Microalbuminuria Screening for Black Patients May Cut Costs

Steven Fox

November 30, 2012

Screening blacks for microalbuminuria helps spot chronic kidney disease (CKD) earlier and may be cost-effective, according to results from a study published in the November 30 issue of the Journal of the American Society of Nephrology.

The study was conducted by Thomas Hoerger, PhD, a health economist at RTI International, Research Triangle Park, North Carolina, and colleagues.

The researchers had previously developed and used a predictive tool they call the CKD Health Policy Model to assess the overall cost-effectiveness of screening for microalbuminuria. Similar to findings regarding screening for and treatment of macroalbuminuria, the researchers' model suggested that screening for microalbuminuria is associated with earlier diagnosis of CKD and is cost-effective in people with diabetes and hypertension.

However, screening black patients presents some different issues, the researchers point out.

Even though blacks have a similar, or even lower, prevalence of CKD compared with other racial groups, once diagnosed with CKD they are significantly more likely to progress to end-stage renal disease (ESRD), the authors note.

The researchers also say that although their previously validated CKD Health Policy Model performs well in predicting the prevalence and cumulative incidence of ESRD in the US population as a whole, the original version does not provide reliable data on the elevated risk kidney disease poses for blacks.

In an effort to address that shortcoming, Dr. Hoerger and colleagues undertook the present study.

"The purpose of this paper is to calibrate the CKD Health Policy Model so that it accurately forecasts the observed higher ESRD rates for African Americans, and to use the calibrated model to estimate the cost-effectiveness of microalbuminuria screening for African Americans and non-African Americans," they write.

They add that the study is the only one they know of that uses a simulation model to assess the variations in CKD progression between blacks and non-blacks.

The earlier model associates how various risk factors such as diabetes, hypertension, and elevated albuminuria affect glomerular filtration rates (GFRs). In this study, the researchers adapted that model to mirror how those risk factors vary by race and then used the recalibrated model to estimate the cost-effectiveness of albuminuria screening, followed by treatment with either angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers.

However, the researchers note, plugging those racial differences into the model still did not fully explain why blacks have much higher lifetime incidences of ESRD, so they decided to tweak the model once again, assuming a 20% increase in the rate of GFR decline in black patients at stage 3 CKD and a 60% increase at stage 4.

Changes Yielded Success

"By incorporating race-specific risk factor prevalence rates and the race-specific multipliers, we were able to closely replicate observed lifetime incidence of ESRD estimated from [US Renal Data System] data while closely matching prevalence of stages 3, 4, and 5 identified in [National Health and Nutrition Examination Survey] data," they write

They note, however, that for blacks, their revised model overestimated the total prevalence of CKD, especially stages 1 and 2.

Even so, the authors say, the models demonstrate that screening blacks for microalbuminuria, in addition to spotting CKD early, also makes financial sense.

Compared with conventional care, screening blacks at 10-year intervals was associated with an incremental cost-effectiveness ratio of $9000 at 10-year intervals, $11,000 at 5-year intervals, $19,000 at 2-year intervals, and $35,000 if screening were done yearly.

Comparable figures for non-blacks were $17,000 for 10-year intervals, $23,000 for 5-year intervals, $44,000 for 2-year intervals, and $81,000 for yearly screenings.

"In summary, these models suggest that screening African Americans for microalbuminuria at either 5- or 10-year intervals is highly cost-effective," they conclude.

The study was supported by funding from the Centers for Disease Control and Prevention. The authors have disclosed no relevant financial relationships.

J Am Soc Nephrol. 2012;23:2035-2041. Abstract