Recent Trends in the Prevalence of Chronic Kidney Disease

Not the Same Old Song

Raymond K. Hsu; Neil R. Powe

Disclosures

Curr Opin Nephrol Hypertens. 2017;26(3):187-196. 

In This Article

Update in Diabetic Kidney Disease Prevalence in the United States

In a second well publicized study in 2016, Afkarian et al.[18] similarly used NHANES data (from 1988 to 2014) to specifically address the temporal trend in prevalence of diabetic kidney disease (DKD), defined as having albuminuria (urine ACR ≥ 30 mg/g) and/or eGFR less than 60 ml/min/1.73 m2 (estimated with CKD-EPI creatinine equation[11]) among individuals with diabetes. In this study, diabetes status was defined as use of glucose-lowering medications or a laboratory-measured HbA1c level of at least 6.5%; the authors did not use self-reported history of diabetes due to concern that secular changes in diabetes screening and diagnosis could lead to biased estimates of the overall diabetic population (the denominator of interest). Using this strict definition of diabetes, Afkarian et al. found that the prevalence of diabetes in the United States increased from 6% in 1988–1994 to 9.8% in 2009–2014. There was a higher proportion of diabetic patients who self-identified as Mexican-American over time (from 6.6% in 1988–1994 to 10.4% in 2009–2014).

Among US adults with diabetes, the overall crude prevalence of DKD (albuminuria and/or eGFR < 60 ml/min/1.73 m2) did not change significantly during the study period (from 28.4% in 1988–1994 to 26.2% in 2009–2014).[18] These prevalence rates took into account persistence of abnormal eGFR and ACR measurements rather than relying on one-time measurements (a technique that is different from the study by Murphy and other prior NHANES analyses). However, the prevalence of reduced eGFR (<60 ml/min/1.73 m2) increased from 9.2 to 14.1%, whereas the prevalence of albuminuria decreased from 20.8 to 15.9% (Table 1). The decline in albuminuria prevalence among people with diabetes appeared to be largely driven by those younger than 65 years and non-Hispanic whites, as older subgroups and racial-ethnic minority subgroups did not demonstrate a decline in albuminuria prevalence.

The study by Afkarian et al.[18] updated the same research group's previous study on DKD prevalence in the United States[29] by extending analyses through 2014 and importantly illustrated less-favorable trends for albuminuria in older and racial-ethnic minority subgroups. Notably, the authors directly showed that although mean BP, HbA1c, and cholesterol levels decreased over time in the overall US diabetic population and in all racial-ethnic subgroups, the achieved levels of BP, HbA1c, and LDL cholesterol were higher (i.e., less optimal) in racial-ethnic minorities (Fig. 2). The proportion of adults with diabetes taking glucose-lowering medications, renin–angiotensin–aldsterone system (RAAS) inhibitors, and statins increased over time, but blacks and Mexican-Americans were less likely than non-Hispanic whites to be taking these medications throughout all periods (Fig. 2). Therefore, it is postulated that the decline in albuminuria among younger and white subgroups may be attributable to higher rates of prescribed diabetes therapies, whereas less-frequent use of these proven therapies may underlie the less-favorable trends in albuminuria in blacks and Mexican-Americans.

Figure 2.

Medication use and trends in clinical targets for the adult US population with diabetes by race/ethnicity. (a) There has been progressively higher use of glucose-lowering medications, rennin–angiotensin–aldosterone system inhibitors, and statins among adults with diabetes, but usage is lower in blacks and Mexican-Americans compared with whites across all National Health and Nutrition Examination Surveys periods. (b) Hemoglobin A1c, SBP, and LDL cholesterol levels have decreased over time among adults with diabetes; blacks and Mexican-Americans have higher hemoglobin A1c and LDL cholesterol levels than whites in the most recent time periods. Error bars indicate 95% confidence intervals; NHANES, National Health and Nutrition Examination Surveys. Participants of all races and ethnicities were included in the analyses, and estimates were reported for non-Hispanic white, non-Hispanic black, and Mexican-American race/ethnicity only. Reproduced from [18].

It is not clear why the prevalence of reduced eGFR less than 60 ml/min/1.73 m2 among people with diabetes increased over time[18] (a finding in contrast with the stable prevalence of eGFR < 60 ml/min/1.73 m2 in the overall US population[10]). The authors postulated that although an aging population is unlikely the reason (as this trend persisted after adjustment for demographics), it is possible that hemodynamic effects of RAAS inhibitors and improved BP control could have contributed to lower eGFR.

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