Diabetes Prevalence Data Herald High Rates of Kidney Disease in Years Ahead

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A recently released report on diabetes prevalence underscores the need for determined efforts to contain the burden of diabetes and diabetic complications in the years ahead.

The Centers for Disease Control and Prevention’s (CDC) 2017 National Diabetes Statistic Report highlights the devastating impact of diabetes in the US, with estimates suggesting that 30 million Americans have diabetes and another 70 million meet criteria for prediabetes.

“More than a third of US adults have prediabetes, and the majority don’t know it,” said CDC Director Brenda Fitzgerald, MD. “Now, more than ever, we must step up our efforts to reduce the burden of this serious disease.”

The aging US population and sky-high percentage of Americans with prediabetes mean diabetes-related complications will continue to be a concern moving forward. Based on a US Renal Data System report, more than 52,000 Americans developed ESRD with diabetes as the primary cause during 2014. Adjusted for age, sex, and race/ethnicity, the rate of diabetes-related ESRD was 154.4 per 1 million persons.

The National Diabetes Statistics Report is a periodic update on diabetes in the US, with estimates drawn from CDC data systems and other sources. The 2017 report estimates that 9.4% of all Americans—and 12% of adults—are affected by diagnosed or undiagnosed diabetes. In the absence of a physician diagnosis, diabetes was defined as a fasting plasma glucose level of 126 mg/dL or higher, or an HbA1c level of 6.5% or higher. Prediabetes was defined as fasting plasma glucose of 100 to 125 mg/dL or HbA1c of 5.7% to 6.4%.

The estimates don’t differentiate between type 1 and type 2 diabetes. “However,” the report states, “because type 2 diabetes accounts for 90% to 95% of all diabetes cases, the data presented are likely to be more characteristic of type 2 diabetes.” Overall prevalence appeared steady—the previous CDC diabetes statistical report, issued in 2014, estimated about 29 million Americans with diabetes, or 9.3% of the population.

In 2015, an estimated 1.5 million US adults received a new diagnosis of diabetes.

The prevalence data suggested that more women had diagnosed diabetes than men, but that differential may not mean much, as more men had undiagnosed diabetes (4.0 million men versus 3.1 million women). Also, most adults with diabetes were of working age: 4.6 million aged 18 to 44 and 14.3 million aged 45 to 64. At age 65 or older, total diabetes prevalence was 25.2%.

Analysis by race/ethnicity found that diabetes prevalence was highest for American Indians/Alaska Natives, 15.1%; followed by non-Hispanic blacks, 12.7%; Hispanics, 12.1%; Asians, 8.0%; and non-Hispanic whites, 7.4%. Within these categories, there were some important differences by subgroup: prevalence was 13.8% among Mexican Americans, 12.0% among Puerto Ricans, and 11.2% in Asian Indians.

Education, an indicator of socioeconomic status, was also related to diabetes prevalence: 12.6% for adults with less than a high school education, 9.5% for those with a high school education, and 7.2% for those with more than a high school education.

Estimates for prediabetes were staggering—33.9% of US adults in 2015, or 84.1 million people. That included nearly half (48.3%) of adults aged 65 or older. The figures were somewhat lower than in the 2014 report, which estimated that 86 million US adults had prediabetes.

Only 11.6% of adults with prediabetes were aware of their condition. In contrast to the situation with diabetes, there was no significant difference in the prevalence of prediabetes by racial/ethnic group.

High burden of complications and death

“Persons with diabetes are at higher risk of developing serious complications, including blindness, lower extremity amputation, and kidney failure,” said Nilka Ríos Burrows, MPH, of the CDC’s Chronic Kidney Disease Initiative, Division of Diabetes Translation. “However, people with diabetes can take steps (e.g., keeping blood sugar and blood pressure levels under control) to manage their diabetes and delay or prevent complications.”

Diabetes was a listed diagnosis in 7.2 million hospital discharges in US adults in 2014, including 1.5 million discharges for cardiovascular disease: a crude rate of 70.4 per 1000 persons with diabetes. These included approximately 400,000 patients with ischemic heart disease and more than 250,000 with stroke. There were 108,000 hospitalizations for lower extremity amputations and 168,000 for ketoacidosis.

Diabetes was listed as any diagnosis in 14.2 million emergency department visits, including 245,000 visits for hypoglycemia and 207,000 for hyperglycemic crisis. Diabetes was the seventh-leading cause of death in the US in 2015, with a crude rate of 24.7 per 100,000 persons.

Total direct and indirect costs of diagnosed diabetes in the US were estimated at $245 billion in 2012, according to research by the American Diabetes Association. With adjustment for age and sex, average medical costs for people with diabetes were 2.34 times higher than for those without diabetes.

For nephrologists, the high prevalence of diabetes and prediabetes heralds high rates of diabetic nephropathy in the years ahead. “More than 30 million people in the United States are living with diabetes, placing them at risk of developing kidney disease,” Ríos Burrows said.

A recent report by the CDC’s Chronic Kidney Disease Surveillance Team estimated that 36.5% of adults with diagnosed diabetes had stage 1 to 4 CKD during 2011–2012. As reported last year in ASN Kidney News, that study found continued increases among African Americans. The authors highlighted the need for continued vigilance to lessen the impact of CKD in the population, including efforts on the part of nephrologists to promote better awareness and care among primary care clinicians.

“Claims data indicate that testing for urine albumin, the earliest marker of kidney disease in diabetes, is done in less than half of patients,” Ríos Burrows said. “Testing for kidney disease among people who are at high risk for developing CKD—those with diabetes or with high blood pressure—has been shown to be a cost-effective tool to identify people with CKD. CDC’s kidney team is currently designing an online tool to help primary care physicians and other health care providers evaluate a patient’s need for and frequency of screening for CKD.” The latest CDC National CKD Fact Sheet can be found at https://www.cdc.gov/diabetes/pubs/pdf/kidney_factsheet.pdf.

What are diabetes rates in your area?

The 2017 National Diabetes Statistics report includes age-adjusted, county-level data on adult diabetes prevalence, providing a unique snapshot of diagnosed diabetes, based on 2013 data from the US Diabetes Surveillance System.

Median county-level prevalence was 9.4%. Age-adjusted prevalence of diagnosed diabetes varied widely: from 3.8% in Eagle County, Colorado, to 20.8% in Lowndes County, Alabama. The data can be explored in depth at https://www.cdc.gov/diabetes/atlas/countydata/atlas.html.