Prevalence of anemia.

The percentages reflect the prevalence of anemia, survey weighted to the US population. The analysis by stage of CKD was limited to subjects with CKD as defined in the Methods section (N = 2,125); data for anemia were missing for a total of 7 CKD patients (<1%), all in stages 1–3. Prevalence of anemia in subjects without CKD was determined in 9,269 subjects with non-missing data on anemia status.