Chronic kidney disease: whom to screen and how to treat, part 1: definition, epidemiology, and laboratory testing.

Chronic kidney disease has become a major public health problem due to its high prevalence, its exorbitant cost, and large reductions in life expectancy and quality of life of affected people. Seventy percent of cases of end-stage renal disease are due to diabetes and hypertension, conditions which are usually managed by primary care providers. Other risk factors are cardiovascular disease, obesity, smoking, family history of kidney disease, and age greater than 55 years. Patients with these risk factors should be evaluated for the presence of chronic kidney disease during their primary care visits, because effective treatments for slowing progression are available, particularly if instituted early. Chronic kidney disease can be diagnosed by simple blood and urine tests, as recommended in guidelines issued by the National Kidney Foundation. This article begins with a case vignette, representing a common clinical scenario from a general internist's practice. We then review the definition and classification of chronic kidney disease, the epidemiology, etiology, and interconnections with cardiovascular disease. We discuss the guidelines for screening and laboratory testing, as well as the limitations of current assessment tools. A subsequent article will review evidence-based management of chronic kidney disease.