Kidney Disease Common in Undiagnosed and Prediabetes

Kidney Disease Common in Undiagnosed and Prediabetes

   By Crystal Phend, Senior Staff Writer, MedPage Today
March 26, 2010


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* Explain to interested patients that guidelines recommend screening for chronic kidney disease for individuals with diabetes and those with hypertension, but not for those with prediabetes.


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Individuals with undiagnosed diabetes and prediabetes also have a high incidence of unrecognized chronic kidney disease, researchers found.

More than 40% of people with undiagnosed diabetes had chronic kidney disease, based on albuminuria or reduced estimated glomerular filtration rate (eGFR) -- just as many as in those with diagnosed diabetes, according to Laura C. Plantinga, ScM, of San Francisco General Hospital and University of California San Francisco, and colleagues.

In their analysis of National Health and Nutrition Examination Survey data, prediabetes was associated with a 70% higher prevalence of chronic kidney disease than in the nondiabetic population (17.7% versus 10.6%).

Based on these results, an estimated 13 million American adults with undiagnosed or prediabetes have chronic kidney disease, they wrote in the Clinical Journal of the American Society of Nephrology.

But all these cases are likely going unrecognized and untreated in the absence of another concurrent risk factor, such as hypertension, Plantinga's group warned, especially since guidelines recommend annual kidney disease screening only for those with diagnosed diabetes.

Screening guidelines should change to include prediabetes, they recommended.

While agreeing that this shift is warranted, Gary C. Curhan, MD, ScD, of Channing Laboratory at Brigham and Women's Hospital and the Harvard School of Public Health in Boston, cautioned in an accompanying editorial that definitions for prediabetes and chronic kidney disease might need to be re-examined.

He also warned that screening isn't enough.

"Pharmacologic intervention with angiotensin-converting enzyme inhibitors or angiotensin receptor blockers should be used to slow progression," he wrote in the editorial, noting low rates of use even in those with diagnosed diabetes.

Plantinga's group examined the nationally-representative NHANES data for 1999 through 2006, which included 8,188 adults over age 20 with complete fasting plasma glucose, serum creatinine, and urinary albumin-to-creatinine ratio measurements.

Overall, 39.6% of the 826 individuals who self-reported physician-diagnosed diabetes had chronic kidney disease, defined by an eGFR of 15 to 59 ml/min per 1.73 m2 or an albumin-creatinine ratio over 30 mg/g.

By comparison, 41.7% met the same chronic kidney disease criteria among the 299 survey respondents who had a fasting plasma over 126 mg/dl but didn't report having been diagnosed with diabetes.

Chronic kidney disease appeared to be just as severe for undiagnosed individuals as well (40.6% at stage 3 or 4 versus 39.0%).

Notably, 56.2% of chronic kidney disease was stage 3 or 4 among those with prediabetes, indicated by a fasting plasma glucose between 100 and 126 mg/dl, and for whom kidney dysfunction was likely unsuspected.

Further adjustment for age, gender, and race or ethnicity dropped the prevalence of chronic kidney disease to 24.2% in undiagnosed diabetics and 32.9% in diagnosed diabetes but had little impact on the prevalence in prediabetes (17.1%) and no diabetes (11.8%).

Different equations to estimate kidney function had only a slight impact on prevalence.

The researchers noted that about 10% of those with undiagnosed diabetes reported no routine site for healthcare, suggesting they are "likely not being followed for any chronic kidney disease risk factors."

But even having insurance and a routine site for healthcare, or having a condition such as hypertension that is known to increase kidney disease risk, wasn't associated with lower chronic kidney disease prevalence among those with known diabetes, they added.

"Thus, greater community awareness of diabetes and its risk factors may be needed to improve detection of both diabetes and subsequent chronic kidney disease among these individuals," they wrote in the journal paper.

Plantinga's group cautioned that their study was limited by lack of data on duration of diabetes, possible misclassification of early-stage, chronic kidney disease because of the limitations of GFR estimation and single spot urine measurements, and progression of kidney disease.

Moreover, the study could not show causality, which Curhan noted in pointing out that higher prevalence of chronic kidney disease may be the result of shared risk factors with diabetes, such as obesity. Body mass index was not factored into the analysis.

The project was supported under a cooperative agreement from the CDC through the Association of American Medical Colleges.

The researchers reported no conflicts of interest.

Curhan reported support from a National Institutes of Health grant but no conflicts of interest.
Primary source: Clinical Journal of the American Society Nephrology
Source reference:
Plantinga LC, et al "Prevalence of chronic kidney disease in US adults with undiagnosed diabetes or prediabetes " Clin J Am Soc Nephrol 2010; 5: 673–82.

Additional source: Clinical Journal of the American Society Nephrology
Source reference:
Curhan GC "Prediabetes, Prehypertension ... is it time for pre-CKD?" Clin J Am Soc Nephrol 2010; 5: 557–59.

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