Study Shows Socioeconomic Disparities in Treatment of CLI Patients

January 28, 2011—The Society for Vascular Surgery announced that Louis L. Nguyen, MD, et al have published a study in the Journal of Vascular Surgery analyzing the impact of socioeconomic status and access to high-volume hospitals on the rate of amputation versus revascularization (2011;53:307–315). The investigators hypothesized that disparities in limb salvage procedures may be driven by socioeconomic factors and sought to identify specific status factors that may be associated with major amputation in the setting of critical limb ischemia (CLI).

As detailed in the Journal of Vascular Surgery, the investigators queried the Nationwide Inpatient Sample from 2003 to 2007 for discharges containing lower extremity revascularization or major amputation and chronic CLI (N = 958,120). The Elixhauser method was used to adjust for comorbidities. Significant predictors in bivariate logistic regression were entered into a multivariate logistic regression for the dependent variable of amputation versus lower extremity revascularization.

The investigators reported that overall, 24.2% of CLI patients underwent amputation. Significant differences were seen between both groups in bivariate and multivariate analysis of socioeconomic status factors, including race, income, and insurance status. The investigators found that lower-income patients were more likely to be treated at institutions that perform a low volume of lower extremity revascularization (odds ratio [OR], 1.74; P < .001). Patients at higher-volume centers (OR, 15.16; P < .001) admitted electively (OR, 2.19; P < .001) and evaluated with diagnostic imaging (OR, 10.63; P < .001) were more likely to receive lower extremity revascularization.

After controlling for comorbidities, the investigators concluded that minority patients, those with lower socioeconomic status, and patients with Medicaid were more likely receive amputation for CLI in low-volume hospitals and that addressing socioeconomic status and hospital factors may reduce amputation rates for CLI.

According to the Society for Vascular Surgery, the data showed that several indicators of low socioeconomic status were clustered by demographic group. Compared with white patients, Native Americans were the most likely to have income in the lowest quartile. Similar lower median income was seen for African American and Hispanic patients. Nonwhites were more likely to be on Medicaid and had lower income than patients with Medicare.

“Minority patients tend to have more comorbidities, including diabetes, peripheral artery disease, and renal failure, which influence treatment options as they are more likely to receive care at low-volume and potentially under-resourced hospitals,” commented Dr. Nguyen. “These factors, independently and in combination, are associated with a greater likelihood of major amputation. This outcome profoundly impacts the function of CLI patients and their quality of life. Our data are similar to other reports that patients with CLI who present to higher-volume hospitals are more likely to undergo a limb salvage procedure.”

The investigators stated that higher-volume hospitals may have more fellowship-trained vascular specialists, established protocols for perioperative care of patients with CLI, and greater access to angiography facilities. Patients who did not have primary payer insurance also had lower income than those with Medicare and were more likely to be minorities. Demographic trends showed that there were factors associated with amputation versus revascularization, which also included older age and male gender.

Compared to patients with the highest income, patients in the lower three income quartiles were at 11% to 34% higher odds of undergoing major amputation. Private insurance remained inversely associated with major amputation, and patients with Medicaid were at slightly increased odds of major amputation than those with Medicare.

In comparison to patients at the highest-volume centers, patients at the lowest-volume centers had 15.2 times higher odds of undergoing major amputation. Patients in the second quartile were also at significantly increased odds of undergoing major amputation, and those at hospitals in the third quartile were at 77% higher odds of undergoing major amputation compared to those at the highest volume.

“Our findings suggest there are gaps in access to care despite controlling for hospital level factors and procedural volume,” added Dr. Nguyen. “Addressing socioeconomic status, hospital factors, and the inverse relationship between lower extremity revascularization procedure volume and risk of major amputation for CLI highlights potential solutions for disparities related to hospital level factors. Also, increasing state and local funding to facilities that provide care to patients at high risk for major amputation may improve professional resources.”

Dr. Nguyen added that further analysis of datasets that contain information on referral patterns and utilization of outpatient health care could guide potential interventions that target patients at high risk for peripheral artery disease and major amputation. He noted that this information could also lead the way for implementing screening protocols focused on risk factor modification and appropriate early vascular surgery referral pathways.

“Given the highly positive impact of preoperative angiography on the likelihood of undergoing a lower extremity revascularization procedure, studying the factors influencing the clinical decision to evaluate revascularization options may illustrate reasons for the less frequent use of angiography in certain patient populations and help to more widely implement standard diagnostic protocols,” concluded Dr. Nguyen. “Further exploration of these potential mechanisms of disparities both at the patient and the hospital levels may improve limb salvage for the vulnerable population.”