The chronic kidney disease epidemic: stepping back and looking forward.

Estimating the prevalence of chronic kidney disease (CKD) is no simple task. The overall prevalence is relatively low but may be higher in select populations that are not accessible to surveys (e.g., certain ethnic groups, the sick or elderly). Moreover, the tests that define CKD lack precision and transportability to healthy populations. During the past decade, it is not clear that CKD has grown substantially. Some epidemiologic factors that are associated with CKD (obesity and diabetes) are increasing, whereas others (uncontrolled hypertension and smoking) are decreasing. Reasons for the discrepancy between a stable CKD population and ongoing ESRD growth remain speculative. There is evidence that ESRD rates may be stabilizing and that efforts to reduce progression in high-risk groups may be starting to show benefit. Expanding the definition of CKD and increasing detection may be required to reduce overall ESRD prevalence. One concern is that many of the well-defined high-risk patient groups (diabetes and black) are still undertreated. Increasing the investigation and treatment of low-risk patients may not be the answer. Clinical inertia (failure to initiate or change therapy) may be a more significant and modifiable barrier toward reducing ESRD, and this deserves increased attention. Furthermore, reducing CKD prevalence will require controlling the precipitating causes. The incremental benefit of detecting CKD in low-risk patients, use of expensive therapies in CKD, or new strategies such as the treatment of prehypertension require solid evidence, not only of the variety that shows benefit (hard end points) but also to whom, when, and at what cost.