High Rates of Obesity, CKD Found in Type 1 Diabetes

Miriam E. Tucker

January 26, 2022

The rate of obesity is on the rise in people with type 1 diabetes and is associated with an increased risk for chronic kidney disease (CKD), new research finds.

The results were published online January 26 in The Journal of Clinical Endocrinology & Metabolism by Amelia S. Wallace, a PhD student at the Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, and colleagues.

The study, from Geisinger Health System in central Pennsylvania, included an unusually large cohort of over 4000 patients with type 1 diabetes and compared them with more than 130,000 people with type 2 diabetes. Those with type 1 diabetes had obesity rates similar to that of the general population, and after age adjustment, had a higher prevalence of CKD than those with type 2 diabetes.  

"Aging adults with type 1 diabetes are a growing population in the United States, and they suffer from a high chronic disease burden. Obesity, once thought to be rare in people with type 1 diabetes, has reached general population prevalence. Screening for kidney disease is not universal, yet the age-adjusted prevalence of CKD is higher in type 1 diabetes than even type 2 diabetes," Wallace and colleagues write.

In type 2 diabetes, obesity is thought to contribute to kidney disease indirectly through increased blood pressure and hyperglycemia and also directly through the increased metabolic demands of higher body weight and the endocrine effects of adipose tissue. This relationship hasn't been well-studied in type 1 diabetes, the authors note.  

Low eGFR More Common in Type 1 Diabetes, After Age Adjustment

The study population included 4060 patients with type 1 diabetes and 136,458 patients with type 2 diabetes in the Geisinger system from 2004-2018. Obesity was defined as a body mass index ≥ 30 kg/m2, a low estimated glomerular filtration rate (eGFR) (≤ 60 mL/min/1.73m2), and albuminuria (urine albumin-to-creatinine ratio [ACR] ≥ 30 mg/g). A comparison group of the general US population without diabetes came from the National Health and Nutrition Examination Survey, 1999-2018.

At study entry, the average age of those with type 1 diabetes was 39 years, significantly lower than the general population (43 years) and type 2 diabetes group (62 years).

Among those with type 1 diabetes, the prevalence of obesity increased from 32.6% in 2004 to 36.8% in 2018 (P trend = .0091). Both the crude and adjusted prevalence of obesity was similar between those with type 1 diabetes and the general population. It was much higher in the type 2 diabetes group, rising from 58.1% in 2004 to 61.6% in 2018.

The prevalence of low eGFR remained stable over the study period among those with type 1 diabetes, at 17.5% in 2004 and 16.1% in 2018. The 2004 rate of 17.5% was higher than general population (5.7%) and lower than the type 2 diabetes population (26.6%). However, after adjustment for age, sex, and race, the prevalence of low eGFR in all years was higher for those with type 1 diabetes than type 2 diabetes; in 2018, those values were 16.2% versus 9.3%, respectively.  

Results were similar for the prevalence of albuminuria, which was higher among those with type 2 diabetes in the crude analysis but higher among those with type 1 diabetes after adjustment.

Screening for Kidney Function Not Universal

Screening for eGFR was much more common than for ACR throughout the study period for both types of diabetes. In 2003-2004, 85% of those with type 1 diabetes had eGFR screening, which dropped to about 80% in 2009-2012 and rose to almost 90% in 2017-2018. For type 2 diabetes, eGFR screening was about 90% throughout.

However, screening rates for albuminuria were below 75% for both types of diabetes in all years but higher in type 1 diabetes than in type 2 diabetes.  

Obesity, Kidney Function Linked

In those with type 1 diabetes, obesity was associated with a significantly greater odds of low eGFR (odds ratio [OR], 1.52) after adjustment for age, sex, and race. The odds of albuminuria were also higher with obesity, although not significantly. In both cases, the relationship was attenuated after adjustment for hypertension.

In those with type 2 diabetes, obesity was associated with a significantly higher odds of low eGFR (OR, 1.29) and albuminuria (OR, 1.13), which remained significant after adjusting for hypertension. Obesity was also associated with a higher odds of low eGFR in the general population but to a lesser degree than in either diabetes group.

"The increase in obesity among type 1 diabetes is concerning for the future kidney health of these patients. Our results highlight the importance of routine screening for kidney disease, particularly in adults with type 1 diabetes and perhaps especially in those with obesity," Wallace and colleagues write.

The study was funded by the National Institutes of Health. Wallace and colleagues have no further disclosures.

J Clin Endocrinol Metab. Published online January 26, 2022. Abstract

Miriam E. Tucker is a freelance journalist based in the Washington, DC, area. She is a regular contributor to Medscape, with other work appearing in The Washington Post, NPR's Shots blog, and Diabetes Forecast magazine. She is on Twitter: @MiriamETucker.

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