Serum 25-hydroxyvitamin D is associated with incident peripheral artery disease among white and black adults in the ARIC study cohort.

BACKGROUND AND AIMS: Low 25-hydroxyvitamin D [25(OH)D] concentrations have been associated with peripheral artery disease (PAD). Prevalence of low 25(OH)D and PAD differ between whites and blacks. However, these associations have not been studied prospectively or in a population based cohort. We tested the hypothesis that low 25(OH)D is associated with greater risk of incident PAD in white and black adults. METHODS: 25(OH)D was measured in serum collected at ARIC visit 2 (1990-1992). We followed 11,789 ARIC participants free of PAD at visit 2 through 2011 for incident PAD events. 25(OH)D (ng/mL) was categorized as deficient (<20), insufficient (20 to <30) or sufficient (≥30). PAD was defined by an ankle brachial index (ABI) of <0.9 at ARIC visits 3 or 4 or a hospital diagnosis with an ICD-9 code indicating PAD during follow-up. Analysis used multivariable-adjusted Cox proportional hazards regressions. RESULTS: Over a mean follow-up of 17.1 years, 1250 incident PAD events were identified. 22% of whites and 61% of blacks were 25(OH)D deficient. After adjustment for demographic characteristics, the hazard ratio (95% CI) of PAD in participants with deficient versus sufficient 25(OH)D was 1.49 (1.26, 1.76). Inclusion of BMI, physical activity, and smoking status attenuated the association [1.25 (1.06, 1.48)]. The association between 25(OH)D and PAD was qualitatively stronger in blacks (p for interaction = 0.20). CONCLUSIONS: Deficient 25(OH)D was associated with increased risk of PAD in black and white participants. Whether treatment of low vitamin D through supplementation or modest sunlight exposure prevents PAD is unknown.

The role of nutrition and body composition in peripheral arterial disease.

Peripheral arterial disease (PAD) has not been as extensively investigated as other cardiovascular diseases. However, the available data suggest that nutrition-based treatment strategies have the potential to reduce the cost-economic burden of PAD substantially. Abdominal obesity is associated with PAD and prospective and cross-sectional studies have shown that a low dietary intake of folate and reduced synthesis of vitamin D are associated with an increased risk of PAD and severe walking impairment in patients who have the disease. However, dietary patterns that are associated with decreased cardiovascular risk might protect against PAD. A small number of clinical trials have provided evidence that increased intakes of niacin and insoluble fiber might be associated with decreased levels of LDL cholesterol and thrombogenic biomarkers, as well as increased serum levels of HDL cholesterol in patients with PAD. However, little evidence that antioxidants, vitamins B(6) and B(12), or essential fatty acid supplements improve clinical outcomes in these patients exists. Overall, data on the effects of nutrition, body composition, and nutritional supplementation on the risk, progression, and prognosis of PAD are scarce. Further research into these areas is required to allow the development of evidence-based nutritional guidelines for the prevention and treatment of the disease.

Effect of niacin ER/lovastatin on claudication symptoms in patients with peripheral artery disease.

In patients with peripheral artery disease (PAD), statins may improve the symptoms of claudication. The Intermittent Claudication Proof of Principle (ICPOP) study tested the hypothesis that the combination of extended release niacin plus lovastatin would improve exercise performance in patients with PAD and claudication compared with a diet intervention. A phase 3 double-blind, parallel-group, multi-center, 28-week multi-national study evaluated subjects with a history of claudication who had an ankle-brachial index (ABI) < or = 0.90, a reproducible peak treadmill walking time (PWT) of 1-20 minutes, and a low-density lipoprotein (LDL)-cholesterol level < 160 mg/dl (< 4.1 mmol/l). Subjects were randomly assigned to low-dose niacin 1000 mg plus lovastatin 40 mg (low niacin-statin), high-dose niacin 2000 mg plus lovastatin 40 mg (high niacin-statin), or diet intervention (diet). The co-primary efficacy endpoint of percent change in PWT and claudication onset time (COT) at 28 weeks was assessed using a graded treadmill protocol. At completion, 385 subjects were analyzed for safety and 370 subjects were analyzed for efficacy. The primary efficacy analysis showed no statistical significance for overall treatment effect at week 28 for the co-primary endpoint of PWT and COT. The PWT component of the primary endpoint increased 26.5% on diet, 37.8% on high niacin-statin (p = 0.137) and 38.6% on low niacin-statin (p = 0.096). Flushing as the most common event leading to discontinuation and treatment was associated with increases in liver enzymes, fasting blood glucose concentration and a decrease in platelet count.

Development of a multicenter peripheral arterial interventional database: the PVD-QI2.

BACKGROUND: The number of peripheral vascular intervention (PVI) procedures performed is steadily increasing in the United States. PVD-QI 2 is a prospective, multicenter observational study designed to improve the quality of care for patients undergoing PVI and to better understand the effectiveness and appropriateness of PVI in improving outcomes of peripheral arterial disease. The registry aims to elucidate which comorbid conditions and procedure-related variables are associated with beneficial or adverse outcomes after vascular interventions. METHODS: Five centers are currently prospectively collecting data on consecutive PVIs performed at their institutions and will include patients with both claudication and critical limb ischemia. A common data collection form and a standard set of definitions were developed during several planning meetings. Information on patient demographics, clinical history, comorbid conditions, treatment approaches, and in hospital outcomes are being collected. Patients will be followed up at 30 days, 6 months, and 1 year after each procedure to identify recurrent vascular events, medication use, lifestyle modifications (regular exercise, dietary modification), self-reported walking scores, and mortality. Data validity will be assured through review of data form accuracy by a trained nurse, by automatic database diagnostic routines, and by site visits that include review of angiography suite logs and randomly selected charts. CONCLUSIONS: The development of a quality-controlled PVI registry requires the commitment and collaboration of clinician-investigators and hospital systems devoted to understanding factors that contribute to quality outcomes. Central to achievement of this goal is the creation of a careful diagnostic and data quality assessment system. This registry will provide important clinical insights into patient demographic and clinical characteristics, procedural characteristics, and current practice patterns that foster or impede achievement of long-term quality-based clinical outcomes for patients with peripheral arterial disease.