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Prediabetes a Pathway to Heart and Kidney Disease

Apr 14, 2018
 

Individuals with undiagnosed diabetes, prediabetes found to have high incidence of unrecognized chronic kidney disease.

Before having diabetes, people usually have prediabetes. Even though diabetes has not been diagnosed, high sugar levels in prediabetes can be causing problems throughout the body. One of the main organs that can be damaged is the kidney.

People with prediabetes often have unrecognized chronic kidney disease (CKD), according to new research. In this large study, more than one third of the people with prediabetes were found to have two signs of kidney disease:

  • protein in the urine (called albuminuria). Albuminuria is not normal.
  • reduced estimated glomerular filtration rate (eGFR). This is a measure of how well the kidneys work; the eGFR tells the stage of kidney disease.

In the people with prediabetes, the stage of chronic kidney disease was just as advanced as people with diabetes. Many people with either prediabetes or diabetes were found to have stage 3 or 4 chronic kidney disease. There are 5 stages of chronic kidney disease. When the disease reaches stage 5, the person will need kidney replacement therapy, either transplantation or dialysis.

As reported in The Lancet Diabetes and Endocrinology, online February 28, researchers examined a nationally representative sample of 27,971 adults surveyed in four waves from 1988 to 1994, 1999 to 2004, 2005 to 2010 and 2011 to 2014. They estimated that the number of adults with prediabetes increased from 56.2 million at the start of the study period to 78.5 million by the end and will continue to increase, not just in the U.S. but globally.

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. In the analysis of National Health and Nutrition Examination Survey data, prediabetes was associated with a 70% higher prevalence of chronic kidney disease than in the population without diabetes (17.7% versus 10.6%).  Based on these results, an estimated 13 million American adults with undiagnosed or prediabetes have chronic kidney disease.

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

They examined the nationally representative NHANES data for 1999 through 2006, which included 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 glucose over 126 mg/dl but didn’t report having been diagnosed with diabetes.

Chronic kidney disease appeared to be just as severe for individuals who have not been diagnosed 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 people who were not diagnosed  with diabetes and 32.9% in diagnosed diabetes but had little impact on the prevalence in prediabetes (17.1%) and no diabetes (11.8%).

By the end of the study, 37% of people with prediabetes had high blood pressure, 51% had dyslipidemia, 24% smoked, 5% had a reduced glomerular filtration rate, and 8% had elevated levels of urinary albumin.

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.

The 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.

Practice Pearls:

  • Screening guidelines should change to include prediabetes.
  • Definitions for prediabetes and chronic kidney disease need to be re-examined.
  • “Pharmacologic intervention with angiotensin-converting enzyme inhibitors or angiotensin receptor blockers should be used to slow progression of kidney disease.

Reference:

Lancet Diabetes Endocrinol 2018. 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.