Cardiorenal risk as a new frontier of nephrology: research needs and areas for intervention.

Understanding and modifying the causes of the high cardiovascular morbidity and mortality associated with renal disease is the greatest challenge faced by renal physicians. About one person in 20 has a serum creatinine level above normal (> or =1.5 mg/dl in males and > or =1.4 mg/dl in females), signifying mild kidney disease. People with hypertension, hyperlipidaemia, and/or diabetes (approximately 350000 people per million in the general population) have the highest risk of renal failure. Anaemia, extracellular volume expansion, increased angiotensin II and aldosterone levels, high calcium-phosphate product, inflammation, hyperhomocysteinaemia, and impaired nitric oxide synthesis all amplify the risk of cardiovascular disease in patients with renal failure. These factors may adversely affect the cardiovascular system by influencing the generation of reactive oxygen species, thus contributing to high oxidative stress. Further research into optimal follow-up of patients with mild renal insufficiency is needed. Identification of 'problematic' and/or treatment-resistant patients should be a primary goal. Greater understanding of the genetic and environmental precursors of diseases associated with renal insufficiency would also be beneficial, particularly for younger patients. Observational studies aimed at linking these risk factors to well-defined and measured renal and cardiovascular outcomes should increase knowledge of renal disease progression and cardiovascular risk in these populations.