Is chronic kidney disease a cardiovascular disease risk factor?

Cardiovascular disease (CVD) is prevalent in patients with chronic kidney disease (CKD) and may account for 50% of all deaths. The recent Dialysis Outcomes Quality Initiative (DOQI) publication on the evaluation, classification, and stratification of CKD states that a reduced glomerular filtration rate (GFR) identifies individuals at greater risk for CVD and death. This risk is the result of traditional and nontraditional CVD risk factors. However, the relative contribution of these risk factors in the CKD population remains uncertain. Recently interest in kidney disease (reduced GFR) as an independent nontraditional risk factor for CVD has come to the forefront. Studies examining this potential link have included community-based cohort studies, studies in patients with extensive comorbidity, and reports in kidney transplant recipients. Herein, results from these studies are reviewed. The difference between an independent CVD risk factor and a causal CVD risk factor is discussed, with particular emphasis on the temporal association between exposure (GFR) and outcome (CVD and CVD death).