Tsai M-H, Hsu C-Y, Lin M-Y, Yen M-F, Chen H-H, Chiu Y-H, Hwang S-J: Incidence, Prevalence, and Duration of Chronic Kidney Disease in Taiwan: Results from a Community-Based Screening Program of 106,094 Individuals. Nephron 10.1159/000491708
The rate of progression of CKD from one KDIGO defined category (”stage”) to subsequent “stages” (called “dwell time”(DT)) is commonly variable, pending in large part on the specific disease characteristics of the patient population examined (e.g. slow in most patients with ADPKD and often rapid in crescentic glomerulonephritis). Few epidemiological studies have attempted to address this feature of CKD using large data-sets and population cohorts.
Tsai and co-workers examined the “dwell time” in a Taiwanese adult population of CKD Category 3 – 5 (defined by eGFR < 60 ml/min/1.73m2 by the CKD-EPI eGFR equation, without dialysis) over 10 years (from 1999-2009). Dipstick proteinuria was also evaluated. The “dwell time” was represented by the ratio of prevalence to incidence of CKD at various intervals of time for the categories of CKD examined. A short DT was equal to: 1) Premature death; 2) Starting dialysis for ESRD or an aberrant increase in CKD incidence. A total of 106,964 participants were examined (average age 47 years). The overall prevalence of CKD (any category) in this cohort was 15.4 %; 9.6 % in category 3 – 5 CKD, 60 % of whom were women and 5 % diabetic. The overall incidence of CKD category 3 – 5 was 16.89/1000 patients years. Except for diabetes, the cause of CKD was not specified in any patient.
The overall DT for CKD 3 – 5 was 5.35 years (95 % CI = 5.12-5.57). The calculated value for DT was shorter in younger men than in older women and in those with diabetes and metabolic syndrome. The absence of disease diagnosis and a more quantitative approach to the role of proteinuria in determining DT are major weakness of this study. The data do provide some gross descriptive data of progression of CKD but much more “granularity” of the data will be required to translate the findings into meaningful actions to impact the rates of progression and to prolong the DT.