Epidemiology of Chronic Kidney Disease Among Normotensives

Abstract

Among adults in the United States, 1 in 4 has hypertension and 1 in 8 has chronic kidney disease (CKD). Although the relationship between hypertension and CKD has been recognized for several hundred years, the prevalence of CKD among patients with normal blood pressure has not been assessed in randomly sampled populations. Crews et al1 in this issue of Hypertension are the first to report such estimates: 13.4% of people who have normal blood pressure have CKD. Among those with prehypertension, the prevalence is 17.3%; among those with undiagnosed hypertension, the prevalence is 22.0%; and among those with diagnosed hypertension, the prevalence is 27.4%. The magnitude of these CKD prevalence estimates is astounding and may even be misleading unless placed in appropriate context. The awareness of CKD diagnosis was dismal: <10% of people were aware of CKD regardless of hypertension category. A thorough analysis of the definition of CKD is necessary to understand how the varying definitions of CKD may have influenced both the prevalence and awareness estimates. The prevalence estimates may be inflated because of CKD that is so mild that it may not be considered a disease at all. For example, examination of the Figure (derived from Table 3 of the article) shows that if one considers the prevalence of more severe CKD defined as macroalbuminuria or estimated glomerular filtration rate (GFR) <45 mL/min per 1.73 m2, then the prevalence estimates fall dramatically. These stricter definitions of CKD yield the following prevalence estimates of CKD: normal blood pressure 0.5%; prehypertension 1.0%; undiagnosed hypertension 2.0%; and <5.0% prevalence of CKD among those with diagnosed hypertension. These prevalence estimates are much lower than those obtained with the more sensitive definition that is typically used to define CKD. Thus, the prevalence estimates of CKD may be driven up …