60 (3.1%) | 0.09 | 0.37 |
| Inpatient status | 1,272 (7.6%) | 172 (9.1%) | 199 (10.4%) | <0.0001 | 0.14 |
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
