The CKD Health Policy Model is a microsimulation model for CKD progression that simulates the history of CKD for adults aged 30 to 90 years. All adults used in the model had been participants in the National Health and Nutrition Examination Survey (NHANES) from 1999 through 2010. The model placed participants into one of seven different categories: no CKD, Stages 1-5, and death. CKD stage was determined by eGFR and the presence of albuminuria using the NKF-KDOQI guidelines. The model was used to project the prevalence, lifetime incidence, and residual incidence of CKD through the year 2030.
Residual lifetime risk of CKD is defined as the probability of reaching any stage of CKD (stages 1-5) in individuals who do not have CKD at the start of the simulation. In the simulation, persons must progress through stage 3a before reaching stage 3b, through stages 3a and 3b before reaching stage 4, and through stages 3a, 3b, and 4 before reaching stage 5. However, it is possible to reach stage 3a or higher without going through stages 1 and 2 if a person never has elevated albuminuria. The unconditional lifetime incidence is defined as the probability of starting with or progressing to any stage of CKD. This calculation accounts for both those that have CKD at the start of the simulation, as well as the residual lifetime incidence for those who do not have CKD at the start.
The NHANES is currently conducted every 2 years by the National Center for Health Statistics to examine disease prevalence and trends over time in different cross-sectional representative samples of noninstitutionalized U.S. civilian residents. The survey consists of a standardized in-home interview and a physical examination and blood and urine collection at a mobile examination center (MEC). Here, we examined data from the 1999-2000, 2001-2002, 2003-2004, 2005-2006, 2007-2008, and 2009-2010 NHANES. eGFR was calculated according to the modified MDRD study formula for calibrated creatinine (Levey et al., 2005; Levey et al., 2006). Serum creatinine was calibrated for 1999-2000 and 2005-2006 participants; no correction was required for calibrated serum creatinine in participants in the 2001-2002, 2003-2004, 2007-2008, and 2009-2010 (Selvin et al., 2007). Albuminuria was defined by urinary albumin-to-creatinine ratios of 30-299 mg/g (microalbuminuria) and >300 mg/g (macroalbuminuria); pregnant women were excluded. For comparisons across the 12-year period 1999-2010, albuminuria was corrected in 1999-2006 to account for differences in the instrumentation and method for urine creatinine starting in 2007.
This indicator is based upon analysis in published literature: Hoerger TJ, Simpson SA, Yarnoff BO, et al. The future burden of CKD in the United States: a simulation model for the CDC CKD Initiative. Am J Kidney Dis