Carotid Artery Stenosis: Rates of Surgery

March 13, 2017
Veronica Hackethal, MD

Does clinician reimbursement structure (fee-for-service vs salary-based) affect type of care for patients with carotid artery stenosis?

Patients with carotid artery stenosis who receive care in a fee-for-service system are significantly more likely to undergo surgical intervention for their condition than patients in a salary-based system, according to a study published online in JAMA Surgery.1

“[T]he current study demonstrates variation in health care use by clinician reimbursement type in a synchronous national cohort. The finding that the odds of intervention are higher among patients in the purchased care group compared with those in the direct care group suggests that such variation may be associated with clinician compensation structure,” wrote first author Louis Nguyen, MD, MBA, MPH, of Brigham and Women’s Hospital (Boston, MA) and colleagues.

Carotid artery stenosis represents a major risk factor for ischemic stroke. It can be managed through reducing risk factors and medical management (antiplatelet therapy, cholesterol-lowering agents, control of hypertension), or surgical procedures (carotid endarterectomy or carotid artery stenting).  Medical management is recommended for all patients with carotid artery stenosis. Carotid endarterectomy is recommended for symptomatic patients with 50-99% stenosis, and asymptomatic patients with 60-99% stenosis and a good risk profile. Stenting is usually reserved for patients at high surgical risk.2

Recent studies suggesting relatively small benefit for surgical over medical management have contributed to debate about whether all asymptomatic patients with carotid artery stenosis should receive medical management, regardless of the amount of stenosis. An important issue in these arguments centers around the financial interests of providers to influence choice of care, particularly in fee-for-service systems where surgical interventions are reimbursed at higher rates than medical management.

To investigate the issue, researchers used data from the Department of Defense Military Health System Data Depository database, which contains data on patients who received care from salaried military physicians or private sector fee-for-service physicians as part of the military’s TRICARE program. The analysis included 10,579 patients diagnosed with carotid artery stenosis between October 2006 and September 2010 (4615 women and 5964 men; mean age, 65.6 years).

Key Results:

• 12.4% of patients (n=1307) underwent endarterectomy or stenting

• Odds of surgical intervention 62% higher in fee-for-service than salary-based systems (odds ratio, 1.629; 95% CI, 1.285-2.063; P<0.001).

• Odds of surgical intervention over nine times higher in symptomatic vs asymptomatic patients (OR, 9.487; 95% CI, 7.611-11.824; P<0.001).

• Odds of stroke significantly higher in the fee-for-service vs salary-based systems:

♦ 30 days: OR, 1.981; 95% CI, 1.544-2.542; P<0.001

♦ 1 year: OR, 1.599; 95% CI, 1.329-1.923; P<0.001

♦ 2 years: OR, 1.486; 95% CI, 1.235-1.788; P<0.001

• Odds of all-cause mortality higher in fee-for-service vs salary-based systems:  

♦ 30 days: OR, 1.976; 95% CI, 0.424-9.203; P=0.39

♦ 1 year: OR, 1.673; 95% CI, 1.165-2.402; P=0.005

♦ 2 years: OR, 1.777; 95% CI, 1.285-2.458; P<0.001

The authors pointed out that symptomatic patients were more likely to receive surgical intervention in the fee-for-service setting, and less likely to receive surgical intervention in the salary-based setting, suggesting undertreatment in the latter.

“The higher rates of intervention for carotid artery stenosis in the fee-for-service setting are consistent with physician-induced demand for this disease in this patient population. However, the treatment of symptomatic patients in this cohort suggests that the clinicians in the fee-for-service system are appropriately aggressive toward carotid artery stenosis,” they wrote.

However, they noted that this study alone cannot establish whether higher intervention rates in the fee-for-service system compared to salaried system is due to overtreatment in the fee-for-service setting or undertreatment in the salary-based setting.

“Although it is difficult to capture fully the factors that motivate patients and clinicians, with respect to the management of carotid stenosis by surgeons and other interventionists, our results do appear to support the conclusion that physician-induced demand may be at work. Given these findings, the health care community should focus on ways to detect the potential for physician-induced demand and craft policies that will align the incentives of patients, clinicians, and society,” they concluded.

Take-home Points

• A study using the military health system database found patients with carotid artery stenosis who receive care in a fee-for-service system are significantly more likely to undergo surgical intervention for their condition than patients in a salary-based system.

• Odds of death and all-cause mortality are higher in fee-for-service vs salary-based system.

• Odds of surgical intervention were nine times higher in symptomatic vs asymptomatic patients.

• Results suggest physician-induced demand may be involved in higher rates of surgical intervention for carotid artery stenosis in the fee-for-service setting.

The authors report no conflicts of interest.

References:

1. Nguyen LL, et al. Provider-induced demand in the treatment of carotid artery stenosis: variation in treatment decisions between private sector fee-for-service vs salary-based military physicians. JAMA Surg. 2017 Mar 1.

2. Brott TG, et al. 2011 ASA/ACCF/AHA/AANN/AANS/ACR/ASNR/CNS/SAIP/SCAI/SIR/SNIS/SVM/SVS guideline on the management of patients with extracranial carotid and vertebral artery disease: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines, and the American Stroke Association, American Association of Neuroscience Nurses, American Association of Neurological Surgeons, American College of Radiology, American Society of Neuroradiology, Congress of Neurological Surgeons, Society of Atherosclerosis Imaging and Prevention, Society for Cardiovascular Angiography and Interventions, Society of Interventional Radiology, Society of NeuroInterventional Surgery, Society for Vascular Medicine, and Society for Vascular Surgery. J Am Coll Cardiol. 2011;57(8):e16-e94.

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