Measures of the burden of chronic kidney disease (CKD) have risen dramatically in the 21st century—including more than 50% increases in rates of premature death and disability-adjusted life-years due to CKD. Those are among the alarming findings of a new analysis of changes in the health impact of CKD, published in late 2018 in JAMA Network Open ( 1).
The rising burden of CKD has occurred at a time when the United States has seen declining health burdens overall and from noncommunicable diseases in particular, according to the analysis of national and state-level data.
“Clearly, there needs to be more emphasis on prevention and addressing risk factors, but also on therapies to treat or reverse CKD,” said senior author Ziyad Al-Aly, MD, of the Washington University School of Medicine in St. Louis and Veterans Affairs of St. Louis Health Care System. “Our report should be used to raise awareness of CKD among policymakers—unfortunately, it is often ignored—and CKD should be included in the public health agendas at the county, state, and federal levels. This report should be also used to advocate for more research funding in kidney disease, which in our view should be aligned with the burden of disease.”
The study raises special concerns about the rising impact of CKD in younger Americans. “We expected to see that burden of CKD would rise as the US population aged,” Al-Aly said. “But we were alarmed that the probability of death increased among those in the 20- to 54-year age group and that this increase was mostly driven by death due to diabetic CKD.
“Our findings suggest not only increased burden of CKD among this segment of the population, but that it was driven by increased exposure to metabolic and dietary risk factors and, most alarmingly, this has resulted in increased probability of death due to CKD among this young age group. Metabolic and dietary risks among this age group should be targeted aggressively to reduce burden of CKD.”
Measures of CKD burden increase nationwide
The researchers analyzed 2002–2016 data from the Global Burden of Disease study (2). The baseline year corresponded to the introduction of the National Kidney Foundation’s Kidney Disease Outcome Quality Initiative (K/DOQI) clinical practice guidelines; CKD was defined as an estimated glomerular filtration rate of under 60 mL/min/1.73 m2. Al-Aly’s coauthors were Benjamin Bowe, MPH, Yan Xie, MPH, Tingting Li, MD, Ali H. Mokdad, PhD, Hong Xian, PhD, Yan Yan, MD, PhD, and Geetha Maddukuri, MD.
The researchers analyzed estimates of CKD burden for all 50 states and Washington, DC. Trends in CKD mortality attributable to diabetes, hypertension, glomerulonephritis, and other causes were analyzed to obtain location-, sex-, age-, and year-specific estimates, along with estimates of nonfatal outcomes. The analyses used data and methods developed by the GBD collaborator network, including integrative metaregression methodology, an approach that integrates all available evidence to estimate the burden of CKD and other health conditions under the same computational framework.
“This allows us to compare the burden of kidney disease vis a vis the burden of other diseases,” Al-Aly said. “You can think of it as a summary estimate of all that we know about the epidemiology of CKD in the United States over the past 15 years.”
The study focused on four measures of CKD burden, all of which showed major changes from 2002 to 2016:
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Deaths due to CKD rose from 52,127 to 82,532, an increase of 58.3%. Nationwide, the rate of CKD deaths increased from 18 to 26 per 100,000 population, a 41.1% increase. Standardized for age, the rate of death from CKD rose from 14 to 16 per 100,000 population: a 17.9% increase.
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Disability-adjusted life years (DALYs) lost to CKD jumped from about 1.3 million to over 1.9 million: a 52.6% increase. Age-standardized DALY rates increased from 371 to 440 per 100,000 population, an increase of 18.6%.
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Years living with disability (YLD) due to CKD increased by 47.8% overall. The age-standardized YLD rate in 2016 was 170 per 100,000 population, for a 17.7% increase compared with 2002.
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Years of life lost (YLL) due to CKD exceeded 1.2 million years in 2016, representing a 55.6% increase. The age-standardized YLL rate was 270 per 100,000 population, a 19.3% increase.
Age-standardized death rates increased by 20.0% for CKD due to diabetes, 19.8% for hypertension, 11.1% for glomerulonephritis, and 11.0% for other causes. For age-standardized DALYs, rates were 21.8% for diabetes, 22.0% for hypertension, 10.4% for glomerulonephritis, and 10.3% for other causes. The age-standardized YLD rate for CKD due to diabetes was 61.8%.
Significant variation by state
While the increase in CKD burden was observed nationwide, there were substantial variations between states. The states with the highest age-standardized DALY rates were Mississippi, Louisiana, and Alabama: 697, 681, and 604 DALYs per 100,000 population, respectively. The states with the lowest rates were Vermont, Washington, and Colorado: 321, 328, and 331 DALYs per 100,000.
The magnitude of the increase in DALYs due to CKD was greatest in Oklahoma, 32.9%; West Virginia, 31.3%; and Texas, 30.9%. The states with the least increase in age-standardized DALYs were Nevada, 6.3%; New Jersey, 6.8%; and Massachusetts, 8.8%. The researchers note that the states with greater increases in CKD also have the highest adult obesity rates.
Deaths from CKD also varied widely among the states: the age-standardized death rate was more than twice as high in Louisiana compared to Vermont (28 versus 11 per 100,000 population). The largest changes in age-standardized CKD death rate were seen in Iowa, 41.0%; Washington, 38.1%; and Idaho, 34.6%. The smallest changes were in Nevada, −2.8%; New Jersey, 2.9%; and Massachusetts, 5.4%.
Decomposition analyses were performed to explore possible explanatory factors. Of the national increase in DALYs, 40.3% was due to increased risk exposure, 32.3% to aging, and 27.4% to population growth. Metabolic risk factors accounted for 93.8% of the overall change in age-standardized CKD DALY rates. The main contributors were:
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High fasting plasma glucose: a 29.5% change from 2002 to 2016 was linked to a 9.3% increase in age-standardized DALYs.
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High body mass index: a 30.9% change contributed to a 6.2% increase in DALYs.
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High systolic blood pressure: a 10.1% change resulted in a 2.3% increase in DALYs.
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Dietary risks—especially high intake of sodium and sugar-sweetened beverages—contributed to 5.3% of the change in age-standardized CKD DALY rates.
Diabetes and high blood pressure were the major factors associated with CKD-related disability. A 21.8% increase in CKD due to diabetes contributed to an 11.8% increase in age-standardized DALY rates nationwide, while a 22.0% increase in CKD due to hypertension led to a 4.0% increase in DALYs. Glomerulonephritis and other causes of CKD led to 1.1% and 1.7% increases in DALYs, respectively.
Special concern about CKD trends before age 55
The absolute probability of death due to CKD in younger adults (20 to 54 years) remained small, increasing 0.099% in 2002 to 0.125% in 2016. However, this represented a substantial increase of 26.8%. In this age group, 69.1% of the increased probability of death due to CKD was attributable to diabetes. Mississippi, Louisiana, and Alabama had the largest increases in probability of death due to CKD in younger adults.
In older adults aged 55 to 89, the probability of death due to CKD rose from 1.95% to 2.45%, for an increase of 25.6%. Diabetes accounted for 34.8% of the increase and a lower probability of death from competing causes for 37.2%.
As measured by the sociodemographic index (SDI), a standardized composite measurement used in the Global Burden of Disease study, sociodemographic development in the United States increased from 2002 to 2016. The increase in SDI was accompanied by a decrease in age-standardized DALY rates from all causes and from noncommunicable diseases.
But CKD was the exception. “Chronic kidney disease diverged from this trend in that as SDI increased, age-standardized DALY rate of CKD increased,” Al-Aly and colleagues write. With the change in sociodemographic development, age-standardized CKD DALY rates increased in all states; the sole exception was Washington, DC. The burden of CKD nationwide and at the state level increased despite significant decreases in communicable, maternal, neonatal, and nutritional diseases, as well as noncommunicable diseases.
Of special concern is the rising probability of death due to CKD in younger adults, with diabetes being by far the greatest contributor. The rising burden of CKD in this age group has serious consequences not just for health and well-being, but also for the economy.
“If CKD is developing earlier in life, it’s affecting the part of the population that contributes most to economic prosperity and human capital,” said Al-Aly. “And since these patients have more years to live, the costs to the healthcare system and the burden to themselves [are] going to be huge.”
The authors note that the increasing burden of CKD is “antithetical” to the declines in all-cause and noncommunicable disease burden, tied to increased sociodemographic development. “This finding may reflect the degree to which progress has been made in addressing the burden of cardiovascular disease (which shares several risk factors with CKD) and the relative stagnation in progress in addressing the burden of CKD,” Al-Aly and colleagues write. Sociodemographic progress may be associated with increased exposure to dietary risk factors and “more pronounced expression of metabolic risk factors,” such as obesity and diabetes.
From a clinical standpoint, the findings highlight the need for continued efforts to reduce lifestyle risks. “The focus should be on reducing risk exposure including metabolic and dietary risks among young adults,” Al-Aly noted. “We expect things to improve with time, but for CKD the story is remarkably different—we are doing worse now than we did 15 years ago, and this should not be acceptable.”
He called for concerted efforts regarding CKD risk factors at the state and national policy levels, with efforts to address factors contributing to the increase in CKD. “For example, we know that availability of calorie-dense foods and sugar-sweetened beverages [is] driving up obesity rates and diabetes,” he said. “Policy interventions should be devised to steer people away from these—policy tools could include taxes, and incentives for more healthful options. Equally important is to address the issue with the food and beverage industries.” He cited the US ban on trans fats as a successful example.
The findings also have implications for action by ASN and other specialty and professional groups, according to Al-Aly. “I think there needs to be a realization that this train is moving really fast and urgent attention is needed to deal with it today, and to prepare the nation to address the consequences of this epidemic in tomorrow’s world.”
References
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Bowe B , et al.. Changes in the US burden of chronic kidney disease from 2002 to 2016: An analysis of the Global Burden of Disease Study. JAMA Netw Open. 2018; 1(7):e184412. doi:10.1001/jamanetworkopen.2018.4412
