NEW ORLEANS—Chronic kidney disease (CKD), defined as a glomerular filtration rate of 60 mL/min/1.73 m2 or below, is an independent predictor of death in patients with peripheral vascular disease (PVD), researchers reported at the 60th Annual Scientific Session of the American College of Cardiology.

The study, by researchers at West Virginia University in Charleston led by Aravinda Nanjundappa, MD, and Molly John, MD, also found no association between obesity and mortality in PVD patients. Study findings were presented by Ashwin Bhirud, a fourth-year medical student at West Virginia.

“The findings suggest that it may be important to achieve better control of kidney disease in PVD patients in order to reduce PVD-associated mortality,” Bhirud said.

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The investigators reviewed the medical records of 303 consecutive patients who underwent either endovascular or surgical procedures to treat PVD at a Charleston-area medical center during a recent two-year period.

Despite the availability of interventions aimed at decreasing risk factors for atherosclerosis, PVD remains a major burden in the primary care population, Bhirud pointed out. The estimated prevalence of PVD in the general population is about 6.9%. The 10-year all-cause mortality rate is 75% in severely symptomatic patients and 45% in asymptomatic patients. The main cause of mortality is stroke and myocardial infarction.

A recent meta-analysis found that CKD and an estimated GFR rate of 60 or below are associated with an increased risk for all-cause mortality, cardiovascular disease (CVD), and progression to renal failure even after adjustment for co-morbidities and other traditional risk factors.

In addition, obesity in PVD patients has been shown to be associated with an increased risk of CVD, he said.  In one study, PVD patients who were obese (body mass index of 30 kg/m2 or higher) had a nearly 2.5-fold increased risk of cardiovascular events.

Although obesity correlates with increased CVD risk, some studies have actually reported an obesity paradox in which overweight or obese patients have better outcomes than non-overweight or obese patients. Thus, the impact of both CKD and obesity on mortality in PVD patients is unclear, Bhirud said.

In the present study, 174 (57.4%) patients had normal GFR levels (above 60) and 129 (42.6%) had low GFR levels (60 or below), denoting stage 3 or worse CKD.

Results showed significant differences in all-cause mortality between patients with normal GFR levels and patients with low GFR levels for all three time periods studied. The 30-day mortality rates were 1.1% and 8.5% in the two groups, respectively. The one-year mortality rates were 11.5% and 26.4%, and the three-year mortality rates were 21.8% and 43.4%.

In the study population, 217 patients were obese and 86 were not. The percentages of patients who died at 30 days, one year, and three years were the same in obese and non-obese patients.

“Our finding that a low GFR independently predicts both short- and long-term mortality suggests that perhaps better control of stage 1 and 2 CKD in PVD patients can help slow progression to stage 3 or 4 CKD, at which time patients have an increased risk of death,” Bhirud said. “Aggressive strategy to reduce the risk factors of peripheral arterial disease and CKD may improve patient survival.